Prognostic impact of atrial fibrillation in hypertrophic cardiomyopathy: a systematic review

Background Atrial fibrillation (AF) is an important arrhythmia in hypertrophic cardiomyopathy (HCM). Objectives To conduct a systematic review of published literature to: (a) assess the incidence of AF in HCM and (b) examine the impact of AF on risk of thromboembolism, heart failure, sudden death and mortality in HCM. Methods Search of all major databases (Pubmed, MEDLINE, Embase, Cochrane, Scopus, Web of Science) was performed to April 2020 using the search terms "atrial fibrillation" AND/OR "hypertrophic cardiomyopathy" in the title or abstract. 51 of the 1,565 citations met the inclusion criteria. Results Using random-effects modelling, the estimated pooled prevalence of AF amongst 21,887 HCM patients (36 studies) was 22.3% (95%, 19.9-24.8) and the pooled incidence of AF was 2.5 cases per person-years (95% CI 1.9-3.0). 15,444 patients from 28 studies were included in analysis of outcome data (mean age was 49.9 years; 32.7% female; mean LVEF 69%). Over a median follow up duration of 6.9 years (range 2.8-11.7 years), AF, compared to sinus rhythm (SR), was associated with significantly increased risk of thromboembolism [relative risk (RR) 7.0; 95% CI 4.6-10.7; I-2 = 57%], heart failure (RR 2.8; 95% CI 1.6-4.6; I-2 = 82%), sudden death (RR 1.7; 95% CI 1.3-2.3; I-2 = 0%), and all-cause mortality (RR 2.5; 95% CI 1.8-3.4; I-2 = 69%). Conclusions AF is highly prevalent in patients with HCM. The presence of AF is associated with major adverse clinical outcomes. These findings suggest that both, aggressive screening and treatment of AF, are likely to have major prognostic impact on outcomes in HCM.