Update on Baseline Data and First 1-Year Follow-up of the German Multicenter Myocarditis Registry for Pediatric Patients: “MYKKE”

Objectives: There are only few data on epidemiology, diagnosis and therapy of myocarditis in children and adolescents. Our first data revealed a high incidence of young children with severe heart failure, maybe due to immunological differences. With our new data we confirm the first baseline data on age-related clinical differences in this patient group and show for the first time follow up data.

Methods: After an initial 6-month pilot phase, MYKKE was opened in June 2014 as a prospective multicenter 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 4, 2016, a total of 17 centers across Germany are actively participating and have enrolled 193 patients. Baseline data show clear trends for age: 0-< 2 years (45/193; 23%), 2–12 years (36/193; 19%) and 13–18 years (112/193; 58%); gender: male (130/193) 67% of cases. Decrease of exercise capacity (72%) was the leading symptom, followed by angina (38%), dyspnea (38%), arrhythmia (30%) and syncope (14%). Sudden cardiac death was only rare (2%). 55% had an infection less than 6 weeks ago, respectively 35% fever. Patients 0-< 2 years had again the highest incidence of reduction of ejection fraction (EF) below 30% (25/46; 56%) compared with age groups 2–12 years (43%) and 13–18 years (9%). Furthermore they had the highest need for VAD therapy (10/45, 22%) according to 53% patients with acute heart failure. Most children died in the 2–12 years group (4/36; 11%). The overall mortality is 3.6% (7/193). By now we have the follow up data of 45 patients (45/193; 23%) with a mean time of 10 ± 5 month after the first visit. The mean EF was 46 ± 19.7% at initial presentation, which increased to 60 ± 13.8% at follow up.

Conclusion: With its ongoing enrollment, MYKKE is a successful multi-center registry for myocarditis in children and adolescents. The data underline two age peaks with a severe clinical course and more adverse events in the youngest patients. MYKKE serves as a platform for deriving diagnostic criteria and will later facilitate interventional studies.

No conflict of interest has been declared by the author(s).