Aims: The independent clinical correlates and prognostic impact of QRS prolongation in heart failure (HF) with reduced and preserved ejection fraction (EF) are poorly understood. The rationale for cardiac resynchronization therapy (CRT) in preserved EF is unknown. The aim was to determine the prevalence of, correlates with, and prognostic impact of QRS prolongation in HF with reduced and preserved EF.
Methods and results: We studied 25,171 patients (age 74.6 ± 12.0 years, 39.9% women) in the Swedish Heart Failure Registry. We assessed QRS width and 40 other clinically relevant variables. Correlates with QRS width were assessed with multivariable logistic regression, and the association between QRS width and all-cause mortality with multivariable Cox regression. Pre-specified subgroup analyses by EF were performed. Thirty-one per cent had QRS ≥120 ms. Strong predictors of QRS ≥120 ms were higher age, male gender, dilated cardiomyopathy, longer duration of HF, and lower EF. One-year survival was 77% in QRS ≥120 vs. 82% in QRS <120 ms, and 5-year survival was 42 vs. 51%, respectively (P < 0.001). The adjusted hazard ratio for all-cause mortality was 1.11 (95% confidence interval 1.04-1.18, P = 0.001) for QRS ≥120 vs. <120 ms. There was no interaction between QRS width and EF.
Conclusion: QRS prolongation is associated with other markers of severity in HF but is also an independent risk factor for all-cause mortality. The risk associated with QRS prolongation may be similar regardless of EF. This provides a rationale for trials of CRT in HF with preserved EF.