Impact of Catheter Ablation on Ventricular Tachycardia Recurrence in Patients with Chagas Cardiomyopathy Following implantable cardioverter-defibrillator Implantation: A Competing Risks Analysis

ABSTRACT Background Chagas cardiomyopathy (ChC) is a highly arrhythmogenic condition with frequent implantable cardioverter-defibrillator (ICD) therapies and poor clinical outcomes. While catheter ablation is a promising strategy for ventricular tachycardia (VT) management, its effectiveness versus medical therapy in this population remains unclear. This study aimed to evaluate the impact of VT ablation versus medical treatment on VT recurrence and all-cause mortality in patients with ChC and ICDs for secondary prevention, and to compare outcomes between functional and conventional ablation strategies. Methods In this prospective cohort study, 127 patients with ChC and ICDs were followed for up to two years. Patients were divided into groups according to the treatment received: catheter ablation (n=67) or medical therapy (n=60). The primary outcome was VT recurrence, analyzed with death as a competing risk. Multivariable competing risk and Cox regression models were used. Results During follow-up, 69 patients had VT recurrence and 40 died. At 24 months, arrhythmia-free survival was 76.2% in the functional ablation group, versus 34.7% and 32.3% in the conventional ablation and medical groups, respectively. Functional ablation was associated with lower risk of VT recurrence (HR: 0.332; 95% CI: 0.121–0.901; p=0.047), and remained protective after adjustment (HR: 0.236; 95% CI: 0.079–0.709; p=0.010). VT recurrence within 30 days post-ablation predicted higher mortality (adjusted HR: 3.247; 95% CI: 1.216–8.665). Conclusions Catheter ablation, particularly with functional mapping, significantly reduced VT recurrence in ChC patients with ICDs. Early VT recurrence post-ablation independently predicted mortality, underscoring its prognostic importance. Clinical Perspective What Is Known Patients with Chagas cardiomyopathy experience a high burden of ventricular tachycardia (VT) and frequently require implantable cardioverter-defibrillators (ICDs) for secondary prevention. Catheter ablation is a recognized strategy to reduce VT burden in structural heart disease, but its efficacy in Chagas cardiomyopathy has not been clearly established. What The Study Adds Adjusted comparisons demonstrated improved survival free of VT recurrence in patients undergoing catheter ablation, with the functional mapping strategy performing better than voltage-based ablation and medical therapy. VT recurrence within 30 days post-ablation was independently associated with increased mortality, highlighting its value as a prognostic marker. These findings support early referral and the use of functional ablation strategies in this high-risk population to improve arrhythmia control and clinical outcomes.