Idiopathic giant-cell myocarditis
Idiopathic giant-cell myocarditis (IGCM) is a cardiovascular disease of the muscle of the heart (myocardium). The condition is rare; however, it is often fatal and there is no proven cure because of the unknown nature of the disorder.
Source: Wikipedia — Idiopathic giant-cell myocarditis (CC BY-SA 4.0)