Randomized Trial of Left Bundle Branch Pacing vs Right Ventricular Pacing in Vulnerable Cardiac Function.

Abstract (English)

BACKGROUND: Right ventricular pacing (RVP) is associated with an increased risk of pacing-induced cardiomyopathy (PICM) in patients with a high pacing burden. Left bundle branch pacing (LBBP), a more physiological pacing modality, may better preserve cardiac function. OBJECTIVES: This randomized trial aimed to evaluate the clinical outcomes of LBBP vs RVP in patients with a high pacing burden with high risk of cardiac dysfunction. METHODS: In this prospective, multicenter, randomized controlled trial, 160 patients with a high pacing burden with high risk of cardiac dysfunction were randomly assigned in a 1:1 ratio to either LBBP or RVP. The primary endpoint was a composite of all-cause mortality, heart failure hospitalization, or PICM. Secondary endpoints were the individual components of the primary endpoints, echocardiographic parameters, and NYHA functional class. RESULTS: During a median follow-up duration of 36 months, the primary endpoint occurred in 9 patients in the LBBP group and in 25 patients in the RVP group (11.6% vs 33.9%; HR: 0.310; 95% CI: 0.145-0.664; P = 0.001), mainly driven by PICM (6.5% vs 18.2%; subdistribution HR: 0.324; 95% CI: 0.119-0.883; P = 0.028). No significant differences were observed in all-cause mortality (P = 0.391) and heart failure hospitalization (P = 0.100) between 2 groups. LBBP showed superior improvements over RVP in left ventricular ejection fraction (mean difference: 5.34; 95% CI: 3.18-7.50; P < 0.001), left ventricular end-diastolic diameter (mean difference: -3.06; 95% CI: -4.38 to -1.73; P < 0.001), and left ventricular end-systolic diameter (mean difference: -3.74; 95% CI: -5.07 to -2.41; P < 0.001) from baseline to 36 months. Patients in the LBBP group also showed favored NYHA functional class compared with those in the RVP group at the 36-month follow-up (1.66 &#xb1; 0.60 vs 1.90 &#xb1; 0.56, P = 0.014). CONCLUSIONS: In patients with a high pacing burden with high risk of cardiac dysfunction, LBBP significantly reduced the risk of the composite outcome, driven primarily by a decreased risk of PICM, and is associated with better echocardiographic improvements and clinical function. (A multicenter, prospective, randomized, controlled trial of left bundle branch pacing and right ventricular pacing in preventing deterioration of cardiac function in patients with ventricular pacing dependence [LBBP-FAVOUR]; ChiCTR2000036553).