Non-invasive assessment of ventricular electrical uncoupling by electrocardiographic imaging as a predictor of biventricular pacing cardiac resynchronization therapy response

Background Biventricular pacing (BiVP) remains the standard approach for cardiac resynchronization therapy (CRT). However, approximately one-third of patients do not respond to CRT, and reliable electrocardiographic imaging (ECGI) predictors of response are still lacking. ECGI provides a detailed, non-invasive assessment of ventricular activation and may offer valuable insights into the mechanisms underlying CRT response. Purpose To identify whether ECGI-derived metrics and clinical variables measured at baseline, after implantation, and their changes can predict response to BiVP-based CRT. Methods Thirty-three patients with heart failure undergoing BiVP for guideline-based CRT indication were included from two centres. Baseline clinical, echocardiographic, electrocardiographic and ECGI data were collected. ECGI metrics assessed included Total Activation Time (TAT), 95th percentile of Left Ventricular Activation Time (LVAT95), Left Ventricular Dyssynchrony Index (LVDI), and Ventricular Electrical Uncoupling (VEU). CRT response was defined as an improvement in left ventricular ejection fraction (LVEF) >5 points without death or heart transplantation at 6 months. Multivariate logistic regression analyses were performed to identify independent predictors of CRT response. Results Twenty-four patients (73%) were responders. The percentage of ventricular pacing was similar between groups (97% (±3) in responders vs. 94% (±3) in non-responders). In univariate analysis, only final VEU and ΔVEU (basal VEU minus post-implant VEU) were significantly associated with CRT response. In multivariate analysis, ΔVEU remained the only independent predictor (OR 1.08, 95% CI 1.02–1.16, p = 0.014). ROC analysis confirmed that a ΔVEU threshold of 18ms differentiated responders from non-responders (sensitivity 0.67, specificity 0.88, PPV 0.67, NPV 0.88). Conclusion In patients undergoing BiVP, ECGI enables detailed, non-invasive characterization of ventricular electrical synchrony. ΔVEU was the only independent predictor of response. These findings suggest that ECGI could serve as a valuable tool for post-implant evaluation and optimization of cardiac resynchronization therapy.