Left bundle cardiac resynchronization therapy versus left bundle optimized cardiac resynchronization therapy

BACKGROUND: In patients undergoing left bundle branch area pacing for cardiac resynchronization therapy (LB-CRT), addition of a coronary sinus lead i.e. Left bundle optimized CRT (LOT-CRT) might confer additional benefit. OBJECTIVES: To compare echocardiographic and clinical characteristics between LB-CRT and LOT-CRT at a 6 month follow up. MATERIALS AND METHODS: This single center randomized controlled trial included patients with non-ischemic cardiomyopathy and left bundle branch block with left ventricular ejection fraction (LVEF) < 35% who underwent implantation of an atrial lead, a left bundle lead and a coronary sinus lead. Patients were randomized to LB-CRT or LOT-CRT 48 h after implant and followed-up for 6 months. LVEF, LV end systolic volume (LVESV), NYHA class, 6-min walk distance (6MWD) and response rates were compared between the two pacing modalities. RESULTS: 26 patients (12 in the LB-CRT group and 14 in the LOT-CRT group) were recruited in the study. The mean QRS duration of the population was 169.8 ± 20.6 ms and the mean LVEF was 21 ± 6.6%. Change in LVEF at 6 months (delta LVEF) in the LB-CRT group (15.7 ± 12.8%) was not significantly different from that in the LOT-CRT group (11.4 ± 14.2%; p = 0.43). Response rate in LB-CRT group (72.7%%), was comparable to that in the LOT-CRT group (71.4%; p = 0.94). LVESV, change in LVESV and 6MWD were also not significantly different between the two modalities. CONCLUSIONS: In patients with non-ischemic cardiomyopathy and LBBB, there was no additional benefit with LOT-CRT compared to LB-CRT.