Effect of catheter ablation vs medical therapy on cardiovascular outcomes in hypertrophic cardiomyopathy with atrial fibrillation

Abstract Background Atrial fibrillation (AF) increases the risks of stroke and mortality. AF ablation in patients with heart failure (HF) was associated with a lower risk of death and hospitalisation for worsening HF. Whether AF ablation is beneficial to improve cardiovascular outcomes in patients with concomitant hypertrophic cardiomyopathy (HCM) and AF remains unclear. Objective To investigate whether AF ablation is more effective than conventional medical therapy for improving outcomes in HCM. Methods 2,281 patients with HCM and AF undergoing catheter ablation or medical therapy (antiarrhythmic drugs or rate control drugs) in 2005–2015 were identified from the Korean National Health Insurance Service database. The primary composite outcome of death from cardiovascular causes, ischaemic stroke, hospitalization for worsening HF, or acute myocardial infarction was compared between catheter ablation and medical therapy using propensity score overlap weighting. The time-at-risk was counted from the first medical therapy, and catheter ablation was analysed as a time-varying exposure. Results Of the included (41.1% female; median age: 66 years), 145 (6.1%) underwent catheter ablation for AF during the study period. During a mean follow-up of 3.1 (IQR 1.3–5.8) years, a total of 831 composite outcomes occurred including 292 cardiovascular deaths and 401 strokes. Catheter ablation, compared with medical therapy, was associated with lower risks of the primary composite outcome (weighted incidence rate: 3.84 vs. 6.43 per 100 person-years; weighted HR 0.61, 95% CI 0.38–0.96) and ischaemic stroke (weighted HR 0.43, 95% CI 0.19–0.97). The association between ablation and a lower risk of composite outcome was more pronounced in cases of ablation success whereas no significant difference was observed in cases of ablation failure. Conclusions In patients with AF and HCM, catheter ablation was associated with a lower risk of adverse cardiovascular outcomes than medical therapy.