Understanding LOT-CRT: Current Insights, Limitations, and Our Center's Experience

Cardiac resynchronization therapy (CRT) using biventricular (BiV) pacing is the standard treatment for heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) and electrical dyssynchrony. However, one in three patients remains a non-responder. Left bundle branch area pacing (LBBAP) could represent a more physiological alternative, but its effectiveness is limited in cases of atypical left bundle branch block (LBBB) or intraventricular conduction delay (IVCD). Left Bundle Branch Pacing Optimized cardiac resynchronization therapy (LOT-CRT) integrates LBBAP with coronary sinus (CS) lead pacing to improve electrical synchrony and clinical outcomes. This review evaluates the feasibility, advantages, disadvantages, and clinical outcomes of LOT-CRT. Additionally, we describe our center's experience and propose an evidence-based implantation algorithm. A review of published studies investigating LOT-CRT was conducted, comparing its effectiveness with BiV-CRT and LBBAP alone using QRS narrowing, LVEF improvement, left ventricular remodeling, New York Heart Association (NYHA) class changes and NT-proBNP levels. It was found that LOT-CRT outperforms BiV-CRT or LBBAP alone in selected populations, at the cost of higher clinical skills, longer procedural times, and specific device setups. Randomized trials are underway to further define its role in clinical practice.