An ill 16 days old baby girl is brought to the emergency. On examination pallor and dyspnoea present with a respiratory rate of 85 per minute. Her HR is 200 bpm, hea sounds are distant and a gallop is heard. X-ray showed cardiomegaly. An echocardiogram shows dilated ventricles and dilation of the left atrium. An ECG shows ventricular depolarization complexes that have low voltage. Which of the following is the most likely diagnosis?