Risk factors for atrial fibrillation in hypertrophic cardiomyopathy.

Atrial fibrillation is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), occurring in approximately 25% of patients, which is four to six times more common than in similarly aged patients of the general population. Atrial fibrillation is poorly tolerated by HCM patients, largely due to their dependence on atrial systole for left ventricular filling. HCM patients who develop atrial fibrillation have an increased rate of heart failure related mortality and disabling or fatal thromboembolic events, as well as functional deterioration due to progressive heart failure when left untreated. Atrial fibrillation is both common in HCM and may lead to significant morbidity and mortality. Accurate risk stratification for atrial fibrillation in this population is crucial as contemporary treatments are highly successful. In this paper, we review the current understanding of known risk factors for atrial fibrillation, including different imaging-based parameters that assess left atrial structural and functional remodeling, electrocardiographic changes that reflect left atrial electrical remodeling, and a focus on comorbid obstructive sleep apnea, and in addition we review variables that have been reported to be predictive of atrial fibrillation. Last, we summarize the accumulating evidence for HCM patients having an intrinsic atrial myopathy.