BACKGROUND: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) has been associated with greater clinical improvement in women than men. Recently, left bundle branch area pacing (LBBAP) has been shown to be an alternative form of CRT. OBJECTIVES: The purpose of this study was to investigate sex-specific outcomes for death and heart failure events in a large, international, multicenter, cohort of patients undergoing CRT with BVP or LBBAP. METHODS: In this international study of 1,778 patients (575 female and 1203 male), sex-specific survival analysis was performed to compare the effect of LBBAP-CRT relative to BVP-CRT on the combined endpoint of death or heart failure hospitalization (HFH), and secondary endpoints of HFH only, and death alone. RESULTS: Female patients were more likely to have nonischemic cardiomyopathy and left bundle branch block (LBBB) and less likely to have hypertension, diabetes, or coronary artery disease than were male patients. Overall, female patients had a better result with LBBAP compared with BVP than did male patients, with a significant 36% reduction in death or HFH (HR: 0.64; 95% CI: 0.43 to 0.97; P = 0.03) and a significant 60% reduction in HFH alone (HR: 0.4; 95% CI: 0.24 to 0.69, P < 0.01). Women had a greater reduction in death or HFH among those with nonischemic cardiomyopathy (HR: 0.45 95% CI: 0.26 to 0.79; P < 0.01) and LBBB (HR: 0.49; 95% CI: 0.27 to 0.87; P < 0.01). Sex-specific echocardiographic outcomes were better in women than in men. CONCLUSIONS: Women obtained significantly greater reductions in the combined endpoint of death or HFH (primarily driven by reduction in HFH) with LBBAP compared with BVP among patients requiring CRT than did men.

1st Department of Cardiology Interventional Electrocardiology and Hypertension Jagiellonian University Medical College Krakow Poland

Baylor College of Medicine and Texas Heart Institute Houston Texas USA

Cardiocenter University Hospital Kralovske Vinohrady and 3rd Faculty of Medicine Charles University Prague Czech Republic

Department of Cardiology Cardiovascular Research Institute Maastricht Maastricht University Medical Center Maastricht the Netherlands

Department of Cardiology The 1st Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China

Geisinger Heart Institute Wilkes Barre Pennsylvania USA

Hospital Universitari i Politècnic La Fe and Centro de Investigaciones Biomédicas en RED en Enfermedades Cardiovasculares Valencia Spain

Hospital Universitario Virgen de las Nieves Granada Spain

National Heart and Lung Institute Imperial College London London United Kingdom

Rush University Medical Center Chicago Illinois USA

Santa Maria Della Misericordia Hospital Rovigo Italy

University of Ottawa Heart Institute Ottawa Ontario Canada

University of South Florida Morsani College of Medicine Tampa Florida USA

Velammal Medical College Hospital and Research Institute Madurai India

Virginia Commonwealth University Medical Center Richmond Virginia USA