Simultaneous optical and electrical charaterization of cardiac tissue with acute ablation lesions

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Cardiac arrhythmias and subsequent diseases are among the leading causes of death in the Western world and pose an immense burden on public healthcare systems. A standard method to treat various forms of cardiac arrhythmias is radiofrequency ablation obliterating arrhythmogenic tissue in the heart. Up to the present time, the long-term success of catheter ablation is not guaranteed and depends on many factors. Therefore, a second radiofrequency ablation procedure is necessary in many cases. An important key factor for the success of catheter ablation is the reliable creation of a transmural ablation lesion, going through the whole heart muscle, or linear lesions without gaps. Several methods are used to control the ablation procedure, for example temperature monitoring or ultrasound. However, none of these methods can be used to define specific or reproducible endpoints for radiofrequency ablation. It has been shown in an animal study as well as in a prospective clinical study that EGM-based criteria might be used to control radiofrequency ablation procedure and lesion development. A serious disadvantage of these studies was the observational design, so that further studies are required to understand pathophysiologic mechanisms and its impacts on intracardiac electrograms. A major goal of the proposed project is to investigate the electrophysiological characteristics of living cardiac tissue surrounding an acute ablation lesion under defined conditions. It is intended to examine whether complex ablation lesions can be evaluated by intracardiac electrograms or the temporal development of these electrograms. A combination of in-vitro experiments, clinical studies and computer simulations will be performed to solve this research question. The electrical activity of cardiac tissue is measured simultaneously with an already developed in-vitro setup by using fluorescence-optical and electrical techniques. Further enhancements of the existing setup are planned to investigate the extracellular potential of cardiac tissue with complex ablation lesions as well as the propagation of excitation patterns across the tissue. The experimental results from the in-vitro setup will be used to develop further existing computational models of acute ablation lesions. These computer simulations offer the possibility to investigate numerically complex ablation lesions and its influence on the morphologic changes of electrograms. A comparison between the experimental results as well as the clinical data is intended to validate the simulation study. On the basis of this research project, robust and optimized criteria will be identified to assess single point or complex lesions with the help of intracardiac electrograms during the interventional procedure. Furthermore, this study will help to increase significantly the success rate of this clinical treatment.