ENHANCING VENTRICULAR TACHYCARDIA ABLATION OUTCOMES: THE IMPACT OF FUNCTIONAL MAPPING IN CHAGAS CARDIOMYOPATHY
Authors: Wilnes Bruno , Castello-Branco Beatriz , de Araújo Silva Gustavo , Mayrink Marina Pereira , da Silva José Luiz Padilha , Barbosa Marco Paulo Tomaz , França Anna Terra , França Marcos Roberto Queiroz , de Araújo Crizianne Rodrigues Santos , de Miranda Reynaldo Castro , Ribeiro Antonio Luiz Pinho , do Carmo Pereira Nunes Maria , do Carmo André Assis Lopes 
Published: February 2024

Background: Chagas cardiomyopathy presents a significant public health challenge in Latin America, marked by high rates of ventricular tachycardia (VT) and implantable cardioverter-defibrillator (ICD) interventions. This study explores the efficacy of functional mapping strategies in VT ablation for Chagas cardiomyopathy compared to conventional voltage map-based approaches. Methods: This observational study, involving 66 patients, employed electroanatomic mapping for both epicardial and endocardial regions. In voltage-based mapping (group 1), all patients underwent bipolar substrate mapping with standard scar settings for epicardial and endocardial regions, while functional mapping (group 2) was obtained using a single ventricular extra-stimulus with Late Potential and Isochronal Late Activation Maps associated with annotation of decremental and blocked electrograms. The primary endpoint was post-ablation VT recurrence over a 30-month follow-up. Results: Voltage-based and functional mapping groups presented 42 and 24 patients, respectively. When compared to the voltage-based mapping strategy, functional mapping-assisted procedures were associated with lower post-ablation VT recurrence on Kaplan-Meier’s log-rank test (P=0.045). After multivariate analysis, functional mapping independently associated with a 90.3% reduction in the risk of 30-month VT recurrence (HR: 0.097, 95% CI: 0.012-0.760, P=0.026) compared to voltage-based mapping. Conclusion: Functional mapping in Chagas cardiomyopathy VT ablation is associated with significantly reduced recurrence rates, emphasizing its potential as an effective strategy in this challenging condition. This study provides valuable insights for improving VT ablation outcomes. However, there is a dire need for a large-scale randomized controlled trial to generate high-quality evidence in this field.

What Is Known

1) Functional mapping holds the potential advantage of identifying substrate situated within normal voltage areas, but there is no direct comparison between functional mapping and conventional voltage map-based strategy.

2) Chagas cardiomyopathy, a highly arrhythmogenic disease, is linked to higher rates of post-ablation ventricular tachycardia (VT) recurrences and poor overall prognosis.

What The Study Adds

1) After adjusting for confounding predictors, a functional map-based strategy showed a 90.3% reduction in post-ablation VT recurrence over a 30-month follow-up period.

2) In 26.8% of patients with Chagas cardiomyopathy referred for VT ablation, a periaortic substrate was identified—a location not previously documented in this condition; poor mapping of this region may contribute to ablation failure.

Graphical Abstract