Contemporary outcomes of patients with hypertrophic cardiomyopathy and atrial fibrillation: a nationwide matched cohort study

Background/Introduction Atrial fibrillation (AF) disproportionately affects patients with hypertrophic cardiomyopathy (HCM), contributing to morbidity and mortality. Purpose This study investigated whether HCM patients with AF have worse outcomes than non-HCM patients with AF under contemporary AF management. Methods In this nationwide cohort study using data from 2015 to 2022, patients with HCM and AF undergoing AF catheter ablation were 1:1 propensity score-matched to patients with AF but without HCM undergoing AF catheter ablation. As assessed in a time-to-event analysis, the primary outcome was a composite of all-cause mortality and rehospitalisation for heart failure. Results After matching, 142 patients with HCM hospitalised for AF catheter ablation (median age of 60 years, 28.9% female) were compared to 142 non-HCM patients hospitalised for AF catheter ablation (median age of 60 years, 27.5% female). Over a median follow-up of 34 months, the incidence rate of the primary outcome was higher in the HCM group at 56.2 per 1,000 patient-years, compared to 13.4 per 1,000 patient-years in the non-HCM group (hazard ratio [HR], 4.2; 95% confidence interval [CI], 1.7 to 10.2). The individual incidence rates of all-cause mortality (24.4 vs. 6.6 per 1,000 patient years; HR, 3.6 [95% CI, 1.0 to 13.0]) and rehospitalisation for heart failure (34.2 vs. 6.7 per 1,000 patient years; HR, 5.1 [95% CI, 1.5 to 17.9]) were higher in the HCM group. Conclusion Over a median follow-up of nearly three years, patients with HCM and AF treated with catheter ablation had higher rates of all-cause mortality and rehospitalisation for heart failure compared to non-HCM patients with AF undergoing the same procedure. These findings highlight the substantial and persistent burden of morbidity in HCM patients with AF, even with contemporary treatment strategies.