Outcomes comparison between catheter ablation of ventricular tachycardia in Chagas disease versus ischemic and dilated cardiomyopathy - a retrospective cohort study.

Background: Chagas cardiomyopathy (ChC) is associated with a high burden of ventricular arrhythmias (VA), but long-term outcomes of catheter ablation (CA) in this population remain poorly characterized, especially when compared to other cardiomyopathies. Methods: We performed a single-center retrospective cohort of consecutive patients with structural heart disease undergoing catheter ablation for sustained monomorphic VT (2011-2020) at a tertiary hospital in Brazil, grouped as ChC (n = 164), ischemic cardiomyopathy (ICM; n = 76) or idiopathic dilated cardiomyopathy (DCM; n = 48). The primary endpoint was a composite of all-cause death, heart transplantation, or VT recurrence; time-to-event outcomes were assessed with Kaplan-Meier and multivariable Cox models, and VT recurrence was additionally evaluated using Fine-Gray competing-risk analyses. Findings: We analysed 378 VT ablation procedures in 288 patients (mean age 61 ± 10 years; 208 [72%] male, 80 [28%] female; mean LVEF 35 ± 11%). Compared with ICM and idiopathic DCM, ChC more often required epicardial access (78% versus 15% in ICM and 31% in DCM; p < 0.001) and had lower acute non-inducibility (46% versus 62% in ICM; p < 0.001). Over a median follow-up of 29.0 months (IQR 3.3-69.1), for the last procedure the composite endpoint (death, heart transplant, or VT recurrence) occurred in 71.9% of ChC, 48.6% of ICM, and 58.3% of DCM (overall p = 0.068; pairwise ChC versus ICM p = 0.028). In adjusted Cox models, ChC was associated with higher risk of the composite endpoint (HR 1.73, 95% CI 1.16-2.59; p = 0.008) and higher all-cause mortality (HR 2.41, 1.00-5.78; p = 0.049), but not for VT recurrence, which did not differ by etiology in Kaplan-Meier or competing-risk analyses (Fine-Gray: last procedure p = 0.824; first procedure p = 0.305). Overall mortality was higher in ChC than non-ChC (36.0% versus 21.7%; p = 0.034), driven largely by non-cardiovascular death (p = 0.047) rather than cardiovascular death (p = 0.134). For the composite endpoint, higher LVEF was protective (per 1% increase: HR 0.97, 0.95-0.99; p = 0.017), while major intraprocedural complications conferred the greatest risk (HR 13.70, 3.27-57.39; p < 0.001). Interpretation: Chagas cardiomyopathy was associated with worse adjusted long-term outcomes after VT ablation-driven primarily by higher mortality. Across models, higher LVEF was protective, while markers of clinical instability and major intraprocedural complications identified patients at highest risk. These findings underscore the need for meticulous procedural strategy-particularly when epicardial access is anticipated-and comprehensive post-procedural heart failure and comorbidity management in ChC. Funding: No funding was necessary for this study.