Prognostic Value of Mid-Range QRS Duration in Patients With Heart Failure With Reduced Ejection Fraction

Prolonged QRS is an established marker of adverse outcomes in patients with heart failure with reduced ejection fraction (HFrEF). However, the prognostic significance of modest QRS prolongation (120-149 ms; mid-range QRS) remains unclear, especially in patients without cardiac implantable electronic devices (CIEDs). This study assessed the natural prognosis associated with mid-range QRS compared with narrow QRS (<120 ms) in a recent Asian cohort of patients with HFrEF.

We analyzed patients with HFrEF from the Epidemiological Multicenter Study for Tailored Treatment in Heart Failure (ELMSTAT-HF; January 2020-October 2023). QRS was measured from 12-lead electrocardiograms. Patients with wide QRS (≥150 ms) or CIEDs were excluded. The primary outcome was a composite of all-cause mortality and heart failure hospitalizations. Multivariable Cox models adjusted for the MAGGIC risk score and log-transformed N-terminal pro B-type natriuretic peptide were used. Among 415 patients, 328 had narrow QRS and 87 had mid-range QRS. Over a median follow-up of 547 days, the primary outcome occurred more frequently in the mid-range QRS group (34.5% vs. 12.5%; P<0.001). Mid-range QRS remained independently associated with adverse outcomes (hazard ratio 3.12; 95% confidence interval 1.91-5.11), consistent across non-left bundle branch block (LBBB) and LBBB subgroups.

Mid-range QRS is an independent predictor of adverse outcomes in HFrEF, even in the absence of LBBB.