Clockwise "Mitral Isthmus Block" complicating ablation of left free wall accessory pathways - two cases and review of the literature.

IF 2.6

Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing Pub Date : 2025-08-23 DOI:10.1007/s10840-025-02119-3

Nikola Kocovic, Koichi Nagashima, Reginald T Ho

{"title":"Clockwise \"Mitral Isthmus Block\" complicating ablation of left free wall accessory pathways - two cases and review of the literature.","authors":"Nikola Kocovic, Koichi Nagashima, Reginald T Ho","doi":"10.1007/s10840-025-02119-3","DOIUrl":null,"url":null,"abstract":"Background: Mitral isthmus block (MIB) complicating radiofrequency ablation (RFA) of orthodromic reciprocating tachycardia (ORT) using left - sided accessory pathways (APs) is poorly understood.Methods: Two cases and a systematic review of the literature of patients (pts) who developed MIB complicating left - sided ORT RFA is presented.Results: Among 27 pts (34 ± 12 years old, 54% female, 68% concealed AP), 15 (56%) had ≥ 1 failed RFA procedure. One RF lesion caused MIB in 6 (22%) (≤ 3 lesions in 11 (41%)). MIB caused switch from eccentric to pseudo-concentric atrial activation (23/27 (85%)) without increasing septal ventriculo-atrial (VAHis) intervals/ ORT cycle lengths (17/18 (94%)). Recurrent ORT with \"concentric\" activation was misdiagnosed as atrio-ventricular nodal reentrant tachycardia (AVNRT) in 3 (11%) - 1 requiring pacemaker implantation after slow pathway (SP) RFA. By targeting earliest retrograde atrial activation on the high mitral annular free wall (1-3 o'clock (17/19 (89%)) above the line of block (LOB), successful AP RFA occurred in 23/23 (100%).Conclusions: Left free wall ORTs with RFA - induced MIB are (1) difficult ablations with > 50% requiring > 1 procedure, (2) can masquerade as AVNRT causing unnecessary SP RFA, and (3) are successfully ablated on the high mitral annular free wall predominantly between 1 and 3 o'clock and always superior to the LOB.","PeriodicalId":520675,"journal":{"name":"Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing","volume":" ","pages":""},"PeriodicalIF":2.6000,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s10840-025-02119-3","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}

引用次数: 0

Abstract

Background: Mitral isthmus block (MIB) complicating radiofrequency ablation (RFA) of orthodromic reciprocating tachycardia (ORT) using left - sided accessory pathways (APs) is poorly understood.

Methods: Two cases and a systematic review of the literature of patients (pts) who developed MIB complicating left - sided ORT RFA is presented.

Results: Among 27 pts (34 ± 12 years old, 54% female, 68% concealed AP), 15 (56%) had ≥ 1 failed RFA procedure. One RF lesion caused MIB in 6 (22%) (≤ 3 lesions in 11 (41%)). MIB caused switch from eccentric to pseudo-concentric atrial activation (23/27 (85%)) without increasing septal ventriculo-atrial (VA_His) intervals/ ORT cycle lengths (17/18 (94%)). Recurrent ORT with "concentric" activation was misdiagnosed as atrio-ventricular nodal reentrant tachycardia (AVNRT) in 3 (11%) - 1 requiring pacemaker implantation after slow pathway (SP) RFA. By targeting earliest retrograde atrial activation on the high mitral annular free wall (1-3 o'clock (17/19 (89%)) above the line of block (LOB), successful AP RFA occurred in 23/23 (100%).

Conclusions: Left free wall ORTs with RFA - induced MIB are (1) difficult ablations with > 50% requiring > 1 procedure, (2) can masquerade as AVNRT causing unnecessary SP RFA, and (3) are successfully ablated on the high mitral annular free wall predominantly between 1 and 3 o'clock and always superior to the LOB.

查看原文本刊更多论文

顺时针“二尖瓣峡道阻滞”合并左侧游离壁副通路消融2例及文献复习。

背景：二尖瓣峡部阻滞（MIB）并发射频消融术（RFA）使用左侧副通路（APs）治疗正交往复式心动过速（ORT）的情况尚不清楚。方法：我们对两例并发左侧ORT RFA的MIB患者进行了系统的文献回顾。结果：27例患者（34±12岁，54%女性，68%隐蔽性AP）中，15例（56%）RFA手术失败≥1次。6例（22%）发生1个射频病变，11例（41%）发生≤3个病变。MIB导致心房活动从偏心转向伪同心（23/27(85%)），而不增加室间隔-心房（VAHis）间隔/ ORT周期长度（17/18(94%)）。有“同心圆”激活的复发性ORT被误诊为房室结性再入性心动过速（AVNRT）， 3例(11%)- 1例需要在慢通路（SP） RFA后植入起搏器。通过靶向阻滞线（LOB）上方高二尖瓣环游离壁(1-3点钟（17/19(89%)）的最早逆行心房激活，成功的AP RFA发生在23/23（100%）。结论：伴有RFA诱导的左游离壁ORTs(1)难以消融，bbbb50 %需要b>手术，(2)可以伪装成AVNRT，造成不必要的SP RFA，(3)在高二尖瓣环状自由壁上成功消融，主要在1至3点钟之间，并且总是优于LOB。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing

自引率

0.00%

发文量