立体标测心房碎裂电位及改良步进法消融慢性房颤

The majority of paroxysmal atrial fibrillation (AF) can be cured through catheter ablation currently, but the success rate of ablation of chronic AF is still relatively low. For ablation of chronic AF, most of the electrophysiologists use the "stepwise ablation approach". How to fully identify and completely eliminate the complex fractionated atrial electrogram (CFAE) is the key factor affecting the success rate of ablation AF by using this approach. According to the theory of electrical dissociation between the epicardial layer and the endocardial bundle network in chronic AF, we hypothesized that the active CFAE may appears only in the epicardial layer in some patients and only endocardial mapping is less sufficient to complete elimination of it, and it requires a combination of epicardial and endocardial mapping and ablation. Therefore, based on the most common 3 forms of chronic AF in humans, we will design these 3 animal models of AF through high frequency pacing of atrium, ligation of coronary artery and amputation of partial chordae tendineae. The purpose of this study was to examine the 3-dimensional characteristics of CFAE in each model by simultaneously analyzing CFAE on the epicardial and endocardial surfaces, and design a "modified stepwise ablation approach" to cure chronic AF, and provide a new idea for analysis of the mechanisms of chronic AF. Steps are as follows: isolation of triggering; adjunctive ganglionated plexi ablation to reduce unnecessary passive CFAE ablation and thus avoid excessive ablation; completely elimination of the CFAE showed on the epicardial and endocardial surfaces; linear ablation of the roof and the isthmus of matral annulus.

目前绝大多数阵发性房颤可经导管消融获得治愈。但慢性房颤的消融成功率仍较低，多数电生理学家选用的是"步进法消融策略"。影响该策略成功率的关键因素是，心房碎裂电位（CFAE）的充分识别和消融。依据慢性房颤存在心内膜与心外膜的电学分离理论，我们假设部分CFAE仅出现于心外膜，单纯心内膜标测不足以全面消除主动驱动的CFAE，此时联合心外膜标测，将会提高消融成功率。本项目针对临床上最常见的3种慢性房颤，通过高频起搏心房、结扎冠状动脉及部分离断腱索等技术构建3种犬慢性房颤的动物模型，联合心内膜和心外膜途径，在三维层面立体呈现心房CFAE。同时针对其不同机制，设计改良步进法消融策略：隔离触发灶；附加神经节消融以减少不必要的被动驱动的CFAE消融，避免过度消融；彻底消除三维层面呈现的CFAE；线性消融左心房顶部和二尖瓣环峡部。预期能进一步提高导管消融慢性房颤的成功率；为研究慢性房颤的机制提供一种新的思路。

本研究通过快速心房起搏、结扎冠状动脉、部分剪断键索造成二尖瓣反流三种方式，构建犬心房颤动的模型。之后联合应用肺静脉造影及三维电解剖标测技术对肺静脉口、肺静脉前庭、左心房后壁进行精确定位；之后隔离双侧肺静脉、上腔静脉及冠状静脉窦；隔离GP神经结；联合心内膜和心外膜途径，立体标测消融碎裂电位；线性消融左心房顶部及二尖瓣峡部。通过心房起搏，持续性房颤建模成功率约80%。单纯结扎冠状动脉和或单纯人为造成二尖瓣反流，持续性房颤建模成功率低于15%。双侧肺静脉隔离成功率约45%。Loop Recorder监测术后3个月，通过改良步进法消融持续性房颤，无心房颤动发作仅约占20%。本研究表明，持续性房颤机制复杂。通过改良步进法进行消融，未明确提高持续性房颤术后维持窦律的成功率。