Hypertrophic cardiomyopathy and atrial fibrillation: the Cardiomyopathy/Myocarditis Registry of the EURObservational Research Programme of the European Society of Cardiology.

backgroundHypertrophic cardiomyopathy (HCM) is commonly associated with atrial fibrillation (AF), but its impact on outcomes in real-world practice is uncertain. The aim of the study was to evaluate the clinical profile and prognosis of patients with HCM and AF.

methodsOverall, 1739 adult patients with HCM (40.9% women; median age: 55.5 years) were enrolled in the EURObservational Research Programme (EORP) Cardiomyopathy/Myocarditis Registry. Clinical characteristics at baseline and cardiovascular endpoints at 1 year were prospectively assessed.

resultsAt baseline, AF was present in 478 (27.5%) patients; an additional 48 patients (2.8%) developed AF at 1-year follow-up. Oral anticoagulants (OAC) were administered at baseline in 69.5% of the patients. Patients with AF were older and more symptomatic, had higher body mass index, more prevalent cardiovascular risk factors, a history of sustained ventricular tachycardia and implantable cardioverter-defibrillator, lower left ventricular ejection fraction (LVEF), larger left atria (LA) and more advanced LV diastolic dysfunction (pp<0.001 for all). Age at enrolment (OR=1.068, p<0.001), symptom: palpitations (OR=2.191, p<0.001), LVEF (OR=0.978, p<0.001) and LA diameter (OR=1.094, p<0.001) were independent predictors of AF in HCM population. Patients with AF had a higher annual incidence of stroke/transient ischaemic attack (2.6 vs 0.9%, p=0.009) and a trend towards increased all-cause mortality in comparison to the non-AF cohort (3.4 vs 1.7%, p=0.053).

conclusionsAF affects nearly one-third of patients with HCM and is associated with higher symptom burden, increased prevalence of comorbidities, myocardial remodelling and increased annual risk of cerebral ischaemic events. In spite of this, the utilisation of OAC was suboptimal.