A 3-month-old girl presented to a paediatric emergency department with respiratory distress, growth failure, irritability and difficulty in feeding. On clinical examination, she had tachypnea, chest retractions, tachycardia and hepatomegaly, while her chest radiograph revealed cardiomegaly. Deep Q waves were present from V2 to V5 on the electrocardiographic tracings, with diffuse repolarization changes. Echocardiography showed severe dilation of the left ventricle and poor global systolic left ventricular function, with a shortening fraction of 10% and moderate mitral regurgitation. Colour coded Doppler interrogation (Fig. 1) demonstrated reversal of flow through the left coronary artery (large arrow), with the blood entering the pulmonary trunk (small arrow), consistent with anomalous origin of the left coronary artery from the pulmonary trunk. Imaging in this case also showed with unusual clarity the more rarely observed high-speed flow in the ventricular septum (Fig. 2), representing reversed flow in the septal coronary arteries. A myocardial perfusion scan with thallium provided further evidence of diffuse myocardial hypoperfusion.

The patient underwent surgical correction by translocation of the left coronary artery to the ascending aorta. The procedure was uneventful, and a gradual increase in left ventricular function was observed, allowing discharge on the sixteenth day after surgery.

As illustrated by this case, echocardiography can provide the definitive diagnosis of anomalous origin of the left coronary artery by demonstrating its abnormal origin and trajectory, as well as dilation of the right coronary artery, a dilated and globally hypokinetic left ventricle, and mitral regurgitation.¹