Abstract
Lack of defined diagnostic criteria for acute myocarditis makes its diagnosis dependent
on clinical suspicion. The objective of this study was to the current trends in demographics,
clinical manifestations, treatments, and outcomes in the United States for children
hospitalized with acute myocarditis. This retrospective study was conducted using
data collected from the Pediatric Health Information System database for the years
2014 to 2020. We included patients 21 years of age or younger with acute myocarditis.
The statistical analysis was performed using chi-squared test and continuous variables
using Mann–Whitney's U-test for continuous data comparisons. We found 1,199 patients with acute myocarditis.
About 60% of patients required admission to the intensive care unit (ICU). The median
hospital length of stay was 4 days for all patients and 6 days for ICU patients. Two
hundred sixty-five (22.1%) patients required invasive mechanical ventilation, 127
(10.6%) required extracorporeal membrane oxygenation, 33 (2.8%) required ventricular
assist device, and 22 (1.8%) required cardiac transplantations. Milrinone was the
most used vasoactive agent. The overall hospital mortality was 2.3%. Intravenous immunoglobulin
(IVIG) infusion use decreased during the study period. On multivariate analysis, vasoactive
medication use (p < 0.01) and arrhythmia (p = 0.02) were independently associated with increased odds of mortality. IVIG use
(p = 0.01) was associated with decreased odds of mortality. Despite high morbidity and
frequent need for advanced life support measures, the survival outcomes of acute myocarditis
in children are favorable. Vasoactive medication support and occurrence of arrythmia
were independently associated with mortality, most likely due to disease severity.
Administration of IVIG was independently associated with reduced mortality. The Clinical
trial registration is not applicable.
Keywords
myocarditis - children - incidence - outcome
