Two-year outcomes of left bundle branch area pacing versus traditional right ventricular pacing in middle-aged adults: A registry-based trial

Aims Prolonged right ventricular pacing (RVP) increases the risk of cardiomyopathy, atrial fibrillation, heart failure (HF), and mortality. This registry-based trial compared left bundle branch area pacing (LBBAP) with RVP in patients younger than 65 years. Methods and results Using the ConTempoRary Cardiac Stimulation in Clinical practicE: lEft, BivEntriculAr, Right, and conDuction System Pacing (TREEBEARD) registry (NCT06324682), patients were randomized 1:1 to LBBAP or RVP. The primary endpoint was a composite of cardiovascular (CV) death and HF hospitalization (HFH); secondary endpoints included individual components and all-cause mortality. A total of 344 patients (mean age 58.5 years, 215 males, 172 per arm) were included. At 2 years, the primary composite endpoint occurred in 6.3% of LBBAP vs. 12.7% of RVP patients (HR, 0.78; 95% CI, 0.59-0.87), representing a 22% risk reduction. Subgroup analyses aligned with primary findings. Left bundle branch area pacing significantly reduced HFH risk (HR, 0.79; 95% CI, 0.63-0.86) but showed no difference in CV mortality (HR, 1.02; 95% CI, 0.79-1.32) or all-cause mortality (HR, 1.00; 95% CI, 0.72-1.38). Conclusion Left bundle branch area pacing significantly lowered the 2-year composite of CV death and HFH compared to RVP in patients aged <65 years old. However, it did not reduce CV or all-cause mortality individually compared to RVP. Clinical Trial Registration TREEBEARD (NCT06324682)