Application of left ventricular endomyocardial biopsy in the diagnosis of mitochondrial cardiomyopathy: a case report

BACKGROUND: The clinical features of mitochondrial cardiomyopathy (MCM) are diverse. It can present as hypertrophic cardiomyopathy or dilated cardiomyopathy. The diagnosis of MCM is challenging and usually based on biopsy. CASE PRESENTATION: The 30-year-old man was admitted to hospital due to dyspnea for 1 month and edema of both lower extremities for 1 week. Echocardiography suggested a whole heart enlargement, a whole heart diminished function. Renal impairment and diabetes were observed. Coronary angiography showed single-vessel disease (90% stenosis in the ostium of a small marginal branch). Left ventricular endomyocardial biopsy was performed. CONCLUSION: Myocardial histopathology demonstrated a large number of abnormal mitochondrial accumulation, so the diagnosis was considered as mitochondrial cardiomyopathy.