Cardiovascular Medicine, Toyohashi Heart Center, Aichi, Japan.
Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
JACC Clin Electrophysiol. 2021 Mar;7(3):292-304. doi: 10.1016/j.jacep.2020.09.025. Epub 2021 Jan 27.
This study sought to systematically evaluate the ability of a high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) to rapidly and accurately localize residual endocardial and epicardial conduction after mitral isthmus (MI) ablation, facilitating MI block.
Achieving conduction block across the mitral isthmus (MI) is challenging.
Fifty consecutive patients undergoing MI ablation after pulmonary vein isolation were enrolled. After initial endocardial radiofrequency (RF) ablation across the lateral MI, high-resolution activation mapping of the MI with simultaneous coronary sinus (CS) mapping was performed to verify block or localize residual conduction across the MI during left atrial (LA) appendage and CS pacing. Propagation maps were used to identify residual conduction across the MI as endocardial, via the CS or Marshall tract.
In all 50 patients, after the initial endocardial ablation across the MI, repeat high-resolution mapping of the LA and CS was obtained (median: 3,329 mapped points; 4.0 min of mapping time). The initial endocardial MI ablation resulted in block in 9 of 50 patients (18%). In the remaining 41 patients, the propagation map identified residual conduction in 4 patterns: 1) only endocardial gap in 12 patients (29%); 2) only CS connection in 10 patients (24%); 3) both endocardial and CS connections in 14 patients (34%); and 4) Marshall tract connection in 5 patients (12%). In 8 patients, the propagation map revealed residual conduction, despite differential atrial pacing suggesting bidirectional block. Focal ablation at the identified residual conduction site (median: 0.7 min of RF) resulted in block in 49 of 50 (98%) patients.
High-resolution propagation maps of the LA/CS rapidly and accurately localize residual endocardial and epicardial conduction across the MI. Focal ablation with short RF time at the identified gap(s) achieved complete block across MI in 98% of cases.
本研究旨在系统评估高分辨率标测系统（波士顿科学公司的 Rhythmia）快速准确地定位二尖瓣峡部（MI）消融后残余心内膜和心外膜传导的能力，以促进 MI 阻滞。
实现 MI 的传导阻滞具有挑战性。
连续纳入 50 例接受肺静脉隔离后 MI 消融的患者。在初始心内膜射频（RF）消融外侧 MI 后，对 MI 进行高分辨率激活标测，并同时进行冠状窦（CS）标测，以验证 MI 阻滞或定位左心房（LA）心耳部和 CS 起搏时 MI 内的残余传导。传播图用于识别 MI 内的残余传导，包括心内膜、CS 或 Marshall 束途径。
在所有 50 例患者中，在 MI 初始心内膜消融后，均获得了 LA 和 CS 的重复高分辨率标测（中位数：3329 个标测点；标测时间 4.0 分钟）。初始心内膜 MI 消融导致 9 例（18%）患者阻滞。在其余 41 例患者中，传播图识别出 4 种残余传导模式：1）仅心内膜间隙 12 例（29%）；2）仅 CS 连接 10 例（24%）；3）心内膜和 CS 连接均有 14 例（34%）；4）Marshall 束连接 5 例（12%）。在 8 例患者中，尽管差异心房起搏提示双向阻滞，但传播图显示仍存在残余传导。在确定的残余传导部位进行局部消融（中位数：0.7 分钟 RF）后，50 例中的 49 例（98%）患者实现了阻滞。
LA/CS 的高分辨率传播图可快速准确地定位 MI 内的残余心内膜和心外膜传导。在确定的间隙处进行短时间 RF 局部消融可使 98%的病例 MI 完全阻滞。
