A systematic review and meta-analysis of the prevalence, incidence, and predictors of atrial fibrillation in cardiac sarcoidosis

Background: The occurrence of atrial arrhythmias, in particular, atrial fibrillation (AF) in patients with cardiac sarcoidosis (CS) are of growing interest in the field of infiltrative cardiomyopathies. Via a systematic review with meta-analysis, we sought to synthesize data on the prevalence, incidence, and predictors of atrial arrhythmias as well as outcomes in patients with CS. Methods: PubMed/Medline, Web of Science, and Scopus were systematically queried from inception until April 26th, 2023. Using the random-effects model, separate plots were generated for each effect size assessed. Results: From a total of 8 studies comprising 978 patients with CS, the pooled summary estimates for the prevalence of AF was 23% (95% CI: 13%–34%). Paroxysmal AF was the most common subtype of AF (83%; 95% CI: 77%–90%), followed by persistent AF (17%; 95% CI: 10%–23%). In 9 studies involving 545 patients with CS, the pooled incidence of AF was estimated at 5%, 13.1%, and 8.9% at <2 years, 2–4 years, and > 4 years of follow-up respectively, with an overall cumulative incidence of 10.6% (95% CI: 4.9%–17.8%) over a 6-year follow-up period. Increased left atrial size and atrial 18F-fluorodeoxyglucose uptake were identified as strong independent predictors for the development of atrial arrhythmias on qualitative synthesis. Conclusion: The burden of AF and related arrhythmias in CS patients is considerable. This necessitates close follow-up and predictive risk-stratification tools to guide the initiation of appropriate strategies, including therapeutic interventions for prevention of AF-related embolic phenomenon, especially in those with known clinical predictors.