Linking Activation Patterns with Substrate Based Electrogram Characteristics to Develop Individualized Ablation Strategies for Atrial Fibrillation

房颤是工业化社会中最常见的心律失常，给公共医疗系统带来了巨大的负担。在当前的研究中，深入讨论了潜在的机制和最佳的治疗策略。对于进展状态的患者，考虑了几个概念，主要是消融显示分段心电图的组织和消融旋转激发模式。然而，这两个概念都在辩论中，仍然缺乏将这两种现象联系起来的理论。研究表明，对分离的心电图消融的成功率差异很大，这通常是由于缺少对目标信号的标准化定量描述。因此，所有中心的医生都制定了相当主观的治疗策略，这是很难比较的。转子烧蚀是一个相当新的概念，基本问题还没有得到解答。其中包括转子的稳定性和要消融的组织数量。对转子的时间和空间稳定性进行了深入的讨论，提出了转子是固定在特定解剖区域还是蜿蜒穿过心房的问题。拟议项目的主要目标是将现有的导管消融策略联系起来。特别关注的是心房基质，由于电和结构重构和纤维化，预计它将显示出致心律失常的特性。与新的信号处理技术相结合，可以通过专门的起搏方案识别对心动过速至关重要的区域。将开发计算机算法，该算法可以识别局部尺度上的心脏兴奋模式，也可以在使用全景篮式标测导管测量时识别心脏兴奋模式。对在纤颤过程中观察到的去极化模式(例如转子、波前碰撞等)的统计分析预计将指示病理组织是否倾向于窝藏转子。将在一组患者中进行LGE-磁共振成像的额外测量，以获得有关心房基质(例如纤维化)及其对兴奋动力学和心电图形态的影响的更多信息。诱发心律失常底物特征的确定将允许前瞻性地检测和消融目前没有显示转子但通常有可能维持纤颤过程的区域。通过主要使用电生理实验室已有的设备，我们将确保所获得的结果可以应用于日常临床工作，而不会增加患者的负担，因为需要额外的X光或核磁共振诊断。该项目的结果将有助于了解房颤的潜在机制，并从长远来看提高消融成功率。

Atrial fibrillation is the most common cardiac arrhythmia in industrialized societies and poses immense burdens on public healthcare systems. Underlying mechanisms and best treatment strategies are intensively discussed in current research. Several concepts are considered for patients in a progressed state, mainly the ablation of tissue showing fractionated electrograms and the ablation of rotational excitation patterns. Both concepts, however, are under debate and a theory is still lacking which links both phenomena. Studies have shown strongly varying success rates for the ablation of fractionated electrograms, which is often explained by the missing standardized quantitative description of the targeted signals. Consequently, physicians in all centers develop rather subjective treatment strategies, which are difficult to compare. Rotor ablation is a rather novel concept, and basic questions have not been answered yet. Among those is the stability of rotors and the amount of tissue, which is to be ablated. Both temporal and spatial stability of rotors are intensively discussed, raising the question whether rotors anchor at certain anatomical regions or meander through the atria.Major goal of the proposed project is to link existing strategies of catheter ablation. Special focus is laid on the atrial substrate, which is expected to show proarrhythmogenic properties due to electrical and structural remodeling and fibrosis. Areas which are critical to the tachycardia can be identified by specialized pacing protocols, in combination with novel signal processing techniques. Computer algorithms will be developed, which can identify the cardiac excitation pattern both on the local scale and when measured using panoramic basket type mapping catheters. The statistical analysis of depolarization patterns observed during fibrillation (e.g. rotors, wave-front collisions, ... ) is expected to indicate, whether or not pathological tissue is prone to harboring rotors. Additional measurements with LGE-magnetic resonance imaging will be conducted in a subgroup of patients to obtain extended information about the atrial substrate (e.g. fibrosis) and its impact on excitation dynamics and electrograms morphology. Determination of characteristics of proarrhythmogenic substrate would allow for prospective detection and ablation of areas, which did not currently show rotors, but generally have the potential to maintain the fibrillatory process. By dominantly using equipment which is already available in electrophysiological laboratories, we will ensure that the obtained results can be applied in everyday's clinical work, without increasing the patient burden by additionally required X-ray or MRI diagnostics. The outcome of this project will help to understand the underlying mechanisms of atrial fibrillation and improve success rates of ablations in the long term.