Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases; National Clinical Research Center for Interventional Medicine, China.
Circ Arrhythm Electrophysiol. 2023 Sep;16(9):e011761. doi: 10.1161/CIRCEP.122.011761. Epub 2023 Aug 14.
Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) has shown encouraging results for QRS duration reduction and heart function improvement. However, the feasibility and efficacy of LOT-CRT have not been well established in intraventricular conduction delay patients. This study aims to assess and compare the efficacy and clinical outcome of CRT based on left bundle branch pacing, combined with coronary sinus left ventricular pacing (LOT-CRT) with CRT via biventricular pacing (BiV-CRT) in intraventricular conduction delay patients indicated for CRT.
Consecutive patients with intraventricular conduction delay and CRT indications were assigned nonrandomized to LOT-CRT (n=30) or BiV-CRT (n=55). Addition of the left bundle branch pacing (or coronary venous) lead was at the discretion of the implanting physician guided by suboptimal paced QRS complex and on clinical grounds. Echocardiographic parameters and clinical characteristics were accessed at baseline and during 2-years' follow-up.
Success rate for LOT-CRT and BiV-CRT was 96.8% and 96.4%. LOT-CRT had greater reduction of QRS duration compared with BiV-CRT (42.7±17.4 ms versus 21.9±21.5 ms; <0.001). Higher left ventricular ejection fraction was also achieved in LOT-CRT than BiV-CRT at 6-month (36.7±9.8% versus 30.5±6.4%; <0.05), 12-month (34.8±7.6% versus 30.3±6.2%; <0.05), 18-month (36.3±7.9% versus 28.1±6.6%; <0.005), and 24-month follow-up (37±9.5% versus 30.5±7%; <0.05). Adverse clinical outcomes including heart failure rehospitalization and mortality were lower in LOT-CRT group for 24 months follow-up (hazard ratio, 0.33; =0.035).
LOT-CRT improves ventricular electrical synchrony and may provide greater clinical outcomes as compared with BiV-CRT in intraventricular conduction delay patients. These findings need further evaluation in future randomized controlled trials.
左束支优化心脏再同步治疗（LOT-CRT）在减少 QRS 时限和改善心功能方面显示出令人鼓舞的结果。然而，LOT-CRT 在伴有室内传导延迟的患者中的可行性和疗效尚未得到充分证实。本研究旨在评估和比较基于左束支起搏的 CRT（LOT-CRT）与双心室起搏（BiV-CRT）在有 CRT 适应证的伴有室内传导延迟患者中的疗效和临床结局。
连续入选伴有室内传导延迟且有 CRT 适应证的患者，非随机分配至 LOT-CRT 组（n=30）或 BiV-CRT 组（n=55）。根据非最佳起搏 QRS 复合波和临床情况，由植入医师决定是否加用左束支起搏（或冠状窦）导线。在基线和 2 年随访时评估超声心动图参数和临床特征。
LOT-CRT 和 BiV-CRT 的成功率分别为 96.8%和 96.4%。与 BiV-CRT 相比，LOT-CRT 可更大程度地降低 QRS 时限（42.7±17.4 ms 与 21.9±21.5 ms；<0.001）。LOT-CRT 在 6 个月（36.7±9.8% 与 30.5±6.4%；<0.05）、12 个月（34.8±7.6% 与 30.3±6.2%；<0.05）、18 个月（36.3±7.9% 与 28.1±6.6%；<0.005）和 24 个月随访时（37±9.5% 与 30.5±7%；<0.05）的左心室射血分数也更高。在 24 个月随访期间，LOT-CRT 组的不良临床结局（心力衰竭再住院和死亡率）更低（风险比，0.33；=0.035）。
与 BiV-CRT 相比，LOT-CRT 可改善心室电同步性，并可为伴有室内传导延迟的患者提供更好的临床结局。这些发现需要在未来的随机对照试验中进一步评估。
