Abstract
IntroductionSeveral rhythm disturbances have been observed in patients with myocarditis. We aim to determine the prevalence of various arrhythmias and its impact on hospital outcomes in patients with myocarditis.MethodsWe used National Inpatient Sample (NIS) database of the United States for the years 2013 and 2014 to assess the prevalence of arrhythmias in myocarditis and its impact on mortality, length of stay and hospitalization costs. All analyses were performed using STATA 14.2 (College Station,TX).ResultsA total of 10744 myocarditis patients were included in the study. The most common arrhythmias were atrial fibrillation (11.4%), ventricular tachycardia (5.4%), atrial flutter (1.7%), ventricular fibrillation/flutter (0.9%) and supraventricular tachycardia (0.6%). Myocarditis was associated with sudden cardiac arrest in 180 patients (1.6%). Arrhythmias were more common in men (58% vs. 42%, p<0.001) and they were likely to be older (57 years vs. 44, p<0.001). Mortality of myocarditis was high in patients with arrhythmia (7.7% vs. 1%, p<0.001). The risk of mortality associated with myocarditis was high in the presence of arrhythmia in both univariate [Odds ratio (OR)=3.5 (2.4-5.1,p<0.001)] and multivariate analyses [OR=3.4(2.4-4.9,p<0.001)]. However, on subgroup analysis mortality risk was found higher only in male subgroup. Similarly, myocarditis with arrhythmia was associated with longer hospital stay (6.7 days vs. 4.4, p<0.001) and higher total hospital costs.ConclusionArrhythmias are present in nearly 20% of patients with myocarditis. Occurrence of arrhythmias in myocarditis is associated with worse hospital outcome including longer hospital stay, increased hospitalization cost and mortality.