Upgrade of right ventricular pacing to cardiac resynchronisation therapy in heart failure: a randomised trial.

BACKGROUND AND AIMS: De novo implanted cardiac resynchronisation therapy with defibrillator (CRT-D) reduces the risk of morbidity and mortality in patients with left bundle branch block, heart failure and reduced ejection fraction (HFrEF). However, among HFrEF patients with right ventricular pacing (RVP), the efficacy of CRT-D upgrade is uncertain.

METHODS: In this multicentre, randomised, controlled trial, 360 symptomatic (New York Heart Association class II-IVa) HFrEF patients with a pacemaker or implantable cardioverter defibrillator (ICD), high RVP burden ≥20%, and a wide, paced QRS complex duration ≥150 ms were randomly assigned to receive CRT-D upgrade (n = 215) or ICD (n = 145) in a 3:2 ratio. The primary outcome was the composite of all-cause mortality, heart failure hospitalisation or <15% reduction of left ventricular end-systolic volume assessed at 12 months. Secondary outcomes included all-cause mortality or heart failure hospitalisation.

RESULTS: Over a median follow-up of 12.4 months, the primary outcome occurred in 58/179 (32.4%) in the CRT-D arm vs. 101/128 (78.9%) in the ICD arm [odds ratio 0.11; 95% confidence interval (CI) 0.06-0.19; p < 0.001]. All-cause mortality or heart failure hospitalization occurred in 22/215 (10%) in the CRT-D arm vs. 46/145 (32%) in the ICD arm (hazard ratio 0.27; 95% CI 0.16-0.47; p < 0.001). The incidence of procedure- or device-related complications was similar between the two arms [CRT-D group 25/211 (12.3%) vs. ICD group 11/142 (7.8%)].

CONCLUSIONS: In pacemaker or ICD patients with significant RVP burden and reduced ejection fraction, upgrade to CRT-D compared to ICD therapy reduced the combined risk of all-cause mortality, heart failure hospitalisation or absence of reverse remodelling.