Myocarditis in Paediatric Patients: Age and Gender Are Influencing Incidence, Severity, and Clinical Course: Initial Data Analysis from the German Multi-Centre Registry (“MYKKE”)

Objective: There is only sparse evidence regarding the epidemiology, diagnosis and therapy of myocarditis in children and adolescents. Immunological differences between children and adults may cause age-related differences in the presentation, course and might explain a higher proportion of with severe heart failure in pediatric patients. The aim of this study is to provide data on age-related clinical features of myocarditis.

Methods: After an initial 6-month pilot phase, MYKKE was opened in June 2014 as a prospective multi-center registry for patients from pediatric heart centers, university hospitals and community hospitals in Germany. The German Competence Network for Congenital Heart Disease provides administrative and logistic support. Inclusion criteria include age < 18 years, hospitalization for suspected myocarditis and written consent. Ethical approval was obtained by local authorities of all collaborating centers.

Results: By August 31, 2015, 15 centers across Germany are actively participating and have enrolled 122 patients with an average rate of 5 to 10 patients per month since summer 2014. Baseline data show clear trends for age: 0 to 2 years (n = 28/122; 22%), 2 to 12 years (15/122; 13%), and 13 to 18years (n = 79/122; 65%); gender: male (79/122; 65%) of cases. Decrease of exercise capacity (n = 85) was the leading symptom, followed by angina (n = 51), dyspnea (n = 45), arrhythmia (n = 35). Syncope and cardiac death was only rare. Patients aged 0 to 2 years had the highest incidence of reduction of ejection fraction below 30% (16/28; 57% of patients) compared with age groups 2 to 12years (22%) and 13 to 18years (8%). VAD therapy was also high in this patient group 22/28 patients (78%) according to > 60% acute heart failure.

Conclusion: MYKKE is a successful multi-center registry, enrolling children and adolescents with suspected myocarditis in Germany. With providing prospective data on age-related clinical features, standard of care and clinical course might be elucidated. The baseline dataset from the initial 122 patients confirms the presence of two age peaks and provides insights into the severity of myocarditis in the youngest. In the future, MYKKE might facilitate interventional studies,for example, in patients with severe heart failure by providing an established collaborating network using common diagnostic approaches among the participating centers.