Abstract 4139663: Impact of Catheter Ablation for Atrial Fibrillation on Clinical Outcomes in Hypertrophic Cardiomyopathy: Findings from the REVEAL-HCM Study

Background: Atrial fibrillation (AF) is the most common arrhythmia associated with hypertrophic cardiomyopathy (HCM), and patients with HCM complicated by AF are known to have a poor prognosis. Although many studies have reported the efficacy of catheter ablation (CA) for AF in various events, a few have shown its efficacy in HCM patients. Moreover, no large-scale, long-term follow-up studies have been conducted. Therefore, we performed a subgroup analysis of the REVEAL-HCM study to evaluate the long-term efficacy of CA for AF in HCM patients. Methods: The REVEAL-HCM study was a retrospective, multicenter, observational longitudinal cohort study that enrolled 3611 consecutive HCM patients aged ≥ 16 years at 23 centers in Japan between January 2006 and December 2018. Of these, patients who either had a medical history of AF or developed AF during the study period were included, excluding those previously treated with CA for AF. Patients were divided into two groups based on whether they received CA post-enrollment. The primary outcome measured was a composite of all-cause death, heart failure hospitalization, and thromboembolism, while the secondary outcomes assessed each of these events individually. Results: Among 1131 HCM patients with AF (67±12 years, 472 females), CA was performed in 284 patients (25%). During a median follow-up of 4.4 years, 455 composite events were observed. Univariate Cox regression analysis showed significantly fewer composite events in the CA group compared to the No-CA group (hazard ratio [HR]: 0.30; 95% confidence interval [CI]: 0.23-0.41; P < 0.001) (Figure). Multivariate Cox regression analysis also demonstrated a significant reduction in composite events (HR: 0.35; 95% CI: 0.25-0.49; P < 0.001). Multivariate Cox regression analysis of the secondary outcomes also revealed significantly fewer events in the CA group for all-cause death (HR: 0.58; 95% CI: 0.34-0.99; P = 0.044), heart failure hospitalization (HR: 0.33; 95% CI: 0.21-0.50; P < 0.001) and thromboembolism (HR: 0.23; 95% CI: 0.10-0.49; P < 0.001). Conclusion: Our study suggests that CA for AF may reduce major clinical events in HCM patients.