Background: Myocarditis is defined as an inflammatory or infectious disease of the myocardium causing damage through production of a toxin or by immunologically mediated destruction. A rare type is idiopathic giant cell myocarditis.
Material and methods: We present data from Rikshospitalet University Hospital in Norway, with two case reports and a discussion of the diagnostics and treatments currently available. The investigation is retrospective and includes 11 patients, two women and nine men with histologically verified idiopathic giant cell myocarditis.
Results: Median age was 46; four patients had autoimmune co-morbidity. The major onset symptom was rapid progressive heart failure; 64% had concomitant ventricular arrhythmias. Five patients received immunosuppressives in addition to conventional treatment for heart failure. Eight underwent cardiac transplantation and two patients had recurrence of idiopathic giant cell myocarditis in the graft. Mean interval from time of diagnosis to death or cardiac transplantation was six months.
Interpretation: Idiopathic giant cell myocarditis is a rare inflammatory disease of the myocardium that often affects previously healthy young adults. Co-morbidity with autoimmune disorders has been reported. Idiopathic giant cell myocarditis is characterised by a history of rapid progression of severe heart failure associated with refractory ventricular arrhythmias. The diagnosis is made by endomyocardial biopsy. Treatment includes immunosuppressives, and the indication for cardiac transplantation should be evaluated early, as one should bear in mind an increased risk of recurrence in the graft.