Malignant single-origin coronary arteries arising from a left coronary sinus.

A 2-month-old boy with a heart murmur and suspected coronary artery anomalies presented for cardiac computed tomography to delineate the origin and course of these anomalies. A single-origin coronary artery was discovered, which arose from the left coronary sinus and coursed between the two outflow vessels, giving this single origin a potentially malignant course. This vessel then went on to split into right and left coronary arteries with normal anatomic distribution. Without the ability for collateral flow, this vessel was located in an extremely precarious position prone to compression during times of stress or exercise. Very rarely has a single-origin coronary artery supplied both ventricles, and even more astonishing was the presence of its interarterial course. This patient will need long-term follow-up care and undoubtedly will be a candidate for surgery to correct this rare potentially malignant anomaly to lessen the boy's chances of sudden cardiac death.