Echocardiographic Predictors of Ventricular Arrhythmias Post-Automatic Implantable Cardioverter–Defibrillator Implantation

(1) Background: Ventricular arrhythmias (VAs) are a leading cause of morbidity and mortality in ischemic and non-ischemic heart disease. While automated implantable cardioverter-defibrillators (AICDs) are standard treatment for high-risk patients, predicting future VA post-implantation remains limited. This study evaluated echocardiographic and strain parameters for predicting VA risk in AICD recipients. (2) Methods: This retrospective cohort study included patients who underwent AICD implantation at Westmead Hospital, New South Wales, Australia (January 2014-May 2024). Pre-implant transthoracic echocardiograms (TTEs) were analysed for structural and functional parameters, including left-ventricular (LV) ejection fraction (LVEF), LV global longitudinal strain (GLS), mechanical dispersion (MD), and delta contraction duration (DCD). VA events, defined as appropriate AICD shock or anti-tachycardia pacing, were identified from electronic medical records and device checks. Univariate and multivariate Cox regression analyses were performed. (3) Results: Among 242 patients, 98 experienced VA events. Increased LV end-diastolic diameter, indexed LV mass, and right-ventricular basal diameter were associated with VA events (<i>p</i> < 0.05), whilst LVEF and GLS were not. LV dyssynchrony was greater in affected patients (MD 69.2 ms vs. 63 ms, <i>p</i> = 0.036; DCD 288.8 ms vs. 246.4 ms, <i>p</i> = 0.010). DCD was an independent predictor of VA events (HR 1.003; 95% CI: 1.000-1.006; <i>p</i> = 0.022). (4) Conclusions: DCD may improve risk stratification in AICD patients.