Serial right ventricular endomyocardial biopsy in rapid-onset severe heart failure due to giant cell myocarditis.

Giant cell myocarditis (GCM) is a serious condition that warrants immediate diagnosis and treatment. It often presents as rapidly progressive heart failure and/or malignant ventricular arrhythmias. Here, we describe a 34-year-old patient with myasthenia gravis who presented with GCM 2 weeks after resection of a thymoma. A cardiac biopsy confirming the diagnosis was done within 3 days after admission. After institution of an aggressive immunosuppressive drug regimen, implantation of an implantable cardioverter defibrillator, and intensive cardiac rehabilitation, the patient recovered dramatically. In control biopsies after 4 weeks and 6 months, no more giant cells were found. We conclude that, in the case of nonischemic acute heart failure in young patients, a biopsy should be performed as soon as possible to prevent an unfavourable outcome of this often fatal disease.