Subahi A, et al. – In this analysis, investigators focused on the impact of atrial fibrillation (AF) on the in-hospital outcomes of patients with acute myocarditis. Using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes, eligible patients (aged ≥ 18 years) with a primary diagnosis of acute myocarditis in the National Inpatient Sample (from 2007 to 2014) were identified and enrolled. Experts found that these patients experienced higher in-hospital mortality vs those without AF. Findings suggested an association of AF with a higher risk of cardiogenic shock, cardiac tamponade, and acute kidney injury. The results suggested that patients with AF were more likely to have non-routine hospital discharge, longer length of stay, and higher cost of hospitalization.