Impact of Catheter Ablation on Atrial Fibrillation Burden and Symptoms in Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: Atrial fibrillation (AF) is more common in patients with hypertrophic cardiomyopathy (HCM) and is often highly symptomatic. The impact of catheter ablation (CA) may be under-reported when evaluated by long-term freedom from any atrial arrhythmia. OBJECTIVES: This study aims to evaluate whether CA of AF in patients with HCM would significantly reduce AF burden and improve symptoms. METHODS: A multicenter registry was established to enroll HCM patients with pre-existing cardiac implantable electronic devices undergoing CA of AF between 2017 and 2021. The first AF recurrence and burden 12 months before and after CA were determined. RESULTS: A total of 81 HCM patients with cardiac implantable electronic devices underwent CA of AF. Patients were followed-up for a minimum of 1-year (35 [Q1-Q3: 23-50] months). AF was paroxysmal in 38 of 81 (46.9%) patients and burden pre-CA was 27.0% (Q1-Q3: 3.0% to 99.0%). A total of 35 (43.2%) patients had AF/atrial tachycardia recurrence within 12 months. AF burden reduced after CA to 0.5% (Q1-Q3 range: 0.0% to 11.1%) (P = 0.001); a 95% CI (13.8% to 100%) relative reduction. European Hearth Rhythm Association class improved by 1.8 ± 1.3 classes (P < 0.001). Of those with AF/atrial tachycardia recurrence, the reduction in AF burden was -33.7% (Q1-Q3: -88.9% to -13.8%) (P < 0.001) and 20 (57.1%) patients reported symptomatic improvement by ≥1 European Hearth Rhythm Association class. AF burden reduction was associated with symptomatic improvement. (r = -0.67; P < 0.001) CONCLUSIONS: AF recurrence is common after CA in HCM patients, but this may under-represent the impact of CA in this cohort. CA significantly reduced AF burden and improved symptoms. A comprehensive evaluation of AF burden, symptoms, and hard endpoints is needed to determine the utility of CA in this context.