UHF-ECG Outperforms QRS Duration and Morphology in Predicting Responders to Biventricular Cardiac Resynchronization...

Biventricular pacing improves morbidity and mortality in heart failure patients with electrical dyssynchrony. Yet, approximately one-third fail to respond when selection is based on QRS duration and morphology.

This study sought to determine if ultra-high-frequency electrocardiography (UHF-ECG) assesses ventricular dyssynchrony and may better predict cardiac resynchronization therapy (CRT) response.

In this prospective single-center study, 114 patients with heart failure, sinus rhythm, nonright bundle branch block morphology, LVEF ≤35%, and QRS duration >130 milliseconds were enrolled and followed for 6 months. Ventricular electrical dyssynchrony (e-DYS) was derived from UHF-ECG as the interval between earliest and latest activation in any of V₁ to V₇ leads, and its predictive performance was compared with QRS duration, QRS area, negative derivatve action time (NDAT) V₈, and QRS morphology. CRT response was defined as a >15% reduction in left ventricular end-systolic volume.

A total of 73 patients (64%) were responders. Responders more often had nonischemic cardiomyopathy, larger QRS area, longer QRS duration, and greater e-DYS. Optimal cutoffs for CRT response prediction were e-DYS >55 ms, QRS area >81 μVs, NDAT V8 >117 ms, and QRS duration >155 ms. In multivariable analysis, only e-DYS (OR: 1.02 per ms; P = 0.04) and nonischemic cardiomyopathy (OR: 2.8; P = 0.03) independently predicted response. In ischemic cardiomyopathy, e-DYS remained the sole independent predictor. Postimplant Δe-DYS (-37 ms) predicted response more accurately (AUC = 0.73, 95% CI: 0.63-0.83) than ΔQRS area or ΔQRS duration.

UHF-ECG-derived ventricular dyssynchrony predicts response to CRT more accurately than conventional ECG parameters. Both baseline e-DYS and its postimplant reduction identify patients most likely to benefit from biventricular pacing.