Two infants were referred to the emergency ward: a 3.5-month-old male infant in whom sweating and shortness of breath were seen during drinking and crying, and a 5-week-old girl that had drunk less the past day, moaned while breathing for the past few hours and had become increasingly drowsy. They were not suffering from an infection but from a dilated cardiomyopathy based on an anomalous origin of the left coronary artery from the pulmonary artery. The left coronary artery was then implanted in the aorta surgically. Both patients recovered well. Airway tract infection and sepsis are obvious common differential diagnostic considerations when confronted with a tachy-dyspnoeic infant. However, a cardiac cause, such as a dilated cardiomyopathy with cardiac decompensation, must also be considered as the presentation can be similar. The abnormal origin of the left coronary artery from the pulmonary artery is one of the few readily well treatable causes.