Clinical impact of atrial fibrillation in a nationwide cohort of hypertrophic cardiomyopathy patients

Abstract

BACKGROUND: The clinical implications of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients are incompletely characterized. We investigated the impact of AF on stroke and mortality, assessed the performance of the CHA2DS2-VASc score, and explored the predictors of stroke in HCM patients. METHODS: A nationwide cohort of HCM patients (n=8,349, mean age 60.7) identified from 2010 to 2015 from the Korean National Health Insurance database were followed up for occurrence of ischemic stroke or all-cause death. RESULTS: During a mean follow-up of 2.5 years, the incidence rate of stroke was 2.69 and 5.87, and mortality rate was 2.06 and 4.44 per 100 person-years in non-AF and AF patients, respectively. AF was independently associated with a 60% and 50% increased risk for stroke and all-cause mortality, respectively. The AF-associated increase in risk of stroke was more prominent in HCM patients with no or few risk factors. The CHA2DS2-VASc score showed poor discrimination of stroke risk in HCM patients with AF, mostly due to the high incidence of stroke in patients with scores of 0 or 1. Traditional risk factors were not always associated with stroke in HCM patients with AF; age, heart failure, high blood pressure and GGT were the strongest predictors of stroke in this population. HCM patients without AF also showed increased incidence of stroke at CHA2DS2-VASc ≥1. CONCLUSIONS: AF was independently associated with increased risks for stroke and all-cause mortality in patients with HCM. The CHA2DS2-VASc score showed poor discrimination of stroke risk in HCM patients with AF.