A 10-year-old girl being evaluated for cardiomegaly.

This 10-year-old girl was transferred from an outside hospital for evaluation of cardiomegaly. She had been well until several weeks before admission when she started complaining of increasing fatigue and dyspnea on exertion. Three days before admission, she developed a dry cough and left-sided chest pain, without any fever or viral symptoms. Review of systems was otherwise unremarkable. Past history and family history were unremarkable. On exam, she was an alert, healthy-appearing, somewhat anxious girl. Weight was in the 50th percentile, and height was in the 15th percentile. Pulse was 104, respiratory rate 35, blood pressure 106/45, pulse oximetry 99% in room air. She was not dysmorphic. HEENT exam was unremarkable. Lungs had good aeration bilaterally with bibasilar crackles. S1 and S2 were normal without murmurs, rubs, or gallops. Abdomen was soft without masses or organomegaly. She was Tanner 1. Pulses were 2+ bilaterally. Neurologic exam was unremarkable. Chest X-ray revealed cardiomegaly with increased interstitial markings. Echocardiogram demonstrated severely depressed biventricular systolic function, a moderately di-