不同心房颤动模型心房电图的机制探讨

The machnisms of atrial fibrillation (AF) are not clearly established, which may include many factors in the genesis and perpetuation of atrial fibrillation,such as driving source, electrical remodeling, anatomy remodeling， inflammation and so on. The study aims to elucidate the formation principles of the atrial electrogram during atrial fibrillation by means of making four canine models of AF,investigating types of atrial electrogram, and correlating them with AF in different canine models. Four canine models of AF reflect the different pathologic process of the above mentioned four aspects of AF repectively. Methylcholine model corresponds with driving source in AF, mitral regurgitation model corresponds with inflammation, pacing model corresponds with electrical remodeling, and the model of congestive heart failure (CHF) corresponds with anatomy remodeling. Furthermore, the atrial electrograms are divided into 4 types according to their characteristics and investigated with the methods of time and frequency domain analysis of atrial electrogram of AF . Combined with analysis of the results of cryoablation of pulmonary veins and histologic examination, we are trying to vertfy the following hypothesis: 1. the slower atrial electrogram is the forced electrogram that is driven by the drivers of atrial fibrillation. 2. Complex fractionated atrial electrograms (CFAEs) may have different mechanisms in different models. During AF corresonding driving source, the CFAEs are due to the electrical conduction block near the rotors and during AF corresponding anatomy remodeling, the CFAEs are caused by the fibroblasts intermixed with normal myocardium and nervous fibers . 3. Rotor-like electrograms are due to the driver of AF with triggers. The rotors are caused by complex histologic tissue containing neuronal cell in driving AF and caused by electrical remodeling in AF induced with pacing. Because electrical fibrillatory conduction of the atrium is an essential aspect of atrial fibrillation (AF), it is necessary to investigate characteristics of atrial electrogram and to elucidate its formation principle for understanding the mechanisms of the atrial fibrillation and guiding ablation of the AF。

心房颤动(房颤)的机制仍无定论，目前认为包括触发灶,心房电重构,解剖重构、炎症和神经体液等多个方面。本项目拟建立各种不同机制的犬房颤模型,在对心房电图进行细致分类的基础上,通过对心房电图的时域和频域分析, 阐明心房电图与不同房颤模型之间的关系,同时结合观察对特定部位的消融结果和组织学特征,探讨各种心房电图产生的原理是否符合以下假设: 1.频率较慢的心房电图是被动驱动性电激动；2.碎裂电位在触发性房颤中是驱动房颤激动点周围激动，在持续性房颤则是房颤维持的机制,后者产生的组织学基础是纤维细胞的增生；3.转子样电图在触发性房颤是驱动灶电位,其组织学本质具有间质,心肌,神经纤维参杂存在的特征；持续性房颤与肺静脉触发的房颤相比,转子样电图则分布于心房各部位,其本质是电重构导致的微折返。房颤的电学本质是心房颤动样电激动，通过研究房颤时心房局部电激动的特征和形成原理，有助于认识房颤的机制和指导消融治疗。