Asymptomatic anomalous left anterior descending artery arising from the right coronary artery with a rare anterior course.

The presence of a malignant course on the coronary circulation is the second leading cause of sudden cardiac death in young adults. One type of malignant conformation is an anomalous left anterior descending artery (LAD) arising from the right coronary artery (RCA). In a study examining 70 850 patients undergoing coronary angiography, the prevalence of this anomaly was noted in 0.006% of total patients and in 2.3% of congenital coronary anomaly cases. Of the four patients presenting with this anomaly, only one was noted to have an interarterial course of the LAD between the aorta and pulmonary artery. We describe the case of a patient who was incidentally found to have a malignant anomalous LAD arising from the RCA when he presented with a non-ST elevation myocardial infarction due to a ruptured plaque in an obtuse marginal branch. This patient survived for 57 years with no symptoms.