Anomalous origin of the left anterior descending coronary artery from the pulmonary trunk.

An extremely rare congenital abnormality is reported in which the anterior descending branch of the left main coronary artery arises independently from the pulmonary trunk in a young patient who presented with unstable angina. Its clinical presentation, angiographic identification and surgical treatment are described. It appears to be a distinct entity with few of the features of the classical form of anomalous origin of the left main coronary artery.