Epidemiology and clinical characteristics of atrial fibrillation in patients with inherited heart diseases

Background
The prevalence and clinical course of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) is well described, though less so for other inherited cardiomyopathies (familial dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction); and inherited arrhythmia syndromes (long QT syndrome, Brugada syndrome or catecholaminergic polymorphic ventricular tachycardia [CPVT]). We examined the frequency, clinical characteristics and AF‐related management and outcomes amongst this patient population.

Methods
We retrospectively studied consecutive probands with inherited cardiomyopathy (n = 962) and inherited arrhythmia syndromes (n = 195) evaluated between 2002 and 2018.

Results
AF was observed in 5% to 31% of patients, with the highest frequency in HCM. Age of AF onset was 45.8 ± 21.9 years in the inherited arrhythmia syndromes compared with 53.3 ± 15.3 years in the inherited cardiomyopathies, with four CPVT patients developing AF at a median age of 20 years. Overall, 11% of patients with AF had a transient ischemic attack or stroke of which a total of 80% were anticoagulated; with 48% of events occurring at a CHA2DS2‐VASc < 2. Amongst sarcomere‐positive HCM, AF was independently associated with age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.02‐1.08; P = .0014), left atrial area (OR, 1.11; 95% CI, 1.05‐1.17; P = .0005) and MYH7 variants (OR, 2.55; 95% CI, 1.16‐5.61; P = .020).

Conclusion
Up to one‐third of inherited heart disease patients will develop AF. While common general population risk factors are key in patients with HCM, the genotype is independently associated with AF. Amongst inherited arrhythmia syndromes, AF is less common, though often occurs below the age of 50 years.