He Bo, Yu Wenxi, Li Yi, Hu Yingying, Wu Xiaoyan, Zhao Fang, Lessomo Fabrice Yves Ndjana, Yao Shuyuan, Lu Zhibing
Department of Cardiology, Zhongnan Hospital of Wuhan University, 169 Donghu Road, Wuhan, 430071, China.
Cardiovascular Institute, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
J Interv Card Electrophysiol. 2025 May 31. doi: 10.1007/s10840-025-02074-z.
Mitral isthmus (MI) line ablation is associated with a higher success rate of ablation for atrial fibrillation (AF), but completely blocking the MI is often challenging. The purpose of this study was to assess the effectiveness and safety of a systematic, step-by-step approach for completely blocking the MI in patients with AF undergoing MI line ablation for the first time.
A total of 338 consecutive AF patients who underwent MI ablation for the first time were included in the study. MI line ablation was performed in the following sequence: Step 1 involved endocardial linear ablation from the mitral annulus to the left inferior pulmonary vein; Step 2 involved epicardial ablation in the coronary sinus (CS), next to the endocardial ablation line; Step 3 involved epicardial-endocardial insertion site mapping and ablation; Step 4 involved ethanol infusion of the vein of Marshall (EIVOM); and Step 5 involved ablation of the ostium of the VOM, followed by Step 3 if needed. The complete MI block was evaluated using differential pacing maneuvres.
After endocardial linear ablation, 111 patients (32.8%) experienced MI block. Further epicardial ablation in the CS induced MI block in another 89 patients (26.3%). In 42 patients (12.4%), epicardial-endocardial insertion sites were ablated to block the MI. EIVOM was performed in 64 patients (18.9%) to achieve MI block. Ablation at the ostium of the VOM induced MI block in 3 patients, and repeating step 3 induced MI block in 17 patients. The total success rate of MI block was 96.4%. No cardiac tamponade occurred during MI ablation.
With a systematic stepwise approach, acute bidirectional MI block can be achieved with a high success rate and without severe complications.
二尖瓣峡部（MI）线消融与心房颤动（AF）消融成功率较高相关，但完全阻断MI往往具有挑战性。本研究的目的是评估一种系统的、逐步的方法在首次接受MI线消融的AF患者中完全阻断MI的有效性和安全性。
本研究共纳入338例首次接受MI消融的连续性AF患者。MI线消融按以下顺序进行：步骤1包括从二尖瓣环至左下肺静脉的心内膜线性消融；步骤2包括在心内膜消融线旁的冠状窦（CS）进行心外膜消融；步骤3包括心外膜-心内膜插入位点标测和消融；步骤4包括经静脉注射乙醇至Marshall静脉（EIVOM）；步骤5包括消融VOM口，如有需要则重复步骤3。使用鉴别起搏操作评估MI的完全阻断情况。
心内膜线性消融后，111例患者（32.8%）出现MI阻断。在CS中进一步的心外膜消融使另外89例患者（26.3%）出现MI阻断。42例患者（12.4%）的心外膜-心内膜插入位点被消融以阻断MI。64例患者（18.9%）进行了EIVOM以实现MI阻断。VOM口消融使3例患者出现MI阻断，重复步骤3使17例患者出现MI阻断。MI阻断的总成功率为96.4%。MI消融过程中未发生心脏压塞。
采用系统的逐步方法，可高成功率地实现急性双向MI阻断且无严重并发症。
