There are only three inclusion criteria for inclusion in Mykke:
1. suspected myocarditis must be (have been) the reason for treatment.
2. patients must be younger than 18 years of age
3. the parents or legal guardian(s) must have given their consent.
This means that Mykke does not specify any fixed criteria for the diagnosis of myocarditis.
Rather, the suspected diagnosis of myocarditis is made by the treating physicians according to their criteria.
Further information on the procedure can be found here.