C. J. Luz. Determination and Transformation of Conduction Velocities during a Catheter Study using a Computational Model. Institut für Biomedizinische Technik, Karlsruher Institut für Technologie (KIT). Bachelorarbeit. 2019
Atrial fibrillation (AF) is the most common persistent cardiac arrhythmia. In order to gain a better understanding of cell behaviour, it is necessary to evaluate significant parameters. Studies have shown that local, reduced cardiac conduction velocity (CV) may be responsible for reentry tachycardia. For a local CV determination, a catheter stimulates the atrium locally from three sides and measures the response of the tissue. The available parameters are the time of stimulation and the detected extracellular potential by the catheter. The aim is to determine the anisotropic tissue properties, the direction of propagation and the CV in the area of the catheter. For this purpose, the behavior of the excitation wave was analyzed in computer models by varying the stimulation strength, the conductivity of the tissue and the fiber direction. The results have shown, that the initial stimulation and the shape of the excitation wave have an influence on the determination of CVs. These influences were quantified in order to establish an estimation method that determines the local CV, the anisotropy of the tissue and the direction of propagation. Under the most unfavorable simulated conditions, there is a deviation from the measured CVs to the real CVs of 4% in the propagation direction and of 13 % in the transverse propagation direction. The fibre direction differs by 5◦. These values are obtained without error compensation.