Non-Invasive Characterization of Electrical Remodeling in a Risk Factor Modification Program

Abstract

Introduction: Weight management in obese subjects is suggested to improve cardiac remodelling. Little is known about the atrial electrical changes that accompany weight reduction.Methods: In a randomized-controlled trial (ANZCTR: 12610000497000), 46 subjects with BMI >27 in sinus rhythm were randomized to a comprehensive risk factor management program or general lifestyle advice, and followed-up for 12-months. Metabolic profiles, pharmacotherapy, BMI, waist circumference (WC) and body surface area (BSA) were recorded. Digital analysis of 12-lead ECGs was used to assess P-wave duration (PWD) and area (PWA) and indexed to BSA (PWD-I and PWA-I), at baseline and at completion of the study.Results: Subjects were well matched for all baseline characteristics (25 active, 21 controls). Mean follow-up was 11.6±1.6 months. Using the paired-sample t-test, significant reduction was seen in all indices at 12-months (PWD; P<0.001, PWA; P=0.001, PWD-I; P=0.014, PWA-I; P=0.016) in the active group. No significant difference was seen in the control group. Using regression analysis with intention-to-treat, active group allocation was predictive of abbreviated P-wave indices (P=0.019). Controlling for age, gender, baseline respiratory disturbance index (RDI), ΔBMI, ΔWC and ΔBSA, significant correlation remained between shortening of PWD-I and number of anti-hypertensive medication used (P=0.026). Conclusion: A structured comprehensive risk factor management program, with aggressive hypertension management and weight reduction, is associated with a favourable improvement in ECG-derived indices of atrial electrical remodelling.