Background: The Unmet Need in Cardiac Resynchronization Therapy
Heart failure with reduced ejection fraction (HFrEF) remains a leading cause of cardiovascular morbidity and mortality worldwide. Among patients with HFrEF, those exhibiting left bundle-branch block (LBBB) demonstrate particular electrical dyssynchrony, contributing to ventricular remodeling, reduced cardiac output, and worse clinical outcomes. Cardiac resynchronization therapy (CRT) has become a cornerstone treatment for selected patients with HFrEF and conduction abnormalities, traditionally delivered through biventricular pacing (BiVP). However, despite technological advances, a substantial proportion of patients fail to achieve adequate response to BiVP, highlighting the need for alternative pacing strategies.
Left bundle-branch pacing (LBBP) has emerged as a novel physiological pacing approach that directly captures the left bundle branch system, potentially providing more synchronized ventricular activation than conventional BiVP. Early observational studies suggested favorable outcomes with LBBP, but robust evidence from randomized controlled trials has been limited. The HeartSync-LBBP trial addresses this critical evidence gap by prospectively comparing long-term clinical outcomes between LBBP and BiVP in patients with HFrEF and LBBB.
