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

心律失常和随后的疾病是西方世界的主要死亡原因之一，给公共卫生保健系统带来了巨大的负担。治疗各种形式的心律失常的标准方法是射频消融，消除心脏中的致心律失常组织。到目前为止，导管消融的长期成功尚不能保证，取决于许多因素。因此，在许多情况下，第二次射频消融是必要的。导管消融成功的一个重要关键因素是可靠地创建穿壁消融病变，覆盖整个心肌，或无间隙的线状病变。有几种方法可以用来控制消融过程，例如温度监测或超声波。然而，这些方法都不能用来确定射频消融的特定或可重复的终点。动物研究和前瞻性临床研究表明，基于EGM的标准可以用来控制射频消融过程和病变的发展。这些研究的一个严重缺点是观察性设计，因此需要进一步的研究来了解病理生理机制及其对心内电信号的影响。拟议项目的一个主要目标是研究在特定条件下急性消融损伤周围活的心脏组织的电生理特征。其目的是检查复杂的消融病变是否可以通过心内电信号或这些电信号的时间发展来评估。将采用体外实验、临床研究和计算机模拟相结合的方法来解决这一研究问题。利用已经开发的体外装置，利用荧光-光学和电学技术，同时测量心脏组织的电活动。计划进一步加强现有的设置，以研究复杂消融损伤的心脏组织的细胞外潜力以及兴奋模式在整个组织中的传播。体外实验的结果将被用于进一步发展现有的急性消融损伤的计算模型。这些计算机模拟为研究复杂的数字消融损伤及其对心电图形态变化的影响提供了可能。将实验结果与临床数据进行比较，以验证模拟研究的有效性。在这一研究项目的基础上，将确定稳健和优化的标准，在介入过程中借助心内电信号来评估单点或复杂的病变。此外，本研究将有助于显著提高这一临床治疗的成功率。

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.