Abstract
BACKGROUND: The prognostic significance of QRS duration (QRSd) in patients with dilated cardiomyopathy (DCM) and a left ventricular ejection fraction (LVEF) between 30% and 50% is unclear, resulting in questions regarding eligibility for cardiac resynchronisation therapy. This study aimed to explore the prognostic role of QRSd in patients with DCM and a LVEF 30-50% or LVEF < 30. METHODS: Patients hospitalised at Fuwai hospital with DCM who had a LVEF ≤ 50% were prospectively included. The primary outcomes were a composite of death, heart transplantation, and rehospitalisation for worsening heart failure. RESULTS: Among the 633 patients included, 302 (47.7%) had a LVEF of 30-50%. The multivariable hazard ratio (HR) for QRSd ≥ 120 ms was 1.65 (95% confidence interval [CI] 1.29-2.11, p < 0.001) for overall DCM patients, 2.8 (95% CI 1.82-4.30, p < 0.001) for patients with LVEF 30-50%, and 1.41 (95% CI 1.02-1.94, p = 0.036) for patients with LVEF < 30%. QRSd ≥ 120 ms tended to be more strongly associated with outcome in patients with LVEF 30-50% than in those with LVEF < 30% despite the non-significant interaction (p = 0.067). DCM patients with QRSd ≥ 120 ms and LVEF 30-50% did not experience a significantly better outcome than those with LVEF < 30% and QRSd < 120 ms after propensity-score matching (HR 0.91, 95% CI 0.61-1.36, p = 0.645). CONCLUSIONS: QRSd independently predicts prognosis in DCM patients irrespective of LVEF and identifies a group of high-risk patients who may benefit from device implantation despite the absence of severely reduced LVEF.