Left bundle branch vs biventricular pacing for cardiac resynchronization therapy

Abstract Background/Introduction Left bundle branch pacing (LBBP) has emerged as a predominant conduction system pacing technique for reducing QRS duration in patients with intrinsic left bundle branch block (LBBB). It represents a potentially optimal alternative to cardiac resynchronization therapy (CRT) through biventricular pacing (BiVP). Purpose This study aims to compare the efficacy of LBBP-CRT with BiVP-CRT in patients experiencing heart failure with reduced left ventricular ejection fraction. Methods This single-center prospective study involved patients with heart failure and reduced ventricular ejection fraction, encompassing both ischemic and nonischemic cardiomyopathy. LBBP-CRT was employed when BiVP was unsuccessful for any reason, with LBBP-CRT implanted during the same procedure. After 3 and 6 months of preplanned follow-up, comparisons were made between the New York Heart Association (NYHA) functional class and QRS duration in the BiVP-CRT and LBBP-CRT groups. Results Sixty consecutive patients were included in the study (39 males, mean age 64.1 ± 10.6 years, LVEF 29.6% ± 5.6%). All patients completed follow-up, with 32 receiving LBBP-CRT and 28 receiving BiVP-CRT. All 32 LBBP-CRT patients achieved LBB capture, with 14 undergoing selective LBBP and 18 undergoing nonselective LBBP. The LBBP-CRT group exhibited shorter procedure and x-ray exposure times ((11.95 ± 5.77 vs 18.66 ± 10.12). The LBBP lead demonstrated a lower LBB capture threshold at implantation (0.7 ± 0.26 V vs. 1.1 ± 0.40 V; p= 0.039) compared to the CS LV lead in the BiVP-CRT group. Pacing parameters remained stable at the 6-month follow-up (0.72 ± 0.20 V vs. 1.1 ± 0.57 V; p=0.07). During the 3 and 6-month follow-up, pacing parameters remained stable in both groups. Only one patient in the LBBP-CRT group experienced dislodgment of the CS LV lead two days after the procedure, while no patients in the LBBP-CRT group had lead dislodgment. QRS duration significantly shortened in LBBP (171.6 ± 14.3 ms to 131.5 ± 12.5 ms; p=0.047) and remained not significantly shortened in BiVP (174.7 ± 14.1 ms to 150.6 ± 12.9 ms; p=0.06). Both LBBP and BiVP demonstrated improvement in NYHA functional class at the 3 and 6-month follow-up, with statistically significant differences observed between the two groups (change in NYHA functional class from baseline to 6 months -1.2 ± 0.1 vs -0.94 ± 0.11 p=0.047). Throughout the 6-month follow-up, neither the LBBP-CRT nor BiVP-CRT groups experienced rehospitalizations for heart failure, ventricular arrhythmia events, or all-cause death. Conclusions In this series, LBBP-CRT exhibited improvements in NYHA functional class and significantly shortened QRS duration when compared to BiVP-CRT in patients with reduced left ventricular ejection fraction and LBBB.