A 5-month-old girl was admitted to our paediatric intensive care unit with cardiorespiratory failure and hypertension. Chest radiography showed cardiomegaly and pulmonary plethora. Electrocardiography showed left ventricular hypertrophy and strain pattern. Echocardiography showed a dilated and hypertrophied left ventricle, with bright and hyper-reflective myocardium (fig 1). Fractional shortening was 12.5%. The concentration of creatine kinase was 493 U/l (normal range 20–190) and that of troponin …