Cardiac resynchronization therapy (CRT) reduces morbidity and mortality for patients with heart failure, reduced left ventricular ejection fraction, QRS duration >130 ms and in sinus rhythm.
To identify patient-characteristics that predict the effect, specifically, of CRT-pacemakers (CRT-P) on all-cause mortality or the composite of hospitalisation for heart failure or all-cause mortality.
An individual patient-data meta-analysis of the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) and Cardiac Resynchronization – Heart Failure (CARE-HF) trials. Only patients assigned to CRT-P or control (n = 1738) were included in order to avoid confounding from concomitant defibrillator therapy. The influence of baseline characteristics on treatment effects was investigated.
Median age was 67 (59-73) years, most patients were men (70%), 68% had a QRS duration of 150-199 ms and 80% had left bundle branch block (LBBB). Patients assigned to CRT-P had lower rates for all-cause mortality (HR 0.68 (95% CI 0.56 to 0.81; p < 0.0001) and the composite outcome (HR 0.67 (95% CI 0.58 to 0.78; p < 0.0001). No pre-specified characteristic, including sex, aetiology of ventricular dysfunction, QRS duration (within the studied range) or morphology or PR interval significantly influenced the effect of CRT-P on all-cause mortality or the composite outcome. However, CRT-P had a greater effect on the composite outcome for patients with lower body surface area (BSA) and those prescribed beta-blockers.
CRT-P reduces morbidity and mortality in appropriately selected patients with heart failure. Benefits may be greater in smaller patients and in those receiving beta-blockers. Neither QRS duration nor morphology independently predicted the benefit of CRT-P.

This article is protected by copyright. All rights reserved.