Department of Cardiology, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, No 100, Haining Road, Shanghai, China.
Section of Cardiovascular Diseases, Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
Europace. 2019 Jun 1;21(6):950-960. doi: 10.1093/europace/euy327.
Mitral isthmus (MI) ablation is challenging. We hoped to close those conduction breakthrough sites (CBS) across the MI by elaborate mapping.
After the initial linear ablation, elaborately mapping large areas above and below the MI line and inside the coronary sinus (CS) was sequentially performed to identify the CBS. The shortest distance from the CBS to the MI line was measured. The distant CBS (D-CBS) was identified as those CBS >5.0 mm away from the MI line. We prospectively enrolled 177 consecutive patients. Bidirectional conduction blockage across MI was obtained in 50 (28.2%) patients after the initial linear ablation and was achieved in additional 115 (65.0%) patients following elaborate mapping and reinforcement ablation. After initial linear ablation, 272 CBS (2.14 ± 0.99 CBS/person) were identified, and 226 (83.1%) of them were characterized as D-CBS, including 98 sites (36.0%) >10.0 mm and 39 sites (14.3%) >15.0 mm away. Endocardial and epicardial (CS) reinforcement ablation eliminated 119/272 (43.8%) and 58/272 (21.3%) CBS, respectively. Among the 177 eliminated CBS, 138 D-CBS (78.0%, 11.2 ± 5.6 mm) were confirmed in 95 (74.8%) patients. Moreover, CBS along the course of ligament of Marshall was closed by endocardial ablation more frequently than that along the course of great cardiac vein (52.6%% vs. 35.1%, P = 0.004). Eventually, CS ablation was required only in 64 (38.8%) patients.
Distant CBS, accounted for the majorities of the residual conduction across the MI after initial ablation, could be effectively identified and accurately eliminated by elaborate mapping and ablation around the MI ablation line.
峡部消融具有挑战性。我们希望通过精细的标测来封闭贯穿整个峡部的传导恢复部位（CBS）。
初始线性消融后，依次对峡部上方和下方、冠状窦（CS）内部的大片区域进行精细标测，以识别 CBS。测量 CBS 至峡部线的最短距离。将距离峡部线较远的 CBS（D-CBS）定义为距离峡部线 >5.0mm 的 CBS。我们前瞻性纳入 177 例连续患者。初始线性消融后，50 例（28.2%）患者获得峡部双向传导阻滞，115 例（65.0%）患者在精细标测和强化消融后获得峡部双向传导阻滞。初始线性消融后，共识别出 272 个 CBS（2.14±0.99 个/CBS/人），其中 226 个（83.1%）为 D-CBS，包括 98 个（36.0%）>10.0mm 和 39 个（14.3%）>15.0mm 的 CBS。心内膜和心外膜（CS）强化消融分别消除了 272 个 CBS 中的 119 个（43.8%）和 58 个（21.3%）。在 177 个消除的 CBS 中，95 例（74.8%）患者确认了 138 个 D-CBS（78.0%，11.2±5.6mm）。此外，Marshall 韧带沿线的 CBS 通过心内膜消融封闭的频率高于心大静脉沿线的 CBS（52.6% vs. 35.1%，P=0.004）。最终，仅 64 例（38.8%）患者需要 CS 消融。
初始消融后，贯穿峡部的残余传导以距离峡部线较远的 CBS 为主，通过围绕峡部消融线进行精细标测和消融，可以有效识别并准确消除这些 CBS。
