慢径路消融成功靶点的心内电图特征分析

Analysis of intracardiac electrogram at successful target sites for slow pathway ablation

目的 对慢径路消融时成功与不成功靶点的心内电图进行对比分析,以期揭示出成功靶点的心内电图特征。方法 常规电生理检查确诊为典型房室结折返性心动过速(AVNRT)患者87例,应用解剖和心内电图复合定位逐步自后间隔向中间隔方面进行慢径路消融,每一次放电后重复电生理检查直至慢径路消失或心动过速不能诱发为消融终点。分别记录每次放电前A波的时限、幅度、波峰数及相对落后于His束记录部位A波的间期、A/V比和慢径路电位。结果 所有病例均消融成功。平均放电次数(3.2±2.5)(中位数为3)。1例发生Ⅱ度Ⅱ型AVB,2个月后安置DDD永久起搏器。成功靶点与不成功靶点心内电图相比,A波时限较长[(67.5±10.3)ms vs(51.5±9.6)ms,P<0.01]波峰数较多[(2.9±0.8)vs(1.6±0.6),P<0.05]。单从A波时限分析,超过60ms对靶点成功消融的敏感性和特异性分别为86％和84％。慢径路电位在成功靶点发生率高(39％vs17％,P<0.01),对靶点成功消融的敏感性和特异性分别为51％和75％。结论 时限较长、碎裂的A波是消融成功靶点的心内电图特征性表现。慢径路电位在成功靶点发生率高,慢径路电位对靶点部位成功消融敏感性不高,不是靶点定位的必备条件。

Objective To analyse electrogram characteristics of target sites and search for prediction parameters of successful ablation. Methods 87 patients with typical AVNRT were included in this study. Anatomically and electrophysiologically guided mapping and ablation of slow pathway was started posteroseptally in a step-wise manner. Each energy application was followed by assessment of the slow pathway and induction of AVNRT. If unsuccessful, subsequent pulse was applied toward mid-septal area. Intracardiac electrogram at target sites were recorded. Results After a median of 3 pulses (mean 3.2 ± 2.5), AVNRT was rendered non-inducible in all patients. One patient occurred type Ⅱ second degree AVB and two months later DDD artificial pacemaker was im-planted. Successful sites had longer duration [(67.5 ± 10.3) ms vs (51.4±9.6) ms, P<0.01] and more peaks [(2.9±0.8) vs (1.6±0.6),P<0.05] of atrial electro-gram . A local atrial electrogram duration of 60 ms or more was predictive of successful ablation site, with 86% sensitivity and 64% specificity. Slow pathway potentials were more frequently observed at successful (39%) than at unsuccessful (17%) target sites (P<0.01). Slow pathway potentials identified successful ablation with 51% sensitivity and 75% specificity. Conclusion Long, fractionated atrial deflection is the electrogram characteristics of successful ablation site. Slow pathway potential is not a sensitive marker of successful ablation, or a prerequisite for successful slow pathway ablation.