Towards evidence-based diagnosis of myocarditis in children and adolescents: Rationale, design, and first baseline data of MYKKE, a multi-centre registry and study platform

Aims The aim of this registry is to provide data on age-related clinical features of suspected myocarditis and to create a study platform allowing for deriving diagnostic criteria and, at a later stage, testing therapeutic interventions in patients with myocarditis. Study design and results After an initial 6-month pilot phase, MYKKE was opened in June 2014 as a prospective multi-centre registry for patients from paediatric heart centres, university hospitals and community hospitals with paediatric cardiology wards in Germany. Inclusion criteria consisted of age< 18 years and hospitalisation for suspected myocarditis as leading diagnosis at the discretion of the treating physician. By December 31st 2015, fifteen centres across Germany were actively participating and had enrolled 149 patients. Baseline data reveal two age peaks (< 2 years, >12 years), show higher proportions of males, and document a high prevalence of severe disease courses in paediatric patients with suspected myocarditis. Severe clinical courses and early adverse events were more prevalent in younger patients and were related to severely impaired left-ventricular ejection fraction at initial presentation. Summary MYKKE represents a multi-centre registry and research platform for children and adolescents with suspected myocarditis that achieves steady recruitment and generates a wide range of real-world data on clinical course, diagnostic work-up, and treatment of this group of patients. The baseline data reveal the presence of two age peaks and provide important insights into the severity of disease in children with suspected myocarditis. In the future, MYKKE might facilitate interventional substudies by providing an established collaborating network using common diagnostic approaches. Trial registration ClinicalTrials.gov NCT02590341