Moderne Herzschrittmacher sind mit zahlreichen Algorithmen ausgestattet, die sie zu bemerkenswerten therapeutischen und diagnostischen Werkzeugen machen. Die zunehmende Komplexität bringt jedoch unbeabsichtigt neue Herausforderungen mit sich. In dieser Arbeit beschreiben wir eine neue Herzschrittmacher-Induzierte Arrhythmie die oft zum Vorhofflimmern führt.:1. Introduction................................................................................................ 3 1.1. A flashback to the beginning of cardiac pacemakers ............................. 3 1.2. Early pacemakers and significant advances .......................................... 5 1.3. Fast-forward to modern pacemakers ...................................................... 6 1.4. Current challenges .................................................................................. 8 1.5. Identification of a new pacemaker induced arrhythmia .......................... 10 1.6. Methods and results ............................................................................... 11 1.7. Patient characteristics ............................................................................ 13

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Atrial fibrillation is diagnosed in 1-2% of the population, in next decades, it expects a significant increase in the number of patients with this arrhythmia in connection with the aging of the population and the higher incidence of some diseases that are considered as risk factors of atrial fibrillation. The aim of this work is to describe the problem of atrial fibrillation and the methods that allow its detection in the ECG record. In the first part of work there is a theory dealing with cardiac physiology and atrial fibrillation. There is also basic descreption of the detection of atrial fibrillation. In the practical part of work, there is described software for detection of atrial fibrillation, which is provided by BTL company. Furthermore, an atrial fibrillation detector is designed. Several parameters were selected to detect the variation of RR intervals. These are the parameters of the standard deviation, coefficient of skewness and kurtosis, coefficient of variation, root mean square of the successive differences, normalized absolute deviation, normalized absolute difference, median absolute deviation and entropy. Three different classification models were used: support vector machine (SVM), k-nearest neighbor (KNN) and discriminant analysis classification. The SVM classification model achieves the best results. Results of success indicators (sensitivity: 67.1%; specificity: 97.0%; F-measure: 66.8%; accuracy: 92.9%).

The aim of this master thesis is to create a 3D electroanatomical model of a heart atria, which would be able to perform atrial fibrillation. To control the model, the differential equations of the FitzHugh-Nagumo model were chosen. These equations describe the change of voltage on the cell membrane. The equations have established parameters. The modification of them leads to changes in the behavior of the model. The simulations were performed in the COMSOL Multiphysics environment. In the first step, the simulations were performed on 2D models. Simulations of healthy heart, atrial flutter and atrial fibrillation were created. The acquired knowledge served as a basis for the creation of a 3D model on which atrial fibrillation was simulated on the basis of ectopic activity and reentry mechanism. Convincing results were obtained in accordance with the used literature. The advantages of computational modeling are its availability, zero ethical burden and the ability to simulate even rarer arrhythmias. The disadvantage of the procedure is the need to compromise between accuracy and computational complexity of simulations.