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AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
Hanser, F., Pfeifer, B., Modre, R., Fischer, G., Seger, M., Hintermüller, C., Tilg, B., Hintringer, F. and Roithinger, F.X. Atrial and ventricular activation time imaging 2004
Vol. 1268CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004, pp. 1132-1137 
inproceedings  
BibTeX:
@inproceedings{Hanser2004,
  author = {Friedrich Hanser and Bernhard Pfeifer and Robert Modre and Gerald Fischer and Michael Seger and Christoph Hintermüller and Bernhard Tilg and Florian Hintringer and Franz Xaver Roithinger},
  title = {Atrial and ventricular activation time imaging},
  booktitle = {CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004},
  publisher = {Elsevier},
  year = {2004},
  volume = {1268},
  pages = {1132--1137}
}
Hintermuller, C., Fischer, G., Seger, M., Pfeifer, B., Hanser, F., Modre, R. and Tilg, B. Multi-lead ECG electrode array for clinical application of electrocardiographic inverse problem. 2004 Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
Vol. 2004, pp. 1941-1944 
article DOI  
Abstract: Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as easy and fast application. In this study we propose a new electrode array which improves the information content in the ECG map, considering clinical constraints such as easy to apply and compatibility with routine leads. A major challenge is the development of an electrode array which yields a high information content even for a large interindividual variation in torso shape. For identifying regions of high information content we introduce the concept of a locally applied virtual electrode array. As a result of our analysis we constructed a new electrode array consisting of two L-shaped regular spaced parts and compared it to the electrode array we use for clinical studies upon activation time imaging. We assume that one side effect caused by the regular shape and spacing of the new array be that the reconstruction of electrodes placed on the patients back is simplified. It may be sufficient to record a few characteristic electrode positions and merge them with a model of the posterior array.
BibTeX:
@article{Hintermuller2004,
  author = {Hintermuller, Christoph and Fischer, Gerald and Seger, Michael and Pfeifer, Bernhard and Hanser, Friedrich and Modre, Robert and Tilg, Bernhard},
  title = {Multi-lead ECG electrode array for clinical application of electrocardiographic inverse problem.},
  journal = {Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference},
  year = {2004},
  volume = {2004},
  pages = {1941--1944},
  doi = {https://doi.org/10.1109/IEMBS.2004.1403574}
}
Pfeifer, B., Hanser, F., Hintermüller, C., Modre-Osprian, R., Fischer, G., Seger, M. and Tilg, B. Model-based atrial and ventricular myocardium extraction 2004
Vol. 1268CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004, pp. 1370 
inproceedings  
BibTeX:
@inproceedings{Pfeifer2004,
  author = {Bernhard Pfeifer and Friedrich Hanser and Christoph Hintermüller and Robert Modre-Osprian and Gerald Fischer and Michael Seger and Bernhard Tilg},
  title = {Model-based atrial and ventricular myocardium extraction},
  booktitle = {CARS 2004. Computer Assisted Radiology and Surgery. Proceedings of the 18th International Congress and Exhibition, Chicago, USA, June 23-26, 2004},
  publisher = {Elsevier},
  year = {2004},
  volume = {1268},
  pages = {1370}
}
Pfeifer, B., Hanser, F., Hintermüller, C., Modre-Osprian, R., Fischer, G., Seger, M., Kremser, C. and Tilg, B. Atrial myocardium model extraction 2004
Vol. 5367Medical Imaging 2004: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 14-19 February 2004 
inproceedings DOI  
BibTeX:
@inproceedings{Pfeifer2004a,
  author = {Bernhard Pfeifer and Friedrich Hanser and Christoph Hintermüller and Robert Modre-Osprian and Gerald Fischer and Michael Seger and Christian Kremser and Bernhard Tilg},
  title = {Atrial myocardium model extraction},
  booktitle = {Medical Imaging 2004: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 14-19 February 2004},
  publisher = {SPIE},
  year = {2004},
  volume = {5367},
  doi = {https://doi.org/10.1117/12.533960}
}
Seger, M., Fischer, G., Modre, R., Hanser, F., Pfeifer, B., Hintermuller, C., Roithinger, F.X., Hintringer, F., Trieb, T., Schocke, M. and Tilg, B. Simulation of atrial electrophysiology and body surface potentials for normal and abnormal rhythm. 2004 Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
Vol. 2004, pp. 817-820 
article DOI  
Abstract: The effect of different atrial electrical activation sequences (sinus rhythm and atrial flutter circling in the right atrium) on the body surface potentials is investigated in this study. A realistic volume conductor model consisting of atria, lungs, chest and blood masses is generated from image stacks recorded by magnetic resonance imaging. The electrical sources-the transmembrane potentials-within the atrial volumetric model are simulated for different atrial rhythms employing a cellular automaton capable of considering different parameters depending on the specific properties of the tissues. The potentials on the torso surface are computed applying the finite element method for solving the differential equations derived from the bidomain theory. Both the simulated atrial activation patterns and the computed torso potentials for atrial sinus rhythm and atrial flutter are in qualitatively and quantitatively good agreement with data measured in humans. The simulation of body surface potentials generated by different electrical activation sequences in the atria or ventricles allows testing and assessing noninvasive imaging of cardiac electrophysiology, as both the potentials on the body surface and the reference activation in the heart are available.
BibTeX:
@article{Seger2004,
  author = {Seger, Michael and Fischer, Gerald and Modre, Robert and Hanser, Friedrich and Pfeifer, Bernhard and Hintermuller, Christoph and Roithinger, Franz Xaver and Hintringer, Florian and Trieb, Thomas and Schocke, Michael and Tilg, Bernhard},
  title = {Simulation of atrial electrophysiology and body surface potentials for normal and abnormal rhythm.},
  journal = {Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference},
  year = {2004},
  volume = {2004},
  pages = {817--820},
  doi = {https://doi.org/10.1109/IEMBS.2004.1403283}
}
Seger, M., Fischer, G., Modre, R., Pfeifer, B., Hanser, F., Hintermüller, C., Hintringer, F., Roithinger, F.X., Trieb, T., Schocke, M. and Tilg, B. Online Noninvasive Localization of Accessory Pathways in the EP Lab 2004
Vol. 3217Medical Image Computing and Computer-Assisted Intervention -- MICCAI 2004, 7th International Conference Saint-Malo, France, September 26-29, 2004, Proceedings, Part II, pp. 502-509 
inproceedings DOI URL 
BibTeX:
@inproceedings{Seger2004a,
  author = {Michael Seger and Gerald Fischer and Robert Modre and Bernhard Pfeifer and Friedrich Hanser and Christoph Hintermüller and Florian Hintringer and Franz Xaver Roithinger and Thomas Trieb and Michael Schocke and Bernhard Tilg},
  title = {Online Noninvasive Localization of Accessory Pathways in the EP Lab},
  booktitle = {Medical Image Computing and Computer-Assisted Intervention -- MICCAI 2004, 7th International Conference Saint-Malo, France, September 26-29, 2004, Proceedings, Part II},
  publisher = {Springer},
  year = {2004},
  volume = {3217},
  pages = {502--509},
  url = {https://doi.org/10.1007/978-3-540-30136-3_62},
  doi = {https://doi.org/10.1007/978-3-540-30136-3%5C_62}
}
Fischer, G., Pfeifer, B., Seger, M., Hintermüller, C., Hanser, F., Modre, R., Tilg, B., Trieb, T., Kremser, C., Roithinger, F.X. and Hintringer, F. Computationally efficient noninvasive cardiac activation time imaging. 2005 Methods of information in medicine
Vol. 44, pp. 674-686 
article  
Abstract: The computer model-based computation of the cardiac activation sequence in humans has been recently subject of successful clinical validation. This method is of potential interest for guiding ablation therapy of arrhythmogenic substrates. However, computation times of almost an hour are unattractive in a clinical setting. Thus, the objective is the development of a method which performs the computation in a few minutes run time. The computationally most expensive part is the product of the lead field matrix with a matrix containing the source pattern on the cardiac surface. The particular biophysical properties of both matrices are used for speeding up this operation by more than an order of magnitude. A conjugate gradient optimizer was developed using C++ for computing the activation map. The software was tested on synthetic and clinical data. The increase in speed with respect to the previously used Fortran 77 implementation was a factor of 30 at a comparable quality of the results. As an additional finding the coupled regularization strategy, originally introduced for saving computation time, also reduced the sensitivity of the method to the choice of the regularization parameter. As it was shown for data from a WPWpatient the developed software can deliver diagnostically valuable information at a much shorter span of time than current clinical routine methods. Its main application could be the localization of focal arrhythmogenic substrates.
BibTeX:
@article{Fischer2005,
  author = {Fischer, G. and Pfeifer, B. and Seger, M. and Hintermüller, C. and Hanser, F. and Modre, R. and Tilg, B. and Trieb, T. and Kremser, C. and Roithinger, F. X. and Hintringer, F.},
  title = {Computationally efficient noninvasive cardiac activation time imaging.},
  journal = {Methods of information in medicine},
  year = {2005},
  volume = {44},
  pages = {674--686}
}
Fischer, G., Hanser, F., Pfeifer, B., Seger, M., Hintermüller, C., Modre, R., Tilg, B., Trieb, T., Berger, T., Roithinger, F.X. and Hintringer, F. A signal processing pipeline for noninvasive imaging of ventricular preexcitation. 2005 Methods of information in medicine
Vol. 44, pp. 508-515 
article  
Abstract: Noninvasive imaging of the cardiac activation sequence in humans could guide interventional curative treatment of cardiac arrhythmias by catheter ablation. Highly automated signal processing tools are desirable for clinical acceptance. The developed signal processing pipeline reduces user interactions to a minimum, which eases the operation by the staff in the catheter laboratory and increases the reproducibility of the results. A previously described R-peak detector was modified for automatic detection of all possible targets (beats) using the information of all leads in the ECG map. A direct method was applied for signal classification. The algorithm was tuned for distinguishing beats with an adenosine induced AV-nodal block from baseline morphology in Wolff-Parkinson-White (WPW) patients. Furthermore, an automatic identification of the QRS-interval borders was implemented. The software was tested with data from eight patients having overt ventricular preexcitation. The R-peak detector captured all QRS-complexes with no false positive detection. The automatic classification was verified by demonstrating adenosine-induced prolongation of ventricular activation with statistical significance (p <0.001) in all patients. This also demonstrates the performance of the automatic detection of QRS-interval borders. Furthermore, all ectopic or paced beats were automatically separated from sinus rhythm. Computed activation maps are shown for one patient localizing the accessory pathway with an accuracy of 1 cm. The implemented signal processing pipeline is a powerful tool for selecting target beats for noninvasive activation imaging in WPW patients. It robustly identifies and classifies beats. The small beat to beat variations in the automatic QRS-interval detection indicate accurate identification of the time window of interest.
BibTeX:
@article{Fischer2005a,
  author = {Fischer, G. and Hanser, F. and Pfeifer, B. and Seger, M. and Hintermüller, C. and Modre, R. and Tilg, B. and Trieb, T. and Berger, T. and Roithinger, F. X. and Hintringer, F.},
  title = {A signal processing pipeline for noninvasive imaging of ventricular preexcitation.},
  journal = {Methods of information in medicine},
  year = {2005},
  volume = {44},
  pages = {508--515}
}
Fischer, G., Hanser, F., Pfeifer, B., Seger, M., Hintermüller, C., Modre, R., Tilg, B., Trieb, T., Berger, T., Roithinger, F.X. and Hintringer, F. A signal processing pipeline for noninvasive imaging of ventricular preexcitation 2005 Methods of Information in Medicine
Vol. 44(4), pp. 508-515 
inproceedings DOI  
Abstract: Objectives: Noninvasive imaging of the cardiac activation sequence in humans could guide interventional curative treatment of cardiac arrhythmias by catheter ablation. Highly automated signal processing tools are desirable for clinical acceptance. The developed signal processing pipeline reduces user interactions to a minimum, which eases the operation by the staff in the catheter laboratory and increases the reproducibility of the results. Methods: A previously described R-peak detector was modified for automatic detection of all possible targets (beats) using the information of all leads in the ECG map. A direct method was applied for signal classification. The algorithm was tuned for distinguishing beats with an adenosine induced AV-nodal block from baseline morphology in Wolff-Parkinson-White (WPW) patients. Furthermore, an automatic identification of the QRS-interval borders was implemented. Results: The software was tested with data from eight patients having overt ventricular preexcitation. The R-peak detector captured all QRS-complexes with no false positive detection. The automatic classification was verified by demonstrating adenosine-induced prolongation of ventricular activation with statistical significance (p <0.001) in all patients. This also demonstrates the performance of the automatic detection of QRS-interval borders. Furthermore, all ectopic or paced beats were automatically separated from sinus rhythm. Computed activation maps are shown for one patient localizing the accessory pathway with an accuracy of 1 cm. Conclusions: The implemented signal processing pipeline is a powerful tool for selecting target beats for noninvasive activation imaging in WPW patients. It robustly identifies and classifies beats. The small beat to beat variations in the automatic QRS-interval detection indicate accurate identification of the time window of interest. © 2005 Schattauer GmbH.
BibTeX:
@inproceedings{Fischer2005b,
  author = {Fischer, Gerald and Hanser, F. and Pfeifer, B. and Seger, M. and Hintermüller, C. and Modre, R. and Tilg, B. and Trieb, T. and Berger, T. and Roithinger, F. X. and Hintringer, F.},
  title = {A signal processing pipeline for noninvasive imaging of ventricular preexcitation},
  journal = {Methods of Information in Medicine},
  publisher = {Schattauer GmbH},
  year = {2005},
  volume = {44},
  number = {4},
  pages = {508--515},
  doi = {https://doi.org/10.1055/s-0038-1634001}
}
Hintermuller, C., Fischer, G., Seger, M., Pfeifer, B., Modre, R. and Tilg, B. Rank Based Selection of Electrode Positions for a Multi-Lead ECG Electrode Array. 2005 Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
Vol. 2005, pp. 2379-2382 
article DOI  
Abstract: Methods for noninvasive imaging of electrical function of the heart seem to become a clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as easy and fast application. In this study we propose a new electrode array meeting clinical requirements such as easy to apply and compatibility with routine leads. Within body surface regions of high sensitivity, identified in a prior, information content based study, the number of required electrodes was optimized using effort-gain plots. These plots were generated by applying a so called type one detector criterion. The optimal array was selected from a set of 12 electrode arrays. Each of them consists of two L-shaped regular spaced parts. The optimal array was found by comparing several layouts and electrode densities to the electrode array we use for clinical studies. It consists of 125 electrodes with a regular spacing between 2cm and 3cm.
BibTeX:
@article{Hintermuller2005,
  author = {Hintermuller, Christoph and Fischer, Gerald and Seger, Michael and Pfeifer, Bernhard and Modre, Robert and Tilg, Bernhard},
  title = {Rank Based Selection of Electrode Positions for a Multi-Lead ECG Electrode Array.},
  journal = {Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference},
  year = {2005},
  volume = {2005},
  pages = {2379--2382},
  doi = {https://doi.org/10.1109/IEMBS.2005.1616945}
}
Pfeifer, B., Hanser, F., Trieb, T., Hintermüller, C., Seger, M., Fischer, G., Modre, R. and Tilg, B. Combining Active Appearance Models and Morphological Operators Using a Pipeline for Automatic Myocardium Extraction 2005
Vol. 3504Functional Imaging and Modeling of the Heart, Third International Workshop, FIMH 2005, Barcelona, Spain, June 2-4, 2005, Proceedings, pp. 44-53 
inproceedings DOI URL 
BibTeX:
@inproceedings{Pfeifer2005,
  author = {Bernhard Pfeifer and Friedrich Hanser and Thomas Trieb and Christoph Hintermüller and Michael Seger and Gerald Fischer and Robert Modre and Bernhard Tilg},
  title = {Combining Active Appearance Models and Morphological Operators Using a Pipeline for Automatic Myocardium Extraction},
  booktitle = {Functional Imaging and Modeling of the Heart, Third International Workshop, FIMH 2005, Barcelona, Spain, June 2-4, 2005, Proceedings},
  publisher = {Springer},
  year = {2005},
  volume = {3504},
  pages = {44--53},
  url = {https://doi.org/10.1007/11494621_5},
  doi = {https://doi.org/10.1007/11494621%5C_5}
}
Pfeifer, B., Hanser, F., Seger, M., Hintermüller, C., Modre-Osprian, R., Fischer, G., Mühlthaler, H., Trieb, T. and Tilg, B. Cardiac modeling using active appearance models and morphological operators 2005
Vol. 5744Medical Imaging 2005: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 12-17 February 2005 
inproceedings DOI  
BibTeX:
@inproceedings{Pfeifer2005a,
  author = {Bernhard Pfeifer and Friedrich Hanser and Michael Seger and Christoph Hintermüller and Robert Modre-Osprian and Gerald Fischer and Hannes Mühlthaler and Thomas Trieb and Bernhard Tilg},
  title = {Cardiac modeling using active appearance models and morphological operators},
  booktitle = {Medical Imaging 2005: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 12-17 February 2005},
  publisher = {SPIE},
  year = {2005},
  volume = {5744},
  doi = {https://doi.org/10.1117/12.591903}
}
Pfeifer, B., Hanser, F., Seger, M., Hintermüller, C., Modre-Osprian, R., Fischer, G., Mühlthaler, H., Trieb, T. and Tilg, B. A C++ framework for creating tissue specific segmentation-pipelines 2005
Vol. 5744Medical Imaging 2005: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 12-17 February 2005 
inproceedings DOI  
BibTeX:
@inproceedings{Pfeifer2005b,
  author = {Bernhard Pfeifer and Friedrich Hanser and Michael Seger and Christoph Hintermüller and Robert Modre-Osprian and Gerald Fischer and Hannes Mühlthaler and Thomas Trieb and Bernhard Tilg},
  title = {A C++ framework for creating tissue specific segmentation-pipelines},
  booktitle = {Medical Imaging 2005: Visualization, Image-Guided Procedures, and Display, San Diego, California, United States, 12-17 February 2005},
  publisher = {SPIE},
  year = {2005},
  volume = {5744},
  doi = {https://doi.org/10.1117/12.591915}
}
Berger, T., Fischer, G., Pfeifer, B., Modre, R., Hanser, F., Trieb, T., Roithinger, F.X., Stuehlinger, M., Pachinger, O., Tilg, B. and Hintringer, F. Single-Beat Noninvasive Imaging of Cardiac Electrophysiology of Ventricular Pre-Excitation 2006 Journal of the American College of Cardiology
Vol. 48(10), pp. 2045-2052 
article DOI  
Abstract: Objectives: The aim of this study was to determine whether noninvasive imaging of cardiac electrophysiology (NICE) is feasible in patients with Wolff-Parkinson-White (WPW) syndrome in the clinical setting of a catheter laboratory and to test the accuracy of the noninvasively obtained ventricular activation sequences as compared with that of standard invasive electroanatomic mapping. Background: NICE of ventricular activation could serve as a useful tool in the treatment of cardiac arrhythmias and might help improve our understanding of arrhythmia mechanisms. Methods: NICE works by fusing the data from high-resolution electrocardiographic mapping and a model of the patient's cardiac anatomy obtained by magnetic resonance imaging. The ventricular activation sequence was computed with a bidomain theory-based heart model to solve this inverse problem. Noninvasive imaging of cardiac electrophysiology was performed in 7 patients with WPW syndrome undergoing catheter ablation of the accessory pathway. The position error of NICE was defined as the distance between the site of earliest activation computed by NICE and the successful ablation site identified by electroanatomic mapping (CARTO; Biosense Webster, Diamond Bar, California) for normal atrioventricular (AV) conduction as well as for adenosine-induced AV block. Results: The error introduced by geometric coupling of the CARTO data and the NICE model was 5 ± 3 mm (model discretization 10 mm). All ventricular accessory pathway insertion sites were identified with an accuracy of 18.7 ± 5.8 mm (baseline) and 18.7 ± 6.4 mm (adenosine). Conclusions: The individual cardiac anatomy model obtained for each patient enables accurate noninvasive electrocardiographic imaging of ventricular pre-excitation in patients with WPW syndrome. Noninvasive imaging of cardiac electrophysiology might be used as a complementary noninvasive approach to localize the origin and help identify and understand the underlying mechanisms of cardiac arrhythmias. © 2006 American College of Cardiology Foundation.
BibTeX:
@article{Berger2006,
  author = {Berger, Thomas and Fischer, Gerald and Pfeifer, Bernhard and Modre, Robert and Hanser, Friedrich and Trieb, Thomas and Roithinger, Franz X. and Stuehlinger, Markus and Pachinger, Otmar and Tilg, Bernhard and Hintringer, Florian},
  title = {Single-Beat Noninvasive Imaging of Cardiac Electrophysiology of Ventricular Pre-Excitation},
  journal = {Journal of the American College of Cardiology},
  year = {2006},
  volume = {48},
  number = {10},
  pages = {2045--2052},
  doi = {https://doi.org/10.1016/j.jacc.2006.08.019}
}
Hintermüller, C., Seger, M., Pfeifer, B., Fischer, G. and Tilg, B. Simulation of Cardiac Activation Patterns for Checking Suggestions About the Suitability of Multi-lead ECG Electrode Arrays 2006
Vol. 4072Biomedical Simulation, Third International Symposium, ISBMS 2006, Zurich, Switzerland, July 10-11, 2006, Proceedings, pp. 105-112 
inproceedings DOI URL 
BibTeX:
@inproceedings{Hintermueller2006,
  author = {Christoph Hintermüller and Michael Seger and Bernhard Pfeifer and Gerald Fischer and Bernhard Tilg},
  title = {Simulation of Cardiac Activation Patterns for Checking Suggestions About the Suitability of Multi-lead ECG Electrode Arrays},
  booktitle = {Biomedical Simulation, Third International Symposium, ISBMS 2006, Zurich, Switzerland, July 10-11, 2006, Proceedings},
  publisher = {Springer},
  year = {2006},
  volume = {4072},
  pages = {105--112},
  url = {https://doi.org/10.1007/11790273_12},
  doi = {https://doi.org/10.1007/11790273%5C_12}
}
Hintermüller, C., Seger, M., Pfeifer, B., Fischer, G. and Tilg, B. A Model Based Approach for Multi-lead ECG Array Layout Selection 2006
Vol. 4190Medical Image Computing and Computer-Assisted Intervention - MICCAI 2006, 9th International Conference, Copenhagen, Denmark, October 1-6, 2006, Proceedings, Part I, pp. 264-271 
inproceedings DOI URL 
BibTeX:
@inproceedings{Hintermueller2006a,
  author = {Christoph Hintermüller and Michael Seger and Bernhard Pfeifer and Gerald Fischer and Bernhard Tilg},
  title = {A Model Based Approach for Multi-lead ECG Array Layout Selection},
  booktitle = {Medical Image Computing and Computer-Assisted Intervention - MICCAI 2006, 9th International Conference, Copenhagen, Denmark, October 1-6, 2006, Proceedings, Part I},
  publisher = {Springer},
  year = {2006},
  volume = {4190},
  pages = {264--271},
  url = {https://doi.org/10.1007/11866565_33},
  doi = {https://doi.org/10.1007/11866565%5C_33}
}
Hintermüller, C., Seger, M., Pfeifer, B., Fischer, G., Modre, R. and Tilg, B. Sensitivity- and effort-gain analysis: Multilead ECG electrode array selection for activation time imaging 2006 IEEE Transactions on Biomedical Engineering
Vol. 53(10), pp. 2055-2066 
article DOI  
Abstract: Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of ∼30 cm x 30 cm and ∼20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm. © 2006 IEEE.
BibTeX:
@article{Hintermueller2006b,
  author = {Hintermüller, Christoph and Seger, Michael and Pfeifer, Bernhard and Fischer, Gerald and Modre, Robert and Tilg, Bernhard},
  title = {Sensitivity- and effort-gain analysis: Multilead ECG electrode array selection for activation time imaging},
  journal = {IEEE Transactions on Biomedical Engineering},
  year = {2006},
  volume = {53},
  number = {10},
  pages = {2055--2066},
  doi = {https://doi.org/10.1109/TBME.2006.881797}
}
Hintermüller, C., Seger, M., Pfeifer, B., Fischer, G. and Tilg, B. A model based approach for multi-lead ECG array layout selection 2006 Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Vol. 4190 LNCS, pp. 264-271 
inproceedings DOI  
Abstract: In this study an approach for testing electrode array schemes with respect to their ability to improve the resolution of methods for activation time imaging is proposed. First local linear dependency maps are computed using a virtual array method. These maps depict the torso surface areas where the body surface potential is most sensitive to changes in the transmembrane potential. The optimal number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. From the sensitivity maps it was found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. The EG analysis revealed that the optimal array meeting clinical requirements and improving the resolution of activation time imaging consists of 125 electrodes. © Springer-Verlag Berlin Heidelberg 2006.
BibTeX:
@inproceedings{Hintermueller2006c,
  author = {Hintermüller, Christoph and Seger, Michael and Pfeifer, Bernhard and Fischer, Gerald and Tilg, Bernhard},
  title = {A model based approach for multi-lead ECG array layout selection},
  journal = {Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)},
  publisher = {Springer Verlag},
  year = {2006},
  volume = {4190 LNCS},
  pages = {264--271},
  doi = {https://doi.org/10.1007/11866565_33}
}
Hintermüller, C., Seger, M., Pfeifer, B., Fischer, G. and Tilg, B. Simulation of Cardiac Activation Patterns for Checking Suggestions About the Suitability of Multi-lead ECG Electrode Arrays 2006 , pp. 105-112  misc DOI  
BibTeX:
@misc{Hintermueller2006d,
  author = {Christoph Hintermüller and Michael Seger and Bernhard Pfeifer and Gerald Fischer and Bernhard Tilg},
  title = {Simulation of Cardiac Activation Patterns for Checking Suggestions About the Suitability of Multi-lead ECG Electrode Arrays},
  year = {2006},
  pages = {105-112},
  doi = {https://doi.org/10.1007/11790273_12}
}
Modre, R., Seger, M., Fischer, G., Hintermüller, C., Hayn, D., Pfeifer, B., Hanser, F., Schreier, G. and Tilg, B. Cardiac anisotropy: is it negligible regarding noninvasive activation time imaging? 2006 IEEE transactions on bio-medical engineering
Vol. 53, pp. 569-580 
article DOI  
Abstract: The aim of this study was to quantify the effect of cardiac anisotropy in the activation-based inverse problem of electrocardiography. Differences of the patterns of simulated body surface potential maps for isotropic and anisotropic conditions were investigated with regard to activation time (AT) imaging of ventricular depolarization. AT maps were estimated by solving the nonlinear inverse ill-posed problem employing spatio-temporal regularization. Four different reference AT maps (sinus rhythm, right-ventricular and septal pacing, accessory pathway) were calculated with a bidomain theory based anisotropic finite-element heart model in combination with a cellular automaton. In this heart model a realistic fiber architecture and conduction system was implemented. Although the anisotropy has some effects on forward solutions, effects on inverse solutions are small indicating that cardiac anisotropy might be negligible for some clinical applications (e.g., imaging of focal events) of our AT imaging approach. The main characteristic events of the AT maps were estimated despite neglected electrical anisotropy in the inverse formulation. The worst correlation coefficient of the estimated AT maps was 0.810 in case of sinus rhythm. However, all characteristic events of the activation pattern were found. The results of this study confirm our clinical validation studies of noninvasive AT imaging in which cardiac anisotropy was neglected.
BibTeX:
@article{Modre2006,
  author = {Modre, Robert and Seger, Michael and Fischer, Gerald and Hintermüller, Christoph and Hayn, Dieter and Pfeifer, Bernhard and Hanser, Friedrich and Schreier, Günter and Tilg, Bernhard},
  title = {Cardiac anisotropy: is it negligible regarding noninvasive activation time imaging?},
  journal = {IEEE transactions on bio-medical engineering},
  year = {2006},
  volume = {53},
  pages = {569--580},
  doi = {https://doi.org/10.1109/TBME.2006.870253}
}
Pfeifer, B., Seger, M., Hintermüller, C., Fischer, G., Hanser, F., Modre, R., Mühlthaler, H. and Tilg, B. Semiautomatic volume conductor modeling pipeline for imaging the cardiac electrophysiology noninvasively. 2006 Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention
Vol. 9, pp. 588-595 
article DOI  
Abstract: In this paper we present an approach for extracting patient individual volume conductor models (VCM) using volume data acquired from Magnetic Resonance Imaging (MRI) for computational biology of electrical excitation in the patient's heart. The VCM consists of the compartments chest surface, lung surfaces, the atrial and ventricular myocardium, and the blood masses. For each compartment a segmentation approach with no or little necessity of user interaction was implemented and integrated into a VCM segmentation pipeline to enable the inverse problem of electrocardiography to become clinical applicable. The segmentation pipeline was tested using volume data from ten patients with structurally normal hearts.
BibTeX:
@article{Pfeifer2006,
  author = {Pfeifer, Bernhard and Seger, Michael and Hintermüller, Christoph and Fischer, Gerald and Hanser, Friedrich and Modre, Robert and Mühlthaler, Hannes and Tilg, Bernhard},
  title = {Semiautomatic volume conductor modeling pipeline for imaging the cardiac electrophysiology noninvasively.},
  journal = {Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention},
  year = {2006},
  volume = {9},
  pages = {588--595},
  doi = {https://doi.org/10.1007/11866565_72}
}
Pfeifer, B., Seger, M., Hintermüller, C., Fischer, G., Hanser, F., Modre, R., Mühlthaler, H. and Tilg, B. Semiautomatic Volume Conductor Modeling Pipeline for Imaging the Cardiac Electrophysiology Noninvasively 2006
Vol. 4190Medical Image Computing and Computer-Assisted Intervention - MICCAI 2006, 9th International Conference, Copenhagen, Denmark, October 1-6, 2006, Proceedings, Part I, pp. 588-595 
inproceedings DOI URL 
BibTeX:
@inproceedings{Pfeifer2006a,
  author = {Bernhard Pfeifer and Michael Seger and Christoph Hintermüller and Gerald Fischer and Friedrich Hanser and Robert Modre and Hannes Mühlthaler and Bernhard Tilg},
  title = {Semiautomatic Volume Conductor Modeling Pipeline for Imaging the Cardiac Electrophysiology Noninvasively},
  booktitle = {Medical Image Computing and Computer-Assisted Intervention - MICCAI 2006, 9th International Conference, Copenhagen, Denmark, October 1-6, 2006, Proceedings, Part I},
  publisher = {Springer},
  year = {2006},
  volume = {4190},
  pages = {588--595},
  url = {https://doi.org/10.1007/11866565_72},
  doi = {https://doi.org/10.1007/11866565%5C_72}
}
Pfeifer, B., Fischer, G., Hanser, F., Seger, M., Hintermüller, C., Modre-Osprian, R., Trieb, T. and Tilg, B. Atrial and ventricular myocardium extraction using model-based techniques 2006 Methods of Information in Medicine
Vol. 45(1), pp. 19-26 
article DOI  
Abstract: Objectives: This paper presents an efficient approach for extracting myocardial structures from given atrial and ventricular blood masses to enable non-invasive estimation of electrical excitation in human atria and ventricles. Methods: Based on given segmented atrial and ventricular blood masses, the approach constructs the myocardial structure directly, in the case that the myocardium can be detected in the volume data, or by using mean model information, in the case that the myocardium cannot be seen in the volume data due to image modalities or artefacts. The approach employs mathematical and gray-value morphology operations. Regulated by the spatial visibility of the myocardial structure in the medical image data especially the atrial myocardium needs to be estimated repeatedly using the a-priori knowledge given by the anatomy. Results: The approach was tested using eight patient data sets. The reconstruction process yielded satisfying results with respect to an efficient generation of a volume conductor model which is essential when trying to implement the estimation of electrical excitation in clinical application. Conclusion: The approach yields ventricular and atrial models that qualify for cardiac source imaging in a clinical setting. © 2006 Schattauer GmbH.
BibTeX:
@article{Pfeifer2006b,
  author = {Pfeifer, Bernhard and Fischer, G. and Hanser, F. and Seger, M. and Hintermüller, C. and Modre-Osprian, R. and Trieb, T. and Tilg, B.},
  title = {Atrial and ventricular myocardium extraction using model-based techniques},
  journal = {Methods of Information in Medicine},
  publisher = {Schattauer GmbH},
  year = {2006},
  volume = {45},
  number = {1},
  pages = {19--26},
  doi = {https://doi.org/10.1055/s-0038-1634032}
}
Pfeifer, B., Seger, M., Hintermüller, C., Fischer, G., Mühlthaler, H., Modre-Osprian, R. and Tilg, B. AAM-based segmentation for imaging cardiac electrophysiology. 2007 Methods of information in medicine
Vol. 46, pp. 36-42 
article  
Abstract: Activation time (AT) imaging from electrocardiographic (ECG) mapping data has been developing for several years. By coupling 4-dimensional volume data (3D + time) the electrical sequence can be computed non-invasively. In this paper an approach for extracting the ventricular and atrial blood masses for structurally normal hearts by using cine-gated short-axis data obtained via magnetic resonance imaging (MRI) is introduced. The blood masses are extracted by employing Active Appearance Models (AAMs). The ventricular blood masses are segmented, applying the AAMs after providing apex cordis and base of the heart in the volume data, whereas the more complex geometry of the atria requires a more specific attempt. On account of this the atrium was divided into three divisions of appearance, where the images of the volume data in the related divisions have a maximum affinity. The first division reaches from the base of the heart to initial visibility of the upper and left lower pulmonary vein. The second division up from there to the last occurrence and the third division from there to the end of the visibility of the right upper and lower pulmonary vein. After extracting the cardiac blood masses the result gets triangulated and remeshed for activation time imaging. With this method the cardiac models of eight patients were extracted and the AT imaging approach was applied to single-beat ECG data of atrial and ventricular depolarization. The advantage of the proposed AAM approach is that only a few initial parameters have to be set. Therefore, the approach can be integrated into a processing pipeline that works semi-automatically. The extracted models can be used for further investigations.
BibTeX:
@article{Pfeifer2007,
  author = {Pfeifer, B. and Seger, M. and Hintermüller, C. and Fischer, G. and Mühlthaler, H. and Modre-Osprian, R. and Tilg, B.},
  title = {AAM-based segmentation for imaging cardiac electrophysiology.},
  journal = {Methods of information in medicine},
  year = {2007},
  volume = {46},
  pages = {36--42}
}
Pfeifer, B., Seger, M., Fischer, G., Nowak, C.-N., Aschaber, J. and Tilg, B. A Fast Volume Conductor Segmentation and Modeling Pipeline for NICE 2007 2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, pp. 136-139  inproceedings DOI  
Abstract: In this paper an approach for extracting patient individual volume conductor models (VCM) using volume data acquired from Magnetic Resonance Imaging (MRI) for computational biology of electrical excitation in the patient's individual heart is introduced. The VCM consists of the compartments chest, lung, atrial and ventricular myocardium and the blood masses. For each compartment a segmentation approach with no or little user interaction was developed and integrated into the VCM modeling pipeline to enable the inverse problem of electrocardiography to become clinical applicable.
BibTeX:
@inproceedings{Pfeifer2007a,
  author = {Bernhard Pfeifer and Michael Seger and Gerald Fischer and Claudia-Nike Nowak and Johannes Aschaber and Bernhard Tilg},
  title = {A Fast Volume Conductor Segmentation and Modeling Pipeline for NICE},
  journal = {2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging},
  publisher = {IEEE},
  year = {2007},
  pages = {136--139},
  doi = {https://doi.org/10.1109/NFSI-ICFBI.2007.4387708}
}
Pfeifer, B., Seger, M., Modre-Osprian, R., Hintermuller, C., Hayn, D., Schreier, G. and Tilg, B. Contributions of Epi-, Endo- and Myocardium to the Body Surface Potential 2007 2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, pp. 304-307  inproceedings DOI  
Abstract: The contribution of the epi-and endocardial as well as the myocardial electrical activity to the body surface potential was investigated in this study. A volume conductor including a realistic anisotropic ventricular model was built up and the forward problem of electrocardiography was solved for four different rhythms, in order to quantitatively describe the cardiac electrical contribution of each compartment of the heart. The results show, that the body surface potentials depend to a high degree on the epi-and endocardial electrical spread of excitation during the depolarization phase, whereas the influence of myocardial activity is more pronounced during repolarization. These findings indicate that the depolarization phase can be approximated by cardiac isotropic electrical.
BibTeX:
@inproceedings{Pfeifer2007b,
  author = {Bernhard Pfeifer and Michael Seger and Robert Modre-Osprian and Christoph Hintermuller and Dieter Hayn and Gunter Schreier and Bernhard Tilg},
  title = {Contributions of Epi-, Endo- and Myocardium to the Body Surface Potential},
  journal = {2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging},
  publisher = {IEEE},
  year = {2007},
  pages = {304--307},
  doi = {https://doi.org/10.1109/NFSI-ICFBI.2007.4387760}
}
Pfeifer, B., Seger, M., Hanser, F., Hintermüller, C., Fischer, G., Mühlthaler, H. and Tilg, B. A training whole-heart model for simulating propagation and ECG patterns 2007 Biomed. Signal Process. Control.
Vol. 2(4), pp. 323-330 
article DOI  
BibTeX:
@article{Pfeifer2007c,
  author = {Bernhard Pfeifer and Michael Seger and Friedrich Hanser and Christoph Hintermüller and Gerald Fischer and Hannes Mühlthaler and Bernhard Tilg},
  title = {A training whole-heart model for simulating propagation and ECG patterns},
  journal = {Biomed. Signal Process. Control.},
  year = {2007},
  volume = {2},
  number = {4},
  pages = {323--330},
  doi = {https://doi.org/10.1016/j.bspc.2007.06.002}
}
Pfeifer, B., Aschaber, J., Baumgartner, C., Dreiseitl, S., Modre, R., Schreier, G. and Tilg, B. A data warehouse for prostate cancer biomarker discovery 2007 International Conference on Bioinformatics & Computational Biology, BIOCOMP 2007, Volume II, June 25-28, 2007, Las Vegas Nevada, USA, pp. 323-327  inproceedings  
BibTeX:
@inproceedings{Pfeifer2007d,
  author = {Bernhard Pfeifer and Johannes Aschaber and Christian Baumgartner and Stephan Dreiseitl and Robert Modre and Günter Schreier and Bernhard Tilg},
  title = {A data warehouse for prostate cancer biomarker discovery},
  booktitle = {International Conference on Bioinformatics & Computational Biology, BIOCOMP 2007, Volume II, June 25-28, 2007, Las Vegas Nevada, USA},
  publisher = {CSREA Press},
  year = {2007},
  pages = {323--327}
}
Seger, M., Hintermüller, C., Fischer, G., Mühlthaler, H., Modre-Osprian, R., Tilg, B. and Pfeifer, B. AAM-based Segmentation for Imaging Cardiac Electrophysiology 2007
Vol. 46, pp. 36-42 
article DOI  
BibTeX:
@article{Seger2007,
  author = {M. Seger and C. Hintermüller and G. Fischer and H. Mühlthaler and R. Modre-Osprian and B. Tilg and B. Pfeifer},
  title = {AAM-based Segmentation for Imaging Cardiac Electrophysiology},
  year = {2007},
  volume = {46},
  pages = {36-42},
  doi = {https://doi.org/10.1055/s-0038-1627829}
}
Tilg, B., Pfeifer, B., Modre, R., Seger, M., Hintermuller, C., Fischer, G. and Hanser, F. Noninvasive Imaging of Cardiac Electrical Function: Achievements, Pitfalls and Limitations 2007 2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging, pp. 4-7  inproceedings DOI  
Abstract: We developed a noninvasive approach to image the electrical function in the human heart. By combining magnetic resonance (MR) imaging and body surface electrocardiographic (ECG) mapping the electrical activation sequence in the atrium and ventricle is reconstructed. The multi-channel ECG mapping data is acquired from the patients' chest. By coupling this data with the patients' anatomy, obtained from gated MR, and by solving a nonlinear ill-posed inverse problem we imaged the activation sequence. Clinical validation has been performed in 45 patients by comparing this noninvasive approach with catheter-mapping (CARTOTM) and conventional catheter techniques. This novel imaging approach aims at reconstructing focal and distributed electrical source patterns. We performed detailed clinical studies for sinus (normal and Wolff-Parkinson-White syndrome) and paced rhythm data. Besides the imaging of cardiac movement, perfusion and metabolism the imaging of electrical function will have a substantial clinical impact. Especially, in patients with focal atrial arrhythmias this method might become a powerful clinical diagnostic tool.
BibTeX:
@inproceedings{Tilg2007,
  author = {Bernhard Tilg and Bernhard Pfeifer and Robert Modre and Michael Seger and Christoph Hintermuller and Gerald Fischer and Friedrich Hanser},
  title = {Noninvasive Imaging of Cardiac Electrical Function: Achievements, Pitfalls and Limitations},
  journal = {2007 Joint Meeting of the 6th International Symposium on Noninvasive Functional Source Imaging of the Brain and Heart and the International Conference on Functional Biomedical Imaging},
  publisher = {IEEE},
  year = {2007},
  pages = {4--7},
  doi = {https://doi.org/10.1109/NFSI-ICFBI.2007.4387673}
}
Visvanathan, M., Breit, M., Pfeifer, B., Baumgartner, C., Modre-Osprian, R. and Tilg, B. Systematic analysis of signaling pathways using an integrative environment 2007 Methods of Information in Medicine
Vol. 46(3), pp. 386-391 
article DOI  
Abstract: Introduction: Understanding the biological processes of signaling pathways as a whole system requires an integrative software environment that has comprehensive capabilities. The environment should include tools for pathway design, visualization, simulation and a knowledge base concerning signaling pathways as one. In this paper we introduce a new integrative environment for the systematic analysis of signaling pathways. Methods: This system includes environments for pathway design, visualization, simulation and a knowledge base that combines biological and modeling information concerning signaling pathways that provides the basic understanding of the biological system, its structure and functioning. The system is designed with a client-server architecture. It contains a pathway designing environment and a simulation environment as upper layers with a relational knowledge base as the underlying layer. Results: The TNFα-mediated NF-κ signal transduction pathway model was designed and tested using our integrative framework. It was also useful to define the structure of the knowledge base. Sensitivity analysis of this specific pathway was performed providing simulation data. Then the model was extended showing promising initial results. Conclusion: The proposed system offers a holistic view of pathways containing biological and modeling data. It will help us to perform biological interpretation of the simulation results and thus contribute to a better understanding of the biological system for drug identification. © 2007 Schattauer GmbH.
BibTeX:
@article{Visvanathan2007,
  author = {Visvanathan, Mahesh and Breit, M. and Pfeifer, B. and Baumgartner, C. and Modre-Osprian, R. and Tilg, B.},
  title = {Systematic analysis of signaling pathways using an integrative environment},
  journal = {Methods of Information in Medicine},
  year = {2007},
  volume = {46},
  number = {3},
  pages = {386--391},
  doi = {https://doi.org/10.1160/ME0399}
}
Kugler, K., Tejada, M.M., Baumgartner, C., Tilg, B., Graber, A. and Pfeifer, B. Bridging Data Management and Knowledge Discovery in the Life Sciences 2008
Vol. 2, pp. 28-36 
article DOI  
BibTeX:
@article{Kugler2008,
  author = {Karl Kugler and Maria Mercedes Tejada and Christian Baumgartner and Bernhard Tilg and Armin Graber and Bernhard Pfeifer},
  title = {Bridging Data Management and Knowledge Discovery in the Life Sciences},
  year = {2008},
  volume = {2},
  pages = {28-36},
  doi = {https://doi.org/10.2174/1875036200802010028}
}
Mühlthaler, H., Quatember, B., Fraedrich, G., Mühlthaler, M., Pfeifer, B., Greiner, A. and Schocke, M.F.H. Quantification of blood flow velocity in stenosed arteries by the use of finite elements: an observer-independent noninvasive method. 2008 Magnetic resonance imaging
Vol. 26, pp. 1152-1159 
article DOI  
Abstract: Interventions for peripheral arterial disease should be designed to treat a physiological rather than an anatomic defect. Thus, for vascular surgeons, functional information about stenoses is as important as the anatomic one. In case of finding a stenosis by the use of magnetic resonance angiography, it would be a matter of particular interest to derive automatically and directly objective information about the hemodynamic influence on blood flow, caused by patient-specific stenoses. We developed a methodology to noninvasively perform numerical simulations of a patient's hemodynamic state on the basis of magnetic resonance images and by the means of the finite element method. We performed patient-specific three-dimensional simulation studies of the increase in systolic blood flow velocity due to stenoses using the commercial computational fluid dynamic software package FIDAP 8.52. The generation of a mesh defining the flow domain with a stenosis and some simulation results are shown.
BibTeX:
@article{Muehlthaler2008,
  author = {Mühlthaler, Hannes and Quatember, Bernhard and Fraedrich, Gustav and Mühlthaler, Markus and Pfeifer, Bernhard and Greiner, Andreas and Schocke, Michael F. H.},
  title = {Quantification of blood flow velocity in stenosed arteries by the use of finite elements: an observer-independent noninvasive method.},
  journal = {Magnetic resonance imaging},
  year = {2008},
  volume = {26},
  pages = {1152--1159},
  doi = {https://doi.org/10.1016/j.mri.2008.01.013}
}
Osl, M., Dreiseitl, S., Pfeifer, B., Weinberger, K., Klocker, H., Bartsch, G., Schäfer, G., Tilg, B., Graber, A. and Baumgartner, C. A new rule-based algorithm for identifying metabolic markers in prostate cancer using tandem mass spectrometry. 2008 Bioinformatics (Oxford, England)
Vol. 24, pp. 2908-2914 
article DOI  
Abstract: Prostate cancer is the most prevalent tumor in males and its incidence is expected to increase as the population ages. Prostate cancer is treatable by excision if detected at an early enough stage. The challenges of early diagnosis require the discovery of novel biomarkers and tools for prostate cancer management. We developed a novel feature selection algorithm termed as associative voting (AV) for identifying biomarker candidates in prostate cancer data measured via targeted metabolite profiling MS/MS analysis. We benchmarked our algorithm against two standard entropy-based and correlation-based feature selection methods [Information Gain (IG) and ReliefF (RF)] and observed that, on a variety of classification tasks in prostate cancer diagnosis, our algorithm identified subsets of biomarker candidates that are both smaller and show higher discriminatory power than the subsets identified by IG and RF. A literature study confirms that the highest ranked biomarker candidates identified by AV have independently been identified as important factors in prostate cancer development. The algorithm can be downloaded from the following http://biomed.umit.at/page.cfm?pageid=516.
BibTeX:
@article{Osl2008,
  author = {Osl, Melanie and Dreiseitl, Stephan and Pfeifer, Bernhard and Weinberger, Klaus and Klocker, Helmut and Bartsch, Georg and Schäfer, Georg and Tilg, Bernhard and Graber, Armin and Baumgartner, Christian},
  title = {A new rule-based algorithm for identifying metabolic markers in prostate cancer using tandem mass spectrometry.},
  journal = {Bioinformatics (Oxford, England)},
  year = {2008},
  volume = {24},
  pages = {2908--2914},
  doi = {https://doi.org/10.1093/bioinformatics/btn506}
}
Pfeifer, B. A Cellular Automaton Framework for Infectious Disease Spread Simulation 2008 The Open Medical Informatics Journal
Vol. 2(1), pp. 70-81 
article DOI URL 
Abstract: In this paper, a cellular automaton framework for processing the spatiotemporal spread of infectious diseases is presented. The developed environment simulates and visualizes how infectious diseases might spread, and hence provides a powerful instrument for health care organizations to generate disease prevention and contingency plans. In this study, the outbreak of an avian flu like virus was modeled in the state of Tyrol, and various scenarios such as quarantine, effect of different medications on viral spread and changes of social behavior were simulated.The proposed framework is implemented using the programming language Java. The set up of the simulation environment requires specification of the disease parameters and the geographical information using a population density colored map, enriched with demographic data.The results of the numerical simulations and the analysis of the computed parameters will be used to get a deeper understanding of how the disease spreading mechanisms work, and how to protect the population from contracting the disease. Strategies for optimization of medical treatment and vaccination regimens will also be investigated using our cellular automaton framework.In this study, six different scenarios were simulated. It showed that geographical barriers may help to slow down the spread of an infectious disease, however, when an aggressive and deadly communicable disease spreads, only quarantine and controlled medical treatment are able to stop the outbreak, if at all.
BibTeX:
@article{Pfeifer2008,
  author = {Pfeifer, Bernhard},
  title = {A Cellular Automaton Framework for Infectious Disease Spread Simulation},
  journal = {The Open Medical Informatics Journal},
  publisher = {Bentham Science Publishers Ltd.},
  year = {2008},
  volume = {2},
  number = {1},
  pages = {70--81},
  url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC2666960},
  doi = {https://doi.org/10.2174/1874431100802010070}
}
Pfeifer, B., Hanser, F., Seger, M., Fischer, G., Modre-Osprian, R. and Tilg, B. Patient-specific volume conductor modeling for non-invasive imaging of cardiac electrophysiology. 2008 The open medical informatics journal
Vol. 2(1), pp. 32-41 
article DOI URL 
Abstract: We propose a general workflow to numerically estimate the spread of electrical excitation in the patients' hearts. To this end, a semi-automatic segmentation pipeline for extracting the volume conductor model of structurally normal hearts is presented. The cardiac electrical source imaging technique aims to provide information about the spread of electrical excitation in order to assist the cardiologist in developing strategies for the treatment of cardiac arrhythmias. The volume conductor models of eight patients were extracted from cine-gated short-axis magnetic resonance imaging (MRI) data. The non-invasive estimation of electrical excitation was compared with the CARTO maps. The development of a volume conductor modeling pipeline for constructing a patient-specific volume conductor model in a fast and accurate way is one essential step to make the technique clinically applicable.
BibTeX:
@article{Pfeifer2008a,
  author = {Pfeifer, B. and Hanser, F. and Seger, M. and Fischer, G. and Modre-Osprian, R. and Tilg, B.},
  title = {Patient-specific volume conductor modeling for non-invasive imaging of cardiac electrophysiology.},
  journal = {The open medical informatics journal},
  publisher = {Bentham Science Publishers Ltd.},
  year = {2008},
  volume = {2},
  number = {1},
  pages = {32--41},
  url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC2666958},
  doi = {https://doi.org/10.2174/1874431100802010032}
}
Visvanathan, M., Breit, M., Pfeifer, B., Baumgartner, C., Modre-Osprian, R. and Tilg, B. DMSP--Database for Modeling Signaling Pathways. Combining biological and mathematical modeling knowledge for pathways. 2008 Methods of information in medicine
Vol. 47, pp. 140-148 
article  
Abstract: Presently, the protein interaction information concerning different signaling pathways is available in a qualitative manner in different online protein interaction databases. The challenge here is to derive a quantitative way of modeling signaling pathways from qualitative way of modeling signaling pathways from a qualitative level. To address this issue we developed a database that includes mathematical modeling knowledge and biological knowledge about different signaling pathways. The database is part of an integrative environment that includes environments for pathway design, visualization, simulation and a knowledge base that combines biological and modeling information concerning pathways. The system is designed as a client-server architecture. It contains a pathway designing environment and a simulation environment as upper layers with a relational knowledge base as the underlying layer. DMSP--Database for Modeling Signaling Pathways incorporates biological datasets from online databases like BIND, DIP, PIP, and SPiD. The modeling knowledge that has been incorporated is based on a literature study. Pathway models can be designed, visualized and simulated based on the knowledge stored in the DMSP. The user can download the whole dataset and build pathway models using the knowledge stored in our database. As an example, the TNFalpha pathway model was implemented and tested using this approach. DMSP is an initial step towards the aim of combining modeling and biological knowledge concerning signaling pathways. It helps in understanding pathways in a qualitative manner from a qualitative level. Simulation results enable the interpretation of a biological system from a quantitative and system-theoretic point of view.
BibTeX:
@article{Visvanathan2008,
  author = {Visvanathan, M. and Breit, M. and Pfeifer, B. and Baumgartner, C. and Modre-Osprian, R. and Tilg, B.},
  title = {DMSP--Database for Modeling Signaling Pathways. Combining biological and mathematical modeling knowledge for pathways.},
  journal = {Methods of information in medicine},
  year = {2008},
  volume = {47},
  pages = {140--148}
}
Wieser, L., Richter, H.E., Plank, G., Pfeifer, B., Tilg, B., Nowak, C.N. and Fischer, G. A finite element formulation for atrial tissue monolayer 2008 Methods of Information in Medicine
Vol. 47(2), pp. 131-139 
article DOI  
Abstract: Objectives: Using computer models for the study of complex atrial arrhythmias such as atrial fibrillation is computationally demanding as long observation periods in the order of tens of seconds are required. A well established approach for reducing computational workload is to approximate the thin atrial walls by curved monolayers. On the other hand, the finite element method (FEM) is a well established approach to solve the underlying partial differential equations. Methods: A generalized 2D finite element method (FEM) is presented which computes the corresponding stiffness and coupling matrix for arbitrarily shaped monolayers (ML). Compared to standard 2D FEM, only one additional coordinate transformation is required. This allows the use of existing FEM software with minor modifications. The algorithm was tested to simulate wave propagation in benchmark geometries and in a model of atrial anatomy. Results: The ML model was able to simulate electric activation in curved tissue with anisotropic conductivity. Simulations in branching tissue yielded slightly different patterns when compared to a volumetric model with finite thickness. In the model of atrial anatomy the computed activation times for five different pacing protocols displayed a correlation of 0.88 compared to clinical data. Conclusions: The presented method provides a useful and easily implemented approach to model wave propagation in MLs with a few restrictions to volumetric models. © 2008 Schattauer GmbH.
BibTeX:
@article{Wieser2008,
  author = {Wieser, Leonhard and Richter, H. E. and Plank, G. and Pfeifer, B. and Tilg, B. and Nowak, C. N. and Fischer, G.},
  title = {A finite element formulation for atrial tissue monolayer},
  journal = {Methods of Information in Medicine},
  year = {2008},
  volume = {47},
  number = {2},
  pages = {131--139},
  doi = {https://doi.org/10.3414/ME0414}
}
Netzer, M., Millonig, G., Osl, M., Pfeifer, B., Praun, S., Villinger, J., Vogel, W. and Baumgartner, C. A new ensemble-based algorithm for identifying breath gas marker candidates in liver disease using ion molecule reaction mass spectrometry. 2009 Bioinformatics (Oxford, England)
Vol. 25, pp. 941-947 
article DOI  
Abstract: Alcoholic fatty liver disease (AFLD) and non-AFLD (NAFLD) can progress to severe liver diseases such as steatohepatitis, cirrhosis and cancer. Thus, the detection of early liver disease is essential; however, minimal invasive diagnostic methods in clinical hepatology still lack specificity. Ion molecule reaction mass spectrometry (IMR-MS) was applied to a total of 126 human breath gas samples comprising 91 cases (AFLD, NAFLD and cirrhosis) and 35 healthy controls. A new feature selection modality termed Stacked Feature Ranking (SFR) was developed to identify potential liver disease marker candidates in breath gas samples, relying on the combination of different entropy- and correlation-based feature ranking methods including statistical hypothesis testing using a two-level architecture with a suggestion and a decision layer. We benchmarked SFR against four single feature selection methods, a wrapper and a recently described ensemble method, indicating a significantly higher discriminatory ability of up to 10-15% for the SFR selected gas compounds expressed by the area under the ROC curve (AUC) of 0.85-0.95. Using this approach, we were able to identify unexpected breath gas marker candidates in liver disease of high predictive value. A literature study further supports top-ranked markers to be associated with liver disease. We propose SFR as a powerful tool for biomarker search in breath gas and other biological samples using mass spectrometry. The algorithm SFR and IMR-MS datasets are available under http://biomed.umit.at/page.cfm?pageid=526.
BibTeX:
@article{Netzer2009,
  author = {Netzer, M. and Millonig, G. and Osl, M. and Pfeifer, B. and Praun, S. and Villinger, J. and Vogel, W. and Baumgartner, C.},
  title = {A new ensemble-based algorithm for identifying breath gas marker candidates in liver disease using ion molecule reaction mass spectrometry.},
  journal = {Bioinformatics (Oxford, England)},
  year = {2009},
  volume = {25},
  pages = {941--947},
  doi = {https://doi.org/10.1093/bioinformatics/btp093}
}
Osl, M., Dreiseitl, S., Cerqueira, F., Netzer, M., Pfeifer, B. and Baumgartner, C. Demoting redundant features to improve the discriminatory ability in cancer data. 2009 Journal of biomedical informatics
Vol. 42, pp. 721-725 
article DOI  
Abstract: The identification of a set of relevant but not redundant features is an important first step in building predictive and diagnostic models from biomedical data sets. Most commonly, individual features are ranked in terms of a quality criterion, out of which the best (first) k features are selected. However, feature ranking methods do not sufficiently account for interactions and correlations between the features. Thus, redundancy is likely to be encountered in the selected features. We present a new algorithm, termed Redundancy Demoting (RD), that takes an arbitrary feature ranking as input, and improves this ranking by identifying redundant features and demoting them to positions in the ranking in which they are not redundant. Redundant features are those that are correlated with other features and not relevant in the sense that they do not improve the discriminatory ability of a set of features. Experiments on two cancer data sets, one melanoma image data set and one lung cancer microarray data set, show that our algorithm greatly improves the feature rankings provided by the methods information gain, ReliefF and Student's t-test in terms of predictive power.
BibTeX:
@article{Osl2009,
  author = {Osl, M. and Dreiseitl, S. and Cerqueira, F. and Netzer, M. and Pfeifer, B. and Baumgartner, C.},
  title = {Demoting redundant features to improve the discriminatory ability in cancer data.},
  journal = {Journal of biomedical informatics},
  year = {2009},
  volume = {42},
  pages = {721--725},
  doi = {https://doi.org/10.1016/j.jbi.2009.05.006}
}
Visvanathan, M., Pfeifer, B., Baumgartner, C., Tilg, B. and Lushington, G.H. Integrative Approach for Combining TNFa-NFkB Mathematical Model to a Protein Interaction Connectivity Map 2009
Vol. 5542Bioinformatics Research and Applications, 5th International Symposium, ISBRA 2009, Fort Lauderdale, FL, USA, May 13-16, 2009, Proceedings, pp. 63-74 
inproceedings DOI URL 
BibTeX:
@inproceedings{Visvanathan2009,
  author = {Mahesh Visvanathan and Bernhard Pfeifer and Christian Baumgartner and Bernhard Tilg and Gerald H. Lushington},
  title = {Integrative Approach for Combining TNFa-NFkB Mathematical Model to a Protein Interaction Connectivity Map},
  booktitle = {Bioinformatics Research and Applications, 5th International Symposium, ISBRA 2009, Fort Lauderdale, FL, USA, May 13-16, 2009, Proceedings},
  publisher = {Springer},
  year = {2009},
  volume = {5542},
  pages = {63--74},
  url = {https://doi.org/10.1007/978-3-642-01551-9_7},
  doi = {https://doi.org/10.1007/978-3-642-01551-9%5C_7}
}
Visvanathan, M., Pfeifer, B., Baumgartner, C., Tilg, B. and Lushington, G.H. Integrative Approach for Combining TNFα-NFκB Mathematical Model to a Protein Interaction Connectivity Map 2009 , pp. 63-74  misc DOI  
BibTeX:
@misc{Visvanathan2009a,
  author = {Mahesh Visvanathan and Bernhard Pfeifer and Christian Baumgartner and Bernhard Tilg and Gerald Henry Lushington},
  title = {Integrative Approach for Combining TNFα-NFκB Mathematical Model to a Protein Interaction Connectivity Map},
  year = {2009},
  pages = {63-74},
  doi = {https://doi.org/10.1007/978-3-642-01551-9_7}
}
Baumgartner, C., Lewis, G.D., Netzer, M., Pfeifer, B. and Gerszten, R.E. A new data mining approach for profiling and categorizing kinetic patterns of metabolic biomarkers after myocardial injury. 2010 Bioinformatics (Oxford, England)
Vol. 26, pp. 1745-1751 
article DOI  
Abstract: The discovery of new and unexpected biomarkers in cardiovascular disease is a highly data-driven process that requires the complementary power of modern metabolite profiling technologies, bioinformatics and biostatistics. Clinical biomarkers of early myocardial injury are lacking. A prospective biomarker cohort study was carried out to identify, categorize and profile kinetic patterns of early metabolic biomarkers of planned myocardial infarction (PMI) and spontaneous (SMI) myocardial infarction. We applied a targeted mass spectrometry (MS)-based metabolite profiling platform to serial blood samples drawn from carefully phenotyped patients undergoing alcohol septal ablation for hypertrophic obstructive cardiomyopathy serving as a human model of PMI. Patients with SMI and patients undergoing catheterization without induction of myocardial infarction served as positive and negative controls to assess generalizability of markers identified in PMI. To identify metabolites of high predictive value in tandem mass spectrometry data, we introduced a new feature selection method for the categorization of metabolic signatures into three classes of weak, moderate and strong predictors, which can be easily applied to both paired and unpaired samples. Our paradigm outperformed standard null-hypothesis significance testing and other popular methods for feature selection in terms of the area under the receiver operating curve and the product of sensitivity and specificity. Our results emphasize that this new method was able to identify, classify and validate alterations of levels in multiple metabolites participating in pathways associated with myocardial injury as early as 10 min after PMI. The algorithm as well as supplementary material is available for download at: www.umit.at/page.cfm?vpath=departments/technik/iebe/tools/bi
BibTeX:
@article{Baumgartner2010,
  author = {Baumgartner, Christian and Lewis, Gregory D. and Netzer, Michael and Pfeifer, Bernhard and Gerszten, Robert E.},
  title = {A new data mining approach for profiling and categorizing kinetic patterns of metabolic biomarkers after myocardial injury.},
  journal = {Bioinformatics (Oxford, England)},
  year = {2010},
  volume = {26},
  pages = {1745--1751},
  doi = {https://doi.org/10.1093/bioinformatics/btq254}
}
Pfeifer, B. Biophysical Modeling using Cellular Automata 2010   misc DOI  
BibTeX:
@misc{Pfeifer,
  author = {Bernhard Pfeifer},
  title = {Biophysical Modeling using Cellular Automata},
  year = {2010},
  doi = {https://doi.org/10.5772/16071}
}
Pfeifer, B., Wurz, M., Hanser, F., Seger, M., Netzer, M., Osl, M., Modre-Osprian, R., Schreier, G. and Baumgartner, C. An epidemiological modeling and data integration framework. 2010 Methods of information in medicine
Vol. 49, pp. 290-296 
article DOI  
Abstract: In this work, a cellular automaton software package for simulating different infectious diseases, storing the simulation results in a data warehouse system and analyzing the obtained results to generate prediction models as well as contingency plans, is proposed. The Brisbane H3N2 flu virus, which has been spreading during the winter season 2009, was used for simulation in the federal state of Tyrol, Austria. The simulation-modeling framework consists of an underlying cellular automaton. The cellular automaton model is parameterized by known disease parameters and geographical as well as demographical conditions are included for simulating the spreading. The data generated by simulation are stored in the back room of the data warehouse using the Talend Open Studio software package, and subsequent statistical and data mining tasks are performed using the tool, termed Knowledge Discovery in Database Designer (KD3). The obtained simulation results were used for generating prediction models for all nine federal states of Austria. The proposed framework provides a powerful and easy to handle interface for parameterizing and simulating different infectious diseases in order to generate prediction models and improve contingency plans for future events.
BibTeX:
@article{Pfeifer2010,
  author = {Pfeifer, B. and Wurz, M. and Hanser, F. and Seger, M. and Netzer, M. and Osl, M. and Modre-Osprian, R. and Schreier, G. and Baumgartner, C.},
  title = {An epidemiological modeling and data integration framework.},
  journal = {Methods of information in medicine},
  year = {2010},
  volume = {49},
  pages = {290--296},
  doi = {https://doi.org/10.3414/ME09-02-0025}
}
Berger, T., Pfeifer, B., Hanser, F.F., Hintringer, F., Fischer, G., Netzer, M., Trieb, T., Stuehlinger, M., Dichtl, W., Baumgartner, C., Pachinger, O. and Seger, M. Single-beat noninvasive imaging of ventricular endocardial and epicardial activation in patients undergoing CRT 2011 PLoS ONE
Vol. 6(1) 
article DOI  
Abstract: Background: Little is known about the effect of cardiac resynchronization therapy (CRT) on endo- and epicardial ventricular activation. Noninvasive imaging of cardiac electrophysiology (NICE) is a novel imaging tool for visualization of both epi- and endocardial ventricular electrical activation. Methodology/Principal Findings: NICE was performed in ten patients with congestive heart failure (CHF) undergoing CRT and in ten patients without structural heart disease (control group). NICE is a fusion of data from high-resolution ECG mapping with a model of the patient's individual cardiothoracic anatomy created from magnetic resonance imaging. Beatto- beat endocardial and epicardial ventricular activation sequences were computed during native rhythm as well as during ventricular pacing using a bidomain theory-based heart model to solve the related inverse problem. During right ventricular (RV) pacing control patients showed a deterioration of the ventricular activation sequence similar to the intrinsic activation pattern of CHF patients. Left ventricular propagation velocities were significantly decreased in CHF patients as compared to the control group (1.6±0.4 versus 2.1±0.5 m/sec; p<0.05). CHF patients showed right-to-left septal activation with the latest activation epicardially in the lateral wall of the left ventricle. Biventricular pacing resulted in a resynchronization of the ventricular activation sequence and in a marked decrease of total LV activation duration as compared to intrinsic conduction and RV pacing (129±16 versus 157±28 and 173±25 ms; both p<0.05). Conclusions/Significance: Endocardial and epicardial ventricular activation can be visualized noninvasively by NICE. Identification of individual ventricular activation properties may help identify responders to CRT and to further improve response to CRT by facilitating a patient-specific lead placement and device programming. © 2011 Berger et al.
BibTeX:
@article{Berger2011,
  author = {Berger, Thomas and Pfeifer, Bernhard and Hanser, Friedrich F. and Hintringer, Florian and Fischer, Gerald and Netzer, Michael and Trieb, Thomas and Stuehlinger, Markus and Dichtl, Wolfgang and Baumgartner, Christian and Pachinger, Otmar and Seger, Michael},
  title = {Single-beat noninvasive imaging of ventricular endocardial and epicardial activation in patients undergoing CRT},
  journal = {PLoS ONE},
  year = {2011},
  volume = {6},
  number = {1},
  doi = {https://doi.org/10.1371/journal.pone.0016255}
}
Dander, A., Handler, M., Netzer, M., Pfeifer, B., Seger, M. and Baumgartner, C. [KD3] A Workflow-Based Application for Exploration of Biomedical Data Sets 2011 Trans. Large Scale Data Knowl. Centered Syst.
Vol. 4, pp. 148-157 
article DOI URL 
BibTeX:
@article{Dander2011,
  author = {Andreas Dander and Michael Handler and Michael Netzer and Bernhard Pfeifer and Michael Seger and Christian Baumgartner},
  title = {[KD3] A Workflow-Based Application for Exploration of Biomedical Data Sets},
  journal = {Trans. Large Scale Data Knowl. Centered Syst.},
  year = {2011},
  volume = {4},
  pages = {148--157},
  url = {https://doi.org/10.1007/978-3-642-23740-9_7},
  doi = {https://doi.org/10.1007/978-3-642-23740-9%5C_7}
}
Pfeifer, B Biophysical Modeling Using Cellular Automata 2011   book  
BibTeX:
@book{Pfeifer2011,
  author = {Pfeifer B},
  title = {Biophysical Modeling Using Cellular Automata},
  year = {2011}
}
Seger, M., Pfeifer, B. and Berger, T. Noninvasive Imaging of Cardiac Electrophysiology (NICE) 2011   misc DOI  
BibTeX:
@misc{Seger,
  author = {Michael Seger and Bernhard Pfeifer and Thomas Berger},
  title = {Noninvasive Imaging of Cardiac Electrophysiology (NICE)},
  year = {2011},
  doi = {https://doi.org/10.5772/30019}
}
Seger, M, Netzer, M, Hanser, F, Pfeifer, B, Dichtl, W, Stuehlinger, M, Trieb, T, Hintringer, F, Pachinger, O, Baumgartner, C and Berger, T Assessment of cardiac resynchronization therapy by non-invasive reconstruction of cardiac activation times 2011 Proc. 8th IASTED Int. Conf. on Biomedical Engineering, Innsbruck, Austria (Biomed2011),  conference  
BibTeX:
@conference{Seger2011,
  author = {Seger M, Netzer M, Hanser F, Pfeifer B, Dichtl W, Stuehlinger M, Trieb T, Hintringer F, Pachinger O, Baumgartner C, Berger T},
  title = {Assessment of cardiac resynchronization therapy by non-invasive reconstruction of cardiac activation times},
  booktitle = {Proc. 8th IASTED Int. Conf. on Biomedical Engineering, Innsbruck, Austria (Biomed2011),},
  year = {2011}
}
Seger, M., Netzer, M., Baumgartner, C., Hanser, F., Pfeifer, B., Berger, T., Hintringer, F., Pachinger, O., Dichtl, W., Stuehlinger, M. and Trieb, T. Assessment of Cardiac Resynchronization Therapy by Non-Invasive Reconstruction of Cardiac Activation Times 2011   misc DOI  
BibTeX:
@misc{Seger2011a,
  author = {Michael Seger and Michael Netzer and Christian Baumgartner and Friedrich Hanser and Bernhard Pfeifer and Thomas Berger and Florian Hintringer and Otmar Pachinger and Wolfgang Dichtl and Markus Stuehlinger and Thomas Trieb},
  title = {Assessment of Cardiac Resynchronization Therapy by Non-Invasive Reconstruction of Cardiac Activation Times},
  year = {2011},
  doi = {https://doi.org/10.2316/p.2011.723-154}
}
Seger, M, Pfeifer, B, (Pfeifer, B.T. and contributed equally) , S. Noninvasive Imaging of Cardiac Electrophysiology 2012   book  
BibTeX:
@book{Seger2012,
  author = {Seger M, Pfeifer B, Berger Th (Pfeifer, Seger contributed equally)},
  title = {Noninvasive Imaging of Cardiac Electrophysiology},
  publisher = {InTech Open Access Publisher},
  year = {2012}
}
Seger, M., Hanser, F., Dichtl, W., Stuehlinger, M., Hintringer, F., Trieb, T., Pfeifer, B. and Berger, T. Non-invasive imaging of cardiac electrophysiology in a cardiac resynchronization therapy defibrillator patient with a quadripolar left ventricular lead. 2014 Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
Vol. 16, pp. 743-749 
article DOI  
Abstract: The present study was aimed to assess epi- and endocardial ventricular electroanatomical activation during cardiac resynchronization therapy (CRT) by means of non-invasive imaging of cardiac electrophysiology (NICE) in a patient with a novel quadripolar LV lead. Non-invasive imaging of cardiac electrophysiology is a novel imaging tool which works by fusing data from high-resolution electrocardiogram (ECG) mapping with a model of the patient's individual cardiothoracic anatomy created from magnetic resonance imaging. This was performed in a cardiac resynchronization therapy defribrillator (CRT-D) patient with a quadripolar left ventricular (LV) lead. Beat-to-beat endocardial and epicardial ventricular activation sequences were computed using NICE during intrinsic conduction as well as during different pacing modes with different LV and biventricular (biV) pacing vectors. The spatial resolution of NICE enabled discrimination of the different pacing vectors during LV and biV pacing. Biventricular pacing resulted in a marked shortening of the total activation duration (TAD) of both ventricles when compared with intrinsic conduction and RV and LV pacing. Non-invasive imaging of cardiac electrophysiology facilitates non-invasive imaging of ventricular activation, which may be useful in CRT patients to locate the area of latest ventricular activation as the target area for LV lead placement. Moreover, especially in non-responders to CRT NICE may be further useful to determine the best electrical repositioning option.
BibTeX:
@article{Seger2014,
  author = {Seger, Michael and Hanser, Friedrich and Dichtl, Wolfgang and Stuehlinger, Markus and Hintringer, Florian and Trieb, Thomas and Pfeifer, Bernhard and Berger, Thomas},
  title = {Non-invasive imaging of cardiac electrophysiology in a cardiac resynchronization therapy defibrillator patient with a quadripolar left ventricular lead.},
  journal = {Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology},
  year = {2014},
  volume = {16},
  pages = {743--749},
  doi = {https://doi.org/10.1093/europace/euu045}
}
Barbieri, F., Pfeifer, B., Berger, T. and Dichtl, W. Comparison of conventional resynchronization therapy to multipoint pacing using two separate left ventricular leads by non-invasive imaging of cardiac electrophysiology. 2015 European heart journal
Vol. 36, pp. 3237 
article DOI  
BibTeX:
@article{Barbieri2015,
  author = {Barbieri, Fabian and Pfeifer, Bernhard and Berger, Thomas and Dichtl, Wolfgang},
  title = {Comparison of conventional resynchronization therapy to multipoint pacing using two separate left ventricular leads by non-invasive imaging of cardiac electrophysiology.},
  journal = {European heart journal},
  year = {2015},
  volume = {36},
  pages = {3237},
  doi = {https://doi.org/10.1093/eurheartj/ehv255}
}
Netzer, M, Handler, M, Pfeifer, B, Dander, A and Ch, B. Knowledge Discovery in Proteomic Mass Spectrometry Data 2015 Emerging Trends in Computational Biology, Bioinformatics and Systems Biology  article  
BibTeX:
@article{Netzer2015,
  author = {Netzer M, Handler M, Pfeifer B, Dander A, Baumgartner Ch},
  title = {Knowledge Discovery in Proteomic Mass Spectrometry Data},
  journal = {Emerging Trends in Computational Biology, Bioinformatics and Systems Biology},
  year = {2015}
}
Netzer, M., Handler, M., Pfeifer, B., Dander, A. and Baumgartner, C. Knowledge Discovery in Proteomic Mass Spectrometry Data 2015 , pp. 503-519  misc DOI  
BibTeX:
@misc{Netzer2015a,
  author = {Michael Netzer and Michael Handler and Bernhard Pfeifer and Andreas Dander and Christian Baumgartner},
  title = {Knowledge Discovery in Proteomic Mass Spectrometry Data},
  year = {2015},
  pages = {503-519},
  doi = {https://doi.org/10.1016/b978-0-12-802508-6.00028-4}
}
Barbieri, F., Senoner, T., Adukauskaite, A., Dobner, S., Holfeld, J., Semsroth, S., Lambert, T., Zweiker, D., Theurl, T., Rainer, P.P., Schmidt, A., Feuchtner, G.M., Steinwender, C., Hoppe, U.C., Hintringer, F., Bauer, A., Müller, S., Grimm, M., Pfeifer, B.E. and Dichtl, W. Long-Term Prognostic Value of High-Sensitivity Troponin T Added to N-Terminal Pro Brain Natriuretic Peptide Plasma Levels Before Valve Replacement for Severe Aortic Stenosis. 2019 The American journal of cardiology
Vol. 124, pp. 1932-1939 
article DOI  
Abstract: Natriuretic peptide plasma levels help to manage patients with severe aortic stenosis (AS). The role of troponin plasma levels in this patient cohort remains speculative. A consortium of 4 university hospital centers in Austria analyzed retrospectively 3,595 patients admitted for valve replacement because of severe AS since 2007. The aim was to compare the additive preprocedural value of high-sensitivity troponin T (hsTnT) to N-terminal pro brain natriuretic peptide (NT-proBNP) plasma levels in predicting postoperative long-term survival in a large cohort undergoing either surgical (57.8%) or transcatheter (42.2%) aortic valve replacement. During a median follow-up of 2.93 (1.91 to 4.92) years, 919 patients (25.6%) died, in them 556 (15.5%) due to cardiovascular causes. Both normal hsTnT (<14 ng/l) and NT-proBNP (within age- and sex-corrected normal range) plasma levels were found in 481 patients (14.3%, group 1). Normal hsTnT but elevated NT-proBNP plasma levels were found in 748 patients (22.3%, group 2). Elevated hsTnT but normal NT-proBNP plasma levels were found in 258 patients (7.7%, group 3). Both elevated hsTnT and elevated NT-proBNP plasma levels were found in 1,869 patients (55.7%, group 4). Using Log Rank tests for comparison there was a highly significant difference in both cardiovascular mortality (p <0.0001) and all-cause mortality (p <0.0001). All-cause mortality rates after 1, 3, and 5 years were 2.1%, 5.4%, 7.7% in group 1; 4.0%, 7.5%, 11.5% in group 2; 5.8%, 8.9%, 14.0% in group 3; and 12.3%, 22.6%, 28.4% in group 4. In conclusion, hsTnT adds additional impact to NT-proBNP as a routinely available biomarker for risk stratification concerning postoperative survival in patients with severe AS admitted for valve replacement. The present study supports the concept to integrate hsTnT plasma levels in the management of severe AS.
BibTeX:
@article{Barbieri2019,
  author = {Barbieri, Fabian and Senoner, Thomas and Adukauskaite, Agne and Dobner, Stephan and Holfeld, Johannes and Semsroth, Severin and Lambert, Thomas and Zweiker, David and Theurl, Thomas and Rainer, Peter Paul and Schmidt, Albrecht and Feuchtner, Gudrun Maria and Steinwender, Clemens and Hoppe, Uta Charlotte and Hintringer, Florian and Bauer, Axel and Müller, Silvana and Grimm, Michael and Pfeifer, Bernhard Erich and Dichtl, Wolfgang},
  title = {Long-Term Prognostic Value of High-Sensitivity Troponin T Added to N-Terminal Pro Brain Natriuretic Peptide Plasma Levels Before Valve Replacement for Severe Aortic Stenosis.},
  journal = {The American journal of cardiology},
  year = {2019},
  volume = {124},
  pages = {1932--1939},
  doi = {https://doi.org/10.1016/j.amjcard.2019.09.014}
}
Senoner, T., Barbieri, F., Semmler, G., Adukauskaite, A., Rubatscher, A., Schgör, W., Stühlinger, M., Bauer, A., Pfeifer, B.E., Fiedler, L., Roithinger, F.X., Hintringer, F., Suessenbacher, A., Wollmann, C.G. and Dichtl, W. Long-term performance of an atrial lead capable of accelerometer based detection of cardiac contractility in patients receiving cardiac resynchronisation therapy 2019 PLoS ONE
Vol. 14(9) 
article DOI  
Abstract: Objectives To evaluate the long-term performance of the SonRtip atrial lead. Background To optimize atrioventricular and interventricular timing and thereby potentially improving cardiac resynchronization therapy (CRT) responder rates, a lead integrated technology and a cardioverter/defibrillator-based algorithm measuring peak endocardial acceleration have been introduced. Long-term performance of the atrial lead (SonRtip PS55D, Sorin/MicroPort CRM, Italy) embedded with such a sensor has not been reported so far. Methods Between 2012 and 2018, 143 patients underwent implantation of the SonRtip atrial lead in four Austrian medical centers. Conventional bipolar atrial leads implanted during the same period in 526 patients receiving CRT were used as control cohort. Results Among 669 patients included in the study, 10 (1.5%) showed increased atrial pacing thresholds and/or decreased atrial sensing amplitudes and/or sudden increase in atrial lead impedance (above 3000 Ω) after an uneventful early postoperative period. Seven (70%) of the malfunctioning leads were SonRtip leads (p <0.001). Lead replacement was needed in 4.2% of SonRtip leads (six out of 143) and in 0.38% of all other conventional atrial leads (two out of 526) (p <0.001). Because of unaltered atrial sensing properties, a wait and see strategy was chosen in two patients-one of them with a SonRtip lead. The implanted atrial lead in the latter person experienced a sudden increase in pacing threshold (4V/0.35ms). Conclusions While short-term safety and stable technical performance of the SonRtip atrial lead could be confirmed, our study found an unexpectedly high malfunction rate over a longer follow-up period.
BibTeX:
@article{Senoner2019,
  author = {Senoner, Thomas and Barbieri, Fabian and Semmler, Georg and Adukauskaite, Agne and Rubatscher, Andrea and Schgör, Wilfried and Stühlinger, Markus and Bauer, Axel and Pfeifer, Bernhard Erich and Fiedler, Lukas and Roithinger, Franz Xaver and Hintringer, Florian and Suessenbacher, Alois and Wollmann, Christian Georg and Dichtl, Wolfgang},
  title = {Long-term performance of an atrial lead capable of accelerometer based detection of cardiac contractility in patients receiving cardiac resynchronisation therapy},
  journal = {PLoS ONE},
  publisher = {Public Library of Science},
  year = {2019},
  volume = {14},
  number = {9},
  doi = {https://doi.org/10.1371/journal.pone.0222269}
}
Barbieri, F., Adukauskaite, A., Senoner, T., Rubatscher, A., Schgör, W., Stühlinger, M., Pfeifer, B.E., Bauer, A., Hintringer, F. and Dichtl, W. Supplemental dataset on the influence of cardiac resynchronisation therapy in pacing-induced cardiomyopathy and concomitant central sleep Apnea. 2020 Data in brief
Vol. 33, pp. 106461-106461 
article DOI URL 
Abstract: This article contains supplemental data to the publication "Central Sleep Apnea and Pacing-Induced Cardiomyopathy" [1], which was the most recent publication of the "UPGRADE" study. It provides in-depth analysis of the effects of cardiac resynchronisation therapy (CRT) in patients suffering from pacing-induced cardiomyopathy (PICM) on cardiac remodeling as well as functional cardiac parameters in comparison to continuous right ventricular pacing (RVP). Furthermore, it also covers additional data on several sleep parameters, which were not presented in the main article including the index for obstructive sleep apnea (OSA), the index for mixed sleep apnea and the oxygen saturation measurements during polysomnography. Further, Kaplan-Meier curves are presented for major adverse cardiac events (MACE) and overall mortality by severity of sleep apnea. Generally, the "UGRADE" study was a single-center prospective double-blinded randomized controlled trial lasting from 2014 to 2020. The methodology included a cross-over design giving the possibility to detect differences while CRT was activated and while continuous RVP was applied. The presented data should aid clinicians in daily practice as upgrading to CRT is not limited to improvement in cardiac parameters, but also modifies sleep apnea in patients with PICM, a generally sparsely studied entity of heart failure.
BibTeX:
@article{Barbieri2020,
  author = {Barbieri, Fabian and Adukauskaite, Agne and Senoner, Thomas and Rubatscher, Andrea and Schgör, Wilfried and Stühlinger, Markus and Pfeifer, Bernhard Erich and Bauer, Axel and Hintringer, Florian and Dichtl, Wolfgang},
  title = {Supplemental dataset on the influence of cardiac resynchronisation therapy in pacing-induced cardiomyopathy and concomitant central sleep Apnea.},
  journal = {Data in brief},
  publisher = {Elsevier Inc.},
  year = {2020},
  volume = {33},
  pages = {106461--106461},
  url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC7689044},
  doi = {https://doi.org/10.1016/j.dib.2020.106461}
}
Barbieri, F., Senoner, T., Adukauskaite, A., Dobner, S., Holfeld, J., Semsroth, S., Lambert, T., Zweiker, D., Theurl, T., Rainer, P., Schmidt, A., Feuchtner, G., Steinwender, C., Hoppe, U., Hintringer, F., Bauer, A., Müller, S., Grimm, M., Pfeifer, B. and Dichtl, W. Dataset on the prognostic value of cardiac biomarkers used in clinical routine in patients with severe aortic stenosis undergoing valve replacement. 2020 Data in brief
Vol. 29, pp. 105111-105111 
article DOI URL 
Abstract: Hereby, the supplemental data of the research article "Long-Term Prognostic Value of High-Sensitivity Troponin T added to N-Terminal Pro Brain Natriuretic Peptide Plasma Levels before Valve Replacement for Severe Aortic Stenosis" are presented [1]. It offers enhanced input on the predictive value of these biomarkers considering the influence of the presence of concomitant coronary artery disease (CAD) in various severities as well as an additional cox proportional hazard model on cardiovascular mortality. Furthermore, the receiver operating characteristic (ROC) curves are shown as figures. The material described increases therefore the understanding of the predictive value of these already routinely available biomarkers and reduces the risk of potential bias due to possible confounding factors. It also underlines the urge for a multi-factorial approach in diagnostics to detect the optimal point for referral to valve replacement other than just symptomatic status, an observed reduction in left ventricular ejection fraction or the presence of CAD with the necessity for coronary artery bypass grafting (CABG) [2]. The data of the 3595 patients were gathered retrospectively at a consortium of four university hospital centers in Austria and combined with prospectively collected data on cardiovascular and all-cause mortality.
BibTeX:
@article{Barbieri2020a,
  author = {Barbieri, Fabian and Senoner, Thomas and Adukauskaite, Agne and Dobner, Stephan and Holfeld, Johannes and Semsroth, Severin and Lambert, Thomas and Zweiker, David and Theurl, Thomas and Rainer, Peter and Schmidt, Albrecht and Feuchtner, Gudrun and Steinwender, Clemens and Hoppe, Uta and Hintringer, Florian and Bauer, Axel and Müller, Silvana and Grimm, Michael and Pfeifer, Bernhard and Dichtl, Wolfgang},
  title = {Dataset on the prognostic value of cardiac biomarkers used in clinical routine in patients with severe aortic stenosis undergoing valve replacement.},
  journal = {Data in brief},
  publisher = {Elsevier Inc.},
  year = {2020},
  volume = {29},
  pages = {105111--105111},
  url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC6971345},
  doi = {https://doi.org/10.1016/j.dib.2020.105111}
}
Eggerth, A., Kreiner, K., Hayn, D., Pfeifer, B., Pölzl, G., Egelseer-Bründl, T. and Schreier, G. Natural language processing for detecting medication-related notes in heart failure telehealth patients 2020 Studies in Health Technology and Informatics
Vol. 270, pp. 761-765 
inproceedings DOI URL 
Abstract: Heart Failure is a severe chronic disease of the heart. Telehealth networks implement closed-loop healthcare paradigms for optimal treatment of the patients. For comprehensive documentation of medication treatment, health professionals create free text collaboration notes in addition to structured information. To make this valuable source of information available for adherence analyses, we developed classifiers for automated categorization of notes based on natural language processing, which allows filtering of relevant entries to spare data analysts from tedious manual screening. Furthermore, we identified potential improvements of the queries for structured treatment documentation. For 3,952 notes, the majority of the manually annotated category tags was medication-related. The highest F1-measure of our developed classifiers was 0.90. We conclude that our approach is a valuable tool to support adherence research based on datasets containing free-text entries.
BibTeX:
@inproceedings{Eggerth2020,
  author = {Eggerth, Alphons and Kreiner, Karl and Hayn, Dieter and Pfeifer, Bernhard and Pölzl, Gerhard and Egelseer-Bründl, Tim and Schreier, Günter},
  title = {Natural language processing for detecting medication-related notes in heart failure telehealth patients},
  journal = {Studies in Health Technology and Informatics},
  publisher = {IOS Press},
  year = {2020},
  volume = {270},
  pages = {761--765},
  url = {https://pubmed.ncbi.nlm.nih.gov/32570485/},
  doi = {https://doi.org/10.3233/SHTI200263}
}
Engler, C., Leo, M., Pfeifer, B., Juchum, M., Chen-Koenig, D., Poelzl, K., Schoenherr, H., Vill, D., Oberdanner, J., Eisendle, E., Middeldorf, K., Heindl, B., Gaenzer, H., Bode, G., Kirchmeyr, K., Ladner, G., Rieger, L., Koellensperger, U., Schwaiger, A., Stoeckl, F., Zangerl, G., Lechleitner, M., Delmarko, I., Oberaigner, W., Rissbacher, C., Tilg, H. and Ebenbichler, C. Long-term trends in the prescription of antidiabetic drugs: real-world evidence from the Diabetes Registry Tyrol 2012-2018. 2020 BMJ open diabetes research & care
Vol. 8 
article DOI  
Abstract: Prescription patterns of antidiabetic drugs in the period from 2012 to 2018 were investigated based on the Diabetes Registry Tyrol. To validate the findings, we compared the numbers with trends of different national registries conducted in a comparable period of time. Medication data, prescription patterns, age groups, antidiabetic therapies and quality parameters (hemoglobin A1c, body mass index, complications) of 10 875 patients with type 2 diabetes from 2012 to 2018 were retrospectively assessed and descriptively analyzed. The changes were assessed using a time series analysis with linear regression and prescription trends were plotted over time. Sodium/glucose cotransporter 2 inhibitors (SGLT-2i) showed a significant increase in prescription from 2012 to 2018 (p<0.001), as well as metformin (p=0.002), gliptins (p=0.013) and glucagon-like peptide-1 agonists (GLP-1a) (p=0.017). Significant reduction in sulfonylurea prescriptions (p<0.001) was observed. Metformin was the most frequently prescribed antidiabetic drug (51.3%), followed by insulin/analogs (34.6%), gliptins (28.2%), SGLT-2i (11.7%), sulfonylurea (9.1%), glitazones (3.7%), GLP-1a (2.8%) and glucosidase inhibitors (0.4%). In this long-term, real-world study on prescription changes in the Diabetes Registry Tyrol, we observed significant increase in SGLT-2i, metformin, gliptins and GLP-1a prescriptions. In contrast prescriptions for sulfonylureas declined significantly. Changes were consistent over the years 2012-2018. Changes in prescription patterns occurred even before the publication of international and national guidelines. Thus, physicians change their prescription practice not only based on published guidelines, but even earlier on publication of cardiovascular outcome trials.
BibTeX:
@article{Engler2020,
  author = {Engler, Clemens and Leo, Marco and Pfeifer, Bernhard and Juchum, Martin and Chen-Koenig, Di and Poelzl, Karin and Schoenherr, Hans and Vill, David and Oberdanner, Juliana and Eisendle, Egon and Middeldorf, Klaus and Heindl, Bernhard and Gaenzer, Hannes and Bode, Gerald and Kirchmeyr, Karl and Ladner, Guenther and Rieger, Lisa and Koellensperger, Ursula and Schwaiger, Andrea and Stoeckl, Florian and Zangerl, Guenther and Lechleitner, Monika and Delmarko, Irmgard and Oberaigner, Wilhelm and Rissbacher, Clemens and Tilg, Herbert and Ebenbichler, Christoph},
  title = {Long-term trends in the prescription of antidiabetic drugs: real-world evidence from the Diabetes Registry Tyrol 2012-2018.},
  journal = {BMJ open diabetes research & care},
  year = {2020},
  volume = {8},
  doi = {https://doi.org/10.1136/bmjdrc-2020-001279}
}
Lauschensky, A., Hayn, D., Eggerth, A., Modreosprian, R., Pfeifer, B., Egelseer-Bründl, T., Pölzl, G. and Schreier, G. Concept for visualisation of guideline adherence of medication prescriptions in a heart failure telehealth system 2020 Studies in Health Technology and Informatics
Vol. 271, pp. 49-56 
inproceedings DOI  
Abstract: Background: Heart failure is a chronic disease that affects around 26 million people worldwide. Projections assume a substantial increase in prevalence over the next years. To improve the survival rate and quality of life in patients suffering from heart failure, the European Society of Cardiology published guidelines for diagnosis and treatment. Adherence of healthcare professionals' medication prescriptions with regard to these guidelines is critical for optimal outcomes. Methods: Data from the conceptional phase of the existing disease management network 'HerzMobil Tirol' were analysed. Prescriptions and patient-reported intake data of the four major substances of recommended heart failure medication were used to calculate the relative prescribed doses as a percentage of the recommended target doses. A concept for visualisation of the prescription status was developed in cooperation with health professionals. Results: The documented prescriptions were analysed and used to develop a mock-up in order to visualise the prescription status for the individual patient. Conclusion: Analysis and visualisation can be managed by displaying the calculated daily relative dose per substance group in a traffic light system.
BibTeX:
@inproceedings{Lauschensky2020,
  author = {Lauschensky, Aaron and Hayn, Dieter and Eggerth, Alphons and Modreosprian, Robert and Pfeifer, Bernhard and Egelseer-Bründl, Tim and Pölzl, Gerhard and Schreier, Günter},
  title = {Concept for visualisation of guideline adherence of medication prescriptions in a heart failure telehealth system},
  journal = {Studies in Health Technology and Informatics},
  publisher = {IOS Press BV},
  year = {2020},
  volume = {271},
  pages = {49--56},
  doi = {https://doi.org/10.3233/SHTI200073}
}
Niederseer, D., Rossi, V.A., Barbieri, F., Schmied, C.M., Bohm, P., Pfeifer, B., Wernly, B., Dichtl, W., Sthlinger, M., Hintringer, F. and Berger, T. Repolarisation in patients with ischaemic and nonischaemic cardiomyopathy: assessment of parameters of transmural dispersion of repolarisation using the 65-lead surface ECG 2020 Cardiovasc Med. 2020;23:w02129  article DOI  
BibTeX:
@article{Niederseer,
  author = {David Niederseer and Valentina A. Rossi and Fabian Barbieri and Christian M. Schmied and Philipp Bohm and Bernhard Pfeifer and Bernhard Wernly and Wolfgang Dichtl and Markus Sthlinger and Florian Hintringer and Thomas Berger},
  title = {Repolarisation in patients with ischaemic and nonischaemic cardiomyopathy: assessment of parameters of transmural dispersion of repolarisation using the 65-lead surface ECG},
  journal = {Cardiovasc Med. 2020;23:w02129},
  year = {2020},
  doi = {https://doi.org/10.4414/cvm.2020.02129}
}
Pfeifer, B., Modre-Osprian, R., Kastner, P., Hanser, F., Rissbacher, C. and Baumgarten, D. A computer model for patient individual parametrizing of ventricular tachycardia termination algorithms 2020 Studies in Health Technology and Informatics
Vol. 271, pp. 215-223 
inproceedings DOI  
Abstract: Background: Antitachycardial pacing (ATP) is a painless method for terminating ventricular tachycardias (VT) which would otherwise be treated using a painful high energy shock. However, it is well known that not each VT can be successfully terminated by ATP. Furthermore, ATP can be parametrized in several ways using scan, ramp or scan ramp approaches and can be applied in the right ventricle or in both ventricles (biventricular). In this work, we investigate the therapeutically most convenient ATP protocol based on a computer simulation using a patient individual model. Methods: A patient individual model generated from a 3D/4D data set and a hybrid automaton was used for modeling and simulation of different VT scenarios. On the different VTs (from cycle length 288 ms up to 408 ms) different ATP approaches derived from the ADVANCE-CRT trial were applied in order to determine the effectiveness of these approaches. Results: In this computer simulation study we were able to verify and validate the results from the ADVANCE-CRT trial. Biventricular ATP does not prove to be more effective than RV ATP but has a slight advantage in terminating fast VTs. Conclusions: The availability of a patient individual model and knowledge about the ischemic area and the underlying mechanism of the VTs will allow the use of these models to optimize ATP management.
BibTeX:
@inproceedings{Pfeifer2020,
  author = {Pfeifer, Bernhard and Modre-Osprian, Robert and Kastner, Peter and Hanser, Friedrich and Rissbacher, Clemens and Baumgarten, Daniel},
  title = {A computer model for patient individual parametrizing of ventricular tachycardia termination algorithms},
  journal = {Studies in Health Technology and Informatics},
  publisher = {IOS Press BV},
  year = {2020},
  volume = {271},
  pages = {215--223},
  doi = {https://doi.org/10.3233/SHTI200099}
}
Wiesmüller, F., Eggerth, A., Kreiner, K., Hayn, D., Hanke, S., Pfeifer, B., Pölzl, G., Egelseer-Bründl, T. and Schreier, G. Automated Extraction of Time References From Clinical Notes in a Heart Failure Telehealth Network 2020 Computing in Cardiology, CinC 2020, Rimini, Italy, September 13-16, 2020, pp. 1-4  inproceedings DOI  
BibTeX:
@inproceedings{Wiesmueller2020,
  author = {Fabian Wiesmüller and Alphons Eggerth and Karl Kreiner and Dieter Hayn and Sten Hanke and Bernhard Pfeifer and Gerhard Pölzl and Tim Egelseer-Bründl and Günter Schreier},
  title = {Automated Extraction of Time References From Clinical Notes in a Heart Failure Telehealth Network},
  booktitle = {Computing in Cardiology, CinC 2020, Rimini, Italy, September 13-16, 2020},
  publisher = {IEEE},
  year = {2020},
  pages = {1--4},
  doi = {https://doi.org/10.22489/CinC.2020.186}
}
Barbieri, F., Adukauskaite, A., Heidbreder, A., Brandauer, E., Bergmann, M., Stefani, A., Holzknecht, E., Senoner, T., Rubatscher, A., Schgör, W., Stühlinger, M., Pfeifer, B.E., Bauer, A., Hintringer, F., Högl, B. and Dichtl, W. Central Sleep Apnea and Pacing-Induced Cardiomyopathy 2021 American Journal of Cardiology
Vol. 139, pp. 97-104 
article DOI  
Abstract: The role of central sleep apnea (CSA) in pacing-induced cardiomyopathy (PICM) remains speculative. In a prospective trial entitled UPGRADE, the presence of CSA was assessed by single-night polysomnography (PSG) in 54 PICM patients within 1 month after left ventricular lead implantation (with biventricular stimulation still not activated). CSA was diagnosed in half of patients (n = 27). Patients with moderate or severe CSA were randomized to cardiac resynchronization therapy (CRT) versus right ventricular pacing (RVP) in a double-blinded cross-over design and re-scheduled for a follow-up PSG within 3 to 5 months. After crossing-over of stimulation mode another PSG was conducted 3 to 5 months later. CRT led to a significant increase in left ventricular ejection fraction and significant reduction in left ventricular end systolic volumes and N-terminal pro brain natriuretic peptide plasma levels, whereas no significant effects were observed with ongoing RVP. CSA was significantly improved after 3.9 (3.2 to 4.4) months of CRT: apnea-hypopnea index decreased from 39.1 (32.1 to 54.0) events per hour at baseline to 22.2/h (10.9 to 36.7) by CRT (p <0.001). Central apnea index decreased from 27.1/h (17.7 to 36.1) at baseline to 6.8/h (1.1 to 14.4) after CRT activation (p <0.001). Ongoing RVP yielded only a minor improvement in apnea-hypopnea index and central apnea index. Pre-existent CSA did not affect structural response rate and had no impact on mid-term follow-up (median 2.8 years). In conclusion, CSA is highly prevalent in patients with PICM. CRT upgrading significantly improves CSA leading to a similar outcome in PICM patients without pre-existent CSA.
BibTeX:
@article{Barbieri2021,
  author = {Barbieri, Fabian and Adukauskaite, Agne and Heidbreder, Anna and Brandauer, Elisabeth and Bergmann, Melanie and Stefani, Ambra and Holzknecht, Evi and Senoner, Thomas and Rubatscher, Andrea and Schgör, Wilfried and Stühlinger, Markus and Pfeifer, Bernhard Erich and Bauer, Axel and Hintringer, Florian and Högl, Birgit and Dichtl, Wolfgang},
  title = {Central Sleep Apnea and Pacing-Induced Cardiomyopathy},
  journal = {American Journal of Cardiology},
  publisher = {Elsevier Inc.},
  year = {2021},
  volume = {139},
  pages = {97--104},
  doi = {https://doi.org/10.1016/j.amjcard.2020.09.027}
}
El Moazen, G., Pfeifer, B., Loid, A., Kastner, P. and Ciardi, C. The Effectiveness of Telemedical Monitoring Program DiabCare Tirol for Patients with Gestational Diabetes Mellitus. 2021 Studies in health technology and informatics
Vol. 285, pp. 205-210 
article DOI  
Abstract: The aim of this paper was to evaluate the effect of telemedical care of gestational diabetes mellitus (GDM) patients with the digital treatment pathway model DiabCare Tirol. 27 courses of patients with GDM, who were telemonitored through the integrated care program DiabCare Tirol in a diabetes outpatient clinic in Tyrol, Austria during the COVID-19 pandemic in 2020, were analyzed. In addition, randomized controlled trials (RCTs) on telemedicine interventions for GDM were researched, and their results were used for comparison with this disease management method. The patient outcome analysis was used to examine the effects of the integrated care program involving telemonitoring support and compared them to the results of RCTs in which participants were randomly assigned to one of two groups, either mobile monitored or standard treatment group. The feasibility of the digital treatment pathway model was confirmed in practice, as the trend analysis of the 27 GDM patients involved showed significantly improved glycaemic control. Results of RCT studies tend to support the findings of DiabCare Tirol. Benefits of telemonitoring with integrated care to support conventional therapy cannot be dismissed, especially in times of the pandemic. Continuous outcome research with larger patient numbers will be necessary to confirm the effectiveness of telemonitoring in a regular care setting.
BibTeX:
@article{ElMoazen2021,
  author = {El Moazen, Gihan and Pfeifer, Bernhard and Loid, Agnes and Kastner, Peter and Ciardi, Christian},
  title = {The Effectiveness of Telemedical Monitoring Program DiabCare Tirol for Patients with Gestational Diabetes Mellitus.},
  journal = {Studies in health technology and informatics},
  year = {2021},
  volume = {285},
  pages = {205--210},
  doi = {https://doi.org/10.3233/SHTI210599}
}
Poelzl, G., Egelseer-Bruendl, T., Pfeifer, B., Modre-Osprian, R., Welte, S., Fetz, B., Krestan, S., Haselwanter, B., Zaruba, M.M., Doerler, J., Rissbacher, C., Ammenwerth, E. and Bauer, A. Feasibility and effectiveness of a multidimensional post-discharge disease management programme for heart failure patients in clinical practice: the HerzMobil Tirol programme. 2021 Clinical research in cardiology : official journal of the German Cardiac Society  article DOI  
Abstract: It remains unclear whether transitional care management outside of a clinical trial setting provides benefits for patients with acute heart failure (AHF) after hospitalization. We evaluated the feasibility and effectiveness of a multidimensional post-discharge disease management programme using a telemedical monitoring system incorporated in a comprehensive network of heart failure nurses, resident physicians, and secondary and tertiary referral centres (HerzMobil Tirol, HMT), METHODS AND RESULTS: The non-randomized study included 508 AHF patients that were managed in HMT (n = 251) or contemporaneously in usual care (UC, n = 257) after discharge from hospital from 2016 to 2019. Groups were retrospectively matched for age and sex. The primary endpoint was time to HF readmission and all-cause mortality within 6 months. Multivariable Cox proportional hazard models were used to assess the effectiveness. The primary endpoint occurred in 48 patients (19.1%) in HMT and 89 (34.6%) in UC. Compared with UC, management by HMT was associated with a 46%-reduction in the primary endpoint (adjusted HR 0.54; 95% CI 0.37-0.77; P < 0.001). Subgroup analyses revealed consistent effectiveness. The composite of recurrent HF hospitalization and death within 6 months per 100 patient-years was 64.2 in HMT and 108.2 in UC (adjusted HR 0.41; 95% CI 0.29-0.55; P < 0.001 with death considered as a competing risk). After 1 year, 25 (10%) patients died in HMT compared with 66 (25.7%) in UC (HR 0.38; 95% CI 0.23-0.61, P < 0.001). A multidimensional post-discharge disease management programme, comprising a telemedical monitoring system incorporated in a comprehensive network of specialized heart failure nurses and resident physicians, is feasible and effective in clinical practice.
BibTeX:
@article{Poelzl2021,
  author = {Poelzl, G. and Egelseer-Bruendl, T. and Pfeifer, B. and Modre-Osprian, R. and Welte, S. and Fetz, B. and Krestan, S. and Haselwanter, B. and Zaruba, M. M. and Doerler, J. and Rissbacher, C. and Ammenwerth, E. and Bauer, A.},
  title = {Feasibility and effectiveness of a multidimensional post-discharge disease management programme for heart failure patients in clinical practice: the HerzMobil Tirol programme.},
  journal = {Clinical research in cardiology : official journal of the German Cardiac Society},
  year = {2021},
  doi = {https://doi.org/10.1007/s00392-021-01912-0}
}
Semmler, G., Barbieri, F., Thudt, K., Vock, P., Mörtl, D., Mayr, H., Wollmann, C.G., Adukauskaite, A., Pfeifer, B., Senoner, T. and Dichtl, W. Long-Term Technical Performance of the Osypka QT-5, javax.xml.bind.JAXBElement@731a9fda, Ventricular Pacemaker Lead. 2021 Journal of clinical medicine
Vol. 10 
article DOI  
Abstract: Lead-associated complications and technical issues in patients with cardiac implantable electronic devices are common but underreported in the literature. All patients undergoing implantation of the Osypka QT-5 ventricular lead at the University Clinic St. Pölten between 1 January 2006 and 31 December 2012 were retrospectively analyzed ( = 211). Clinical data including pacemaker follow-up examinations and the need for lead revisions were assessed. Kaplan-Meier analysis to estimate the rate of lead dysfunction during long-term follow-up was conducted. Patients were followed for a median of 5.2 years (interquartile range (IQR) 2.0-8.7). R-wave sensing properties at implantation, compared to last follow-up, remained basically unchanged: 9.9 mV (IQR 6.8-13.4) and 9.6 mV (IQR 5.6-12.0), respectively). Ventricular pacing threshold significantly increased between implantation (0.5 V at 0.4 ms; IQR 0.5-0.8) and the first follow-up visit (1.0 V at 0.4 ms; IQR 0.8-1.3; < 0.001) and this increase persisted throughout to the last check-up (0.9 V at 0.4 ms; IQR 0.8-1.2). Impedance significantly declined from 1142 Ω (IQR 955-1285) at implantation to 814 Ω (IQR 701-949; < 0.001) at the first check-up, followed by a further decrease to 450 Ω (IQR 289-652; < 0.001) at the last check-up. Overall, the Osypka QT-5 ventricular lead was replaced in 36 patients (17.1%). This report shows an unexpected high rate of technical issues of the Osypka QT-5 ventricular lead during long-term follow-up.
BibTeX:
@article{Semmler2021,
  author = {Semmler, Georg and Barbieri, Fabian and Thudt, Karin and Vock, Paul and Mörtl, Deddo and Mayr, Harald and Wollmann, Christian Georg and Adukauskaite, Agne and Pfeifer, Bernhard and Senoner, Thomas and Dichtl, Wolfgang},
  title = {Long-Term Technical Performance of the Osypka QT-5, javax.xml.bind.JAXBElement@731a9fda, Ventricular Pacemaker Lead.},
  journal = {Journal of clinical medicine},
  year = {2021},
  volume = {10},
  doi = {https://doi.org/10.3390/jcm10040639}
}
Senoner, T., Pfeifer, B., Barbieri, F., Adukauskaite, A., Dichtl, W., Bauer, A. and Hintringer, F. Identifying the Location of an Accessory Pathway in Pre-Excitation Syndromes Using an Artificial Intelligence-Based Algorithm. 2021 Journal of clinical medicine
Vol. 10 
article DOI  
Abstract: (1) Background: The exact anatomic localization of the accessory pathway (AP) in patients with Wolff-Parkinson-White (WPW) syndrome still relies on an invasive electrophysiologic study, which has its own inherent risks. Determining the AP localization using a 12-lead ECG circumvents this risk but is of limited diagnostic accuracy. We developed and validated an artificial intelligence-based algorithm (location of accessory pathway artificial intelligence (locAP AI)) using a neural network to identify the AP location in WPW syndrome patients based on the delta-wave polarity in the 12-lead ECG. (2) Methods: The study included 357 consecutive WPW syndrome patients who underwent successful catheter ablation at our institution. Delta-wave polarity was assessed by four independent electrophysiologists, unaware of the site of successful catheter ablation. LocAP AI was trained and internally validated in 357 patients to identify the correct AP location among 14 possible locations. The AP location was also determined using three established tree-based, ECG-based algorithms (Arruda, Milstein, and Fitzpatrick), which provide limited resolutions of 10, 5, and 8 AP locations, respectively. (3) Results: LocAP AI identified the correct AP location with an accuracy of 85.7% (95% CI 79.6-90.5, < 0.0001). The algorithms by Arruda, Milstein, and Fitzpatrick yielded a predictive accuracy of 53.2%, 65.6%, and 44.7%, respectively. At comparable resolutions, the locAP AI achieved a predictive accuracy of 95.0%, 94.9%, and 95.6%, respectively ( < 0.001 for differences). (4) Conclusions: Our AI-based algorithm provided excellent accuracy in predicting the correct AP location. Remarkably, this accuracy is achieved at an even higher resolution of possible anatomical locations compared to established tree-based algorithms.
BibTeX:
@article{Senoner2021,
  author = {Senoner, Thomas and Pfeifer, Bernhard and Barbieri, Fabian and Adukauskaite, Agne and Dichtl, Wolfgang and Bauer, Axel and Hintringer, Florian},
  title = {Identifying the Location of an Accessory Pathway in Pre-Excitation Syndromes Using an Artificial Intelligence-Based Algorithm.},
  journal = {Journal of clinical medicine},
  year = {2021},
  volume = {10},
  doi = {https://doi.org/10.3390/jcm10194394}
}
Siller, A., Wachter, G.A., Neururer, S., Pfeifer, B., Astl, M., Borena, W., Kimpel, J., Elmer, S., Spöck, F., Vales, A., Mühlbacher, A., Gaber, M., Willeit, P. and Schennach, H. Prevalence of SARS-CoV-2 antibodies in healthy blood donors from the state of Tyrol, Austria, in summer 2020. 2021 Wiener klinische Wochenschrift  article DOI  
Abstract: Seroepidemiological studies provide important insight into the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV‑2) in our society. We aimed to determine seropositivity of SARS-CoV‑2 antibodies and its cross-sectional correlates in a large cohort of blood donors. In this observational cohort study, we tested healthy blood donors residing in Tyrol, Austria, for SARS-CoV‑2 antibodies using the Abbott SARS-CoV‑2 IgG chemiluminescent microparticle immunoassay. We estimated 95% confidence intervals (95% CI) of seroprevalences using bootstrapping and tested for differences by participant characteristics using logistic regression. Between 8 June and 4 September 2020, we screened 5345 healthy individuals at local blood donor sessions (mean age 42.7 years, SD 13.5 years, 46.7% female). Overall seroprevalence was 3.1% (95% CI 2.7-3.6%, 165 cases), which is 5.1-fold higher (95% CI 4.5-6.0%) than the case number identified by the health authorities in the state-wide testing program (0.6%; 4536 out of 757,634). Seroprevalence was higher in the district Landeck (16.6%, P < 0.001) and in individuals aged < 25 years (4.7%, P = 0.043), but did not differ by gender, blood types, or medication intake. The odds ratio for seropositivity was 2.51 for participants who had travelled to Ischgl (1.49-4.21, P = 0.001), 1.39 who had travelled to other federal states (1.00-1.93, P = 0.052), and 2.41 who had travelled abroad (1.61-3.63, P < 0.001). Compared to participants who had a suspected/confirmed SARS-CoV‑2 infection but were seronegative, seropositive participants more frequently reported loss of smell (odds ratio = 2.49, 1.32-4.68, P = 0.005) and taste (odds ratio = 2.76, 1.54-4.92, P = 0.001). In summer 2020, SARS-CoV‑2 seroprevalence in Tyrolean blood donors was 3.1%. Our study revealed regional variation and associations with young age, travel history and specific symptoms.
BibTeX:
@article{Siller2021,
  author = {Siller, Anita and Wachter, Gregor A. and Neururer, Sabrina and Pfeifer, Bernhard and Astl, Manfred and Borena, Wegene and Kimpel, Janine and Elmer, Sebastian and Spöck, Franziska and Vales, Anja and Mühlbacher, Annelies and Gaber, Manfred and Willeit, Peter and Schennach, Harald},
  title = {Prevalence of SARS-CoV-2 antibodies in healthy blood donors from the state of Tyrol, Austria, in summer 2020.},
  journal = {Wiener klinische Wochenschrift},
  year = {2021},
  doi = {https://doi.org/10.1007/s00508-021-01963-3}
}
Wiesmüller, F., Hayn, D., Kreiner, K., Pfeifer, B., Pölzl, G., Kastner, P. and Schreier, G. Natural Language Processing for Free-Text Classification in Telehealth Services: Differences Between Diabetes and Heart Failure Applications. 2021 Studies in health technology and informatics
Vol. 279, pp. 157-164 
article DOI  
Abstract: Telehealth services for long-term monitoring of chronically ill patients are becoming more and more common, leading to huge amounts of data collected by patients and healthcare professionals each day. While most of these data are structured, some information, especially concerning the communication between the stakeholders, is typically stored as unstructured free-texts. This paper outlines the differences in analyzing free-texts from the heart failure telehealth network HerzMobil as compared to the diabetes telehealth network DiabMemory. A total of 3,739 free-text notes from HerzMobil and 228,109 notes from DiabMemory, both written in German, were analyzed. A pre-existing, regular expression based algorithm developed for heart failure free-texts was adapted to cover also the diabetes scenario. The resulting algorithm was validated with a subset of 200 notes that were annotated by three scientists, achieving an accuracy of 92.62%. When applying the algorithm to heart failure and diabetes texts, we found various similarities but also several differences concerning the content. As a consequence, specific requirements for the algorithm were identified.
BibTeX:
@article{Wiesmueller2021,
  author = {Wiesmüller, Fabian and Hayn, Dieter and Kreiner, Karl and Pfeifer, Bernhard and Pölzl, Gerhard and Kastner, Peter and Schreier, Günter},
  title = {Natural Language Processing for Free-Text Classification in Telehealth Services: Differences Between Diabetes and Heart Failure Applications.},
  journal = {Studies in health technology and informatics},
  year = {2021},
  volume = {279},
  pages = {157--164},
  doi = {https://doi.org/10.3233/SHTI210104}
}
Wurm, A., Zechling, A., Leitner, H., Dammerer, D., Pfeifer, B., Krismer, M. and Liebensteiner, M. Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse 2021 Knee Surgery, Sports Traumatology, Arthroscopy  article DOI  
BibTeX:
@article{Wurm2021a,
  author = {Alexander Wurm and Anna Zechling and Hermann Leitner and Dietmar Dammerer and Bernhard Pfeifer and Martin Krismer and Michael Liebensteiner},
  title = {Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse},
  journal = {Knee Surgery, Sports Traumatology, Arthroscopy},
  publisher = {Springer Science and Business Media LLC},
  year = {2021},
  doi = {https://doi.org/10.1007/s00167-021-06588-7}
}
Zenzmaier, C., Pfeifer, B., Leitner, H. and König-Bachmann, M. Cesarean delivery after non-medically indicated induction of labor: A population-based study using different definitions of expectant management 2021 Acta Obstetricia et Gynecologica Scandinavica
Vol. 100(2), pp. 220-228 
article DOI  
Abstract: Introduction: Most observational studies found that non-medically indicated induction of labor (IOL) is not associated with an increased risk of cesarean delivery compared with expectant management, defined as all births at a later gestation. However, given the higher rate of cesarean delivery at late term, this definition of the expectant management group might bias the results of observational studies in favor of IOL at early or full term when estimating the risk of short-term (eg up to 1 week) expectant management. Material and methods: We conducted a retrospective cohort study including 447 066 singleton term and post-term hospital births that occurred in Austria between 2008 and 2016. Multivariate logistic regression was used to test the association of IOL and cesarean delivery at each week of gestation from 37-41. Expectant management was either defined as all births at “next week or beyond” or “at next week”. Results: Non-medically indicated IOL was associated with increased odds for cesarean delivery at 37 and 38 weeks, and reduced odds at 40 and 41 weeks. At 39 weeks, IOL resulted in comparable cesarean rates compared with expectant management defined as “next week or beyond” (17.2% vs 16.2%; adjusted odds ratio [OR] 0.93; 95% confidence interval [CI] 0.86-1.00; P =.059). However, when defined as births “at the next week”, expectant management was associated with significantly reduced odds for cesarean delivery (13.6%; adjusted OR 0.76; 95% CI 0.70-0.82; P <.001). Comparison of the cesarean delivery rates for the two definitions of expectant management showed that the “next week and beyond” model underestimates the benefit of short-term expectant management by up to 1 week, particularly for IOL at weeks 38 and 39. Conclusions: Our findings demonstrate that the definition of the expectant management group has a significant impact when analyzing the outcome of IOL in retrospective cohort studies. Non-medically indicated IOL is not an all-or-none choice between “elective” induction and indefinite expectant management. Thus, to define the control group as all births at the next week could be useful for clinical decision-making, as it allows to estimate the risks of expectant management until the next appointment compared with immediate IOL.
BibTeX:
@article{Zenzmaier2021,
  author = {Zenzmaier, Christoph and Pfeifer, Bernhard and Leitner, Hermann and König-Bachmann, Martina},
  title = {Cesarean delivery after non-medically indicated induction of labor: A population-based study using different definitions of expectant management},
  journal = {Acta Obstetricia et Gynecologica Scandinavica},
  publisher = {Wiley-Blackwell},
  year = {2021},
  volume = {100},
  number = {2},
  pages = {220--228},
  doi = {https://doi.org/10.1111/aogs.13989}
}
Daleiden, B., Niederstätter, H., Steinlechner, M., Wildt, S., Kaiser, M., Lass-Flörl, C., Posch, W., Fuchs, S., Pfeifer, B., Huber, A. and Oberacher, H. Wastewater surveillance of SARS-CoV-2 in Austria: development, implementation, and operation of the Tyrolean wastewater monitoring program 2022 Waste Water  article DOI  
BibTeX:
@article{Daleiden,
  author = {Beatrice Daleiden and Harald Niederstätter and Martin Steinlechner and Stefan Wildt and Manfred Kaiser and Cornelia Lass-Flörl and Wilfried Posch and Stefan Fuchs and Bernhard Pfeifer and Andreas Huber and Herbert Oberacher},
  title = {Wastewater surveillance of SARS-CoV-2 in Austria: development, implementation, and operation of the Tyrolean wastewater monitoring program},
  journal = {Waste Water},
  year = {2022},
  doi = {https://doi.org/10.2166/wh.2022.218}
}