Abstract 229: Atrial Fibrillation Effect on the Outcomes and Prognosis of Myocarditis, a Report From the National Inpatient Sample of 2016

Background: Myocarditis of different etiologies can either present with different types of already existing arrhythmias or be the cause of subsequent arrhythmias. Literature have shown that both scenarios hold worse prognosis and outcomes. Methods: We conducted a retrospective cohort study based on the 2016 National Inpatient Sample of adults (>18 years) hospitalized for acute myocarditis of any kind as the primary admitting diagnosis and atrial fibrillation (AF) as a secondary concomitant diagnosis based on ICD-10 codes. All-cause mortality was our primary outcome while length of stay, in-hospital arrhythmia of any kind requiring DCCV, acute respiratory failure, the rate of endotracheal intubation, ICD device insertion and VAD placement during the same hospital stay were our secondary outcomes. We used multivariate regression adjusted for age, sex, race, history of coronary artery disease, history of congestive heart failure, Charlson comorbidity index, hospital region, size and teaching status. STATA-15 was used for statistical analysis. Results: In 2016, there were 8,110 admissions for myocarditis (37.9% females), out of whom 315 (3.9%) had concomitant AF. Mean age was 40y (39.5y without AF, 59y with AF). Our results, table 1, showed that myocarditis with AF significantly increased all-cause mortality (6.3% [20 of 315] vs 1.6% [130 of 7,760], OR 8.28, p Conclusion: Atrial fibrillation appears to be an independent risk factor for higher all-cause mortality rate in myocarditis and is also associated with higher rate of ICD device and VAD implantation during the same hospital stay. Thus, patients with AF who are hospitalized for myocarditis mostly have worse in-hospital outcomes.