The Left Bundle Cardiac Resynchronization Therapy Trial

Cardiac resynchronization therapy (CRT) via biventricular (BiV) pacing significantly reduces morbidity and mortality in patients with left bundle branch block (LBBB), impaired LV function and heart failure in spite of optimal medical treatment. CRT positive effects are based on the existence of an electromechanical dyssynchrony induced by the abnormal activation sequence associated with the presence of a left bundle branch block (LBBB), which is thought to be responsible for a negative LV remodeling leading to LVEF impairment and heart failure progression. However, one third of patients undergoing CRT are considered non responders due to different reasons. Recently, left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing modality aiming for conduction system recruitment in patients with normal or impaired atrioventricular conduction, including patients with LBBB. LBBAP achieves LBBB correction in up to 85% of the cases and thus could be a promising pacing modality for CRT candidates.