Comparison of clinical outcomes of left bundle branch pacing versus biventricular pacing in patients candidate for resynchronization therapy
D Martinez, M Simoes, T Santos, R Ventura, I Cruz, M Primo, J Ferreira, E Jorge, L GoncalvesAbstract
Background/Introduction
Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is a well-established therapy in patients with heart failure with reduced left ventricular ejection fraction (HFrEF). Recently, conduction system pacing (CSP) using left bundle branch pacing (LBBP) has emerged as an alternative to BVP in patients requiring CRT. However, there is a lack of comparative data between modalities in patients with HFrEF.
Purpose
To compare the clinical outcomes between BVP and LBBP among patients undergoing CRT.
Methods
This prospective single-center observational registry included consecutive patients with HFrEF (left ventricular ejection fraction [LVEF] < 50%) undergoing CRT implantation from January 2023 to January 2025. The primary outcome was echocardiographic response to CRT during follow-up. Response was defined as LVEF improvement of more than 5% and super-response was defined as improvement in LVEF more than 15%. Secondary outcome was death and emergency room (ER) visit for acute heart failure (AHF). Multivariable Cox proportional hazards models estimated risks for ER visit due to AHF and Kaplan Meier estimates of cumulative survival free from emergency department visit due to AHF.
Results
A total of 176 patients were analyzed: 88 treated with CSP and 88 with BVP. There was no difference in age and gender between groups. Median follow-up was 835 days (IQR 629; 967). There was no significant difference in baseline QRS between CSP and BVP (167±26 vs 161±26 ms; p=0.276), baseline LVEF (30±9% vs 32±8%, respectively; p=0.236) and ischemic cardiomyopathy (38% vs 40%, respectively; p=0.801). Paced QRS duration was significantly narrower than baseline in CSP (122±16 vs 167±26 ms; p<0.001) and BVP (148±28 vs 161±25 ms; p=0.001) and significantly narrower in CSP compared to BVP (122±15 vs 147±27 ms; p<0.001). Echocardiographic response was more frequent in CSP (90% vs 61%; p=0.005), as well as super-response to CRT (40% vs 20%; p=0.05). LVEF improved more in CSP (15±10% vs 8±12%; p=0.002). ER visit for AHF was less frequent in CSP (2% vs 11%; p=0.017). There was no difference in death between groups (p=0.552). CSP was predictor of reduced ER visit for AHF (adjusted HR 0.198, 95% CI 0.042-0.927; p=0.04). Kaplan–Meier shows patients treated with CSP demonstrated higher event-free survival from ED attendance due to AHF (fewer events) compared to those treated with BVP, with a significant difference observed in the log-rank test (Figure 1).
Conclusion(s)
In this cohort of patients, CRT with CSP provided improved clinical outcomes when compared to CRT with BVP, and may be a reasonable alternative to BVPKaplan-MeyerFor image description, please refer to the figure legend and surrounding text.