Pediatric Patients Hospitalized with Myocarditis: A Multi-Institutional Analysis

The objective of this study was to identify the patient, institutional, and utilization characteristics associated with outcome in hospitalized pediatric patients with myocarditis. This was a nonconcurrent cohort study of all consecutive pediatric discharges from the 35 academic children's hospitals that are members of the Pediatric Health Information System (PHIS): patients from birth through age 21 years discharged from participating hospitals between January 1, 2005, and December 31, 2005. Patient-level, institution-level, and utilization variables were examined. A total of 427,615 patients were discharged, and 216 (0.05%) were diagnosed with myocarditis. Common etiologies were idiopathic (82%), related to other diseases (6%), and bacterial or viral (3%). Myocarditis patients required considerable support including intravenous immunoglobulin (IVIG; 49.1%), milrinone (45%), epinephrine (35%), mechanical ventilation (25%), extracorporeal membrane oxygenation (7%), and cardiac transplantation (5%). Even in patients with extreme illness scores, IVIG use did not impact survival (P = 0.67). Overall survival of myocarditis patients was 92%. Myocarditis patients who died presented with a higher severity of illness and required frequent use of extracorporeal membrane oxygenation and other ICU therapies. In conclusion, pediatric patients with myocarditis have considerable variability in their presentations and outcomes, use more resources, and die more often than children with other diagnoses. Attempts at using characteristics that uniformly predict illness severity or survival were not successful. Despite increased use in the sickest patients, IVIG conferred no survival advantage.