Mitochondrial A3243G Mutation With Manifestation of Acute Dilated Cardiomyopathy

A 35-year-old woman (body mass index, 16 kg/m 2 ; height, 140 cm) presented to the emergency ward with severe dyspnea of acute onset.The medical history was noteworthy for bilateral hypacusis treated with a hearing aid.On admission, the laboratory results revealed an N-terminal prohormone of brain natriuretic peptide level of 10 219 ng/L (normal Ͻ200 ng/L).Thoracic CT scan excluded pulmonary embolism but showed cardiomegaly with pericardial and bilateral pleural effusion suggesting the presence of acute heart failure.Cardiac MRI (CMR) demonstrated a severely reduced left ventricular ejection fraction (LVEF, 13%) and severe right ventricular dysfunction (Figure 1A and 1B, baseline); LV mass index was normal.Late gadolinium enhancement images demonstrated extensive subepicardial lesions in inferior and lateral LV segments (Figure 1C, baseline).The angiogram excluded a coronary pathology, and myocardial histology was without histological signs of infiltrative or active inflammatory disease.The ECG was noteworthy for a shortened PQ interval, but supraventricular tachycardia was not revealed during long-term ECG monitoring.Otherwise, the patient showed a hyperglycemic fasting glucose level (7.5 mmol/L; normal Ͻ5.6 mmol/L), and, whereas lactate level was normal at rest (2 mmol/L; normal Ͻ2.4 mmol/L), a rapid increase to 4.3 mmol/L was noteworthy after 150 seconds of bicycle exercise at 35 W. Cerebral MRI showed cerebellar atrophy (Figure 2) in the absence of a clinically relevant neurological disorder, and ophthalmologic examination revealed bilateral ocular maculopathy.With standard heart failure therapy including low-dose ␤-blockade, angiotensin-converting enzyme inhibition, aldosterone blockade, and loop diuretics, the patient recovered to New York Heart Association class II; in parallel, the NT-proBNP-level decreased to 391 ng/L.After 18 months, CMR showed significant improvement of systolic biventricular function (LVEF, 48%; minor right ventricular dysfunction) (Figure 1D and 1E), whereas volume and pattern of the myocardial lesions remained unchanged (Figure 1F).