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

BACKGROUND

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.

OBJECTIVES

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

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.