Context HCM is commonly associated with AF. Current guidelines for AF management omit detailed advice for HCM because of a lack of clinical prediction tools that estimate the risk of developing AF and an absence of adequately powered treatment studies.

Objective To critically review current literature on atrial fibrillation (AF) and thromboembolism in hypertrophic cardiomyopathy (HCM) and meta-analyse prevalence and incidence.

Data Sources PubMed and Web of Science.

Study Selection Studies investigating AF and stroke in HCM as primary or secondary endpoint.

Data Extraction Two investigators independently reviewed and extracted data from the identified articles. A random effect meta-regression model and I² statistics were used for analysis.

Results A population of 7381 patients (33 studies) revealed overall AF prevalence of 22.45% (95% CI 20.13% to 24.77%), I²=78.9% (p<0.001). Overall prevalence of thromboembolism in HCM patients with AF was 27.09% (95% CI 20.94% to 33.25%), I²=61.4% ( p<0.01). Overall AF incidence was 3.08% per 100 patients per year (95% CI 2.63% to 3.54%, I²=86.5%, p<0.001) and incidence of thromboembolism in HCM patients with AF was 3.75% per 100 patients per year (95% CI 2.88% to 4.61%), I²=37.9% (p=0.1). Left atrial (LA) dimension and age were common predictors for AF and thromboembolism. Meta-analysis revealed an LA diameter of 38.03 mm (95% CI 34.62% to 41.44%) in sinus rhythm and 45.37 mm (95% CI 41.64% to 49.04%) in AF. There were no randomised controlled trials of therapy; anticoagulation was associated with lower stroke incidence but data on other interventions were limited and contradictory.

Conclusions AF is common in HCM and associated with high thromboembolic risk. LA dimension and age are independently associated with AF but the literature is insufficient to create robust clinical tools to predict AF or thromboembolism. Most data suggest that AF patients should be anticoagulated.