Prognostic implications of left ventricular mechanical dispersion in comparison with QRS duration in heart failure...

QRS duration is a marker of electrical dyssynchrony and predicts left ventricular reverse remodeling among patients with heart failure with reduced ejection fraction (HFrEF). The clinical value of left ventricular dyssynchrony and left ventricular mechanical dispersion (LV-MD) as imaging indicators, however, is less clear. This study aimed to evaluate whether LV-MD offers additional benefit over QRS duration for predicting left ventricular reverse remodeling in patients with HFrEF receiving medical therapy.

In this observational cohort study, 234 patients hospitalized for HFrEF between January 2020 and December 2022 were consecutively included. Speckle-tracking echocardiography was performed to obtain LV-MD, which was calculated as the standard deviation of the time to peak negative longitudinal strain from 17 left ventricular segments. Left ventricular reverse remodeling was determined via baseline and follow-up echocardiography, defined as an increase in left ventricular ejection fraction (LVEF) of ≥10% and a decrease in left ventricular end-diastolic diameter index (LVEDDi) of ≥10% or LVEDDi ≤33 mm/m².

At baseline, the median LVEF was 26%, the QRS duration was 104 ms, and the LV-MD was 72 ms. Although prolonged QRS duration was independently associated with increased LV-MD, 82 (42%) patients with a narrow QRS complex (<120 ms) exhibited an LV-MD >72 ms. During a median follow-up of 19 months, 149 (64%) patients experienced left ventricular reverse remodeling. The proportion of left ventricular reverse remodeling was higher in patients with both LV-MD ≤72 ms and QRS duration <120 ms than in those with a narrow QRS complex alone (84% vs. 66%, P<0.001). LV-MD was a significant predictor of left ventricular reverse remodeling, independent of QRS duration [odds ratio (OR): 0.97; 95% confidence interval (CI): 0.96-0.98; P<0.001]. Moreover, LV-MD demonstrated a greater area under the curve for predicting left ventricular reverse remodeling than did QRS duration (0.78 vs. 0.60; P<0.001).

In HFrEF patients with medical treatment, LV-MD provides additional information on left ventricular dyssynchrony and has superior prognostic value for left ventricular reverse remodeling compared with QRS duration alone.