• Images in cardiology

A 51 year old diabetic presented with a five hour history of severe chest pain at a community hospital. The ECG showed an acute anterolateral wall myocardial infarction and the patient was treated with intravenous tissue plasminogen activator (t-PA). Because of postinfarction angina, he was referred for coronary angiography.

Selective coronary angiography revealed an unusual coronary artery anomaly. The dominant right coronary artery (RCA) arose from the appropriate sinus of Valsalva. However, an ectopic left anterior descending coronary artery (LAD) was seen to originate from the proximal part of the right coronary artery (see diagram: RCA, right coronary artery; RVB, right ventricular branch; S, septal artery; LAD, left anterior descending artery; LCx, left circumflex artery. Interrupted lines indicate intramural course). After giving off a small right ventricular branch, the ectopic LAD passed intramuscularly through the interventricular septum before reaching an epicardial position at the mid septum. Within the septum, the ectopic LAD formed a caudal–anterior loop which gave a characteristic “hammock” appearance in the RAO projection (video sequence 1, freeze frame below diagram). Later, the ectopic LAD began its descent in the anterior interventricular groove adjacent to a 180° loop in a second LAD (see below), which originated from the left sinus of Valsalva.

This second LAD originating from the left anterior sinus of Valsalva ran in the proximal third of the interventricular groove and gave rise to a large, diffusely diseased diagonal branch. Later, the LAD gave off a small septal branch, and then turned upward in a 180° loop which contained a subtotal stenosis. This ascending part of the LAD, an anomalous origin of the left circumflex artery (LCx), proceeded to cross the diagonal branch and then entered the AV groove where it divided into two branches supplying the lateral wall of the left ventricle (video sequences 2 and 3, freeze frames in right hand column). Thus, the proximal LAD followed a highly anomalous course into the LCx.

All coronary arteries showed diffuse narrowings in their distal segments. The subtotal stenosis in the 180° loop of the anomalous LAD-LCx transition was successfully treated by angioplasty.

Coronary artery anomalies occur in 0.2–1.2% of the population. The most common anomalies involve either a retro-aortic coursing LCx arising from the right coronary cusp or the RCA, or alternatively an RCA arising from the left coronary cusp. These two anomalies account for 72% of all coronary artery anomalies. The LAD originates from the right aortic sinus in 2.3% of patients without congenital heart disease and coronary artery anomalies. There is only one prior report of a bilaterally originating split LAD in the literature; however, this was not associated with an anomalous origin of the LCx, which is presented here for the first time.