Comparison of long-term outcomes of patients with heart failure with reduced ejection fraction undergoing cardiac resynchronization therapy with left bundle branch area pacing or biventricular pacing

Cardiac resynchronization therapy (CRT) is a proven treatment for reducing morbidity and mortality in eligible patients with heart failure with reduced ejection fraction (HFrEF). The high non-response rates and lead-related complications of conventional biventricular pacing (BiVP) have increased interest in physiological conduction system pacing methods. Left bundle branch area pacing (LBBaP) has emerged as a prominent alternative. This study aimed to compare the long-term clinical, electrocardiographic, and echocardiographic outcomes of LBBaP versus BiVP in patients undergoing CRT for HFrEF. This retrospective, single-center study included 271 patients with HFrEF (203 BiVP, 68 LBBaP) who underwent CRT implantation between January 2017 and July 2024. Patient demographic data, clinical characteristics, procedural details, complications, and follow-up data were obtained from the hospital's database. The groups were compared in terms of baseline characteristics, post-procedural electrical parameters, 6-month and long-term echocardiographic response, hospitalizations, and all-cause mortality. Kaplan-Meier analysis was used for survival analysis, and Cox regression analysis was employed to identify prognostic factors. The LBBaP group had a significantly narrower post-procedural QRS duration (144±18 ms vs. 153±22 ms; p = 0.005) and a lower X-ray dose (124 vs. 244 Gy; p < 0.001) compared to the BiVP group. At the 6-month follow-up, the LBBaP group showed more significant improvement in NYHA functional class (p=0.006), higher left ventricular ejection fraction (LVEF) (37.7±10.8% vs. 33±10.6%; p=0.005), less moderate-to-severe mitral regurgitation (p=0.005), a lower rate of hospitalization (22.6% vs. 36.7%; p=0.042), and a lower rate of all-cause mortality (2.9% vs. 10.8%; p=0.047). Over a median follow-up of 41 months, there was no statistically significant difference in long-term overall survival between the two groups (p = 0.289). In multivariate Cox regression analysis, baseline eGFR <60 ml/min/1.73 m² (HR: 2.495; p<0.001) and hospitalization within the first 6 months (HR: 1.915; p=0.010) were identified as independent predictors of all-cause mortality, whereas the CRT method (LBBaP vs. BiVP) did not have an independent effect on survival. Our study demonstrates that LBBaP provides superior short-term electrical and echocardiographic improvements compared to BiVP, and is associated with lower rates of hospitalization and mortality within the first 6 months. However, this short-term superiority did not translate into a long-term overall survival advantage. The main determinants of long-term prognosis appear to be patient-related factors, such as baseline renal function and early clinical stability, rather than the CRT pacing modality itself.