Anomalous origin of the left main coronary artery from the right anterior aortic sinus: Angiographic definition of anomalous course

Coronary artery anomalies in 126,595 patients undergoing coronary arteriography

“…8E,F). The anomalous vessei follows a pattern similar to the conus branch with a cranial-anterior loop (43). The LMT then divides at the junction of the proximal and middle thirds of the septum.…”

“…The left main crosses the superior aspect of the crista supraventricularis, passes a variable distance through the septum, and then assumes an epicardial position. This has the appearance of a "hammock" with a caudal-anterior loop seen angiographically (43). The left main becomes epicardial at the midseptum.…”

“…8A,B). Angiographically, in the RAO projection, the left main forms a cranial-posterior loop in its initial course between the aortic root and the right ventricular infundibulum at the pulmonic valve level (43). The left main divides in the proximal septum, and the LAD and CX appear to have normal length.…”

“…In this series, the "septal" subtype was the most common, whereas the "between" type was rare. SG,H) (43). An RAO ventriculogram or aortogram will place the LMT on end, giving the appearance of a "dot" on the posterior aspect of the aorta (44).…”

“…However, the course of initial loops demonstrated in the RAO (and LAO) projections, and the "dot" and "eye" method are helpful in identifying the correct anatomical course (43,44). Exercise testing with myocardial perfusion scanning may identify patients at risk for a future cardiac event, although a normal exercise test does confirm immunity from a future complication.…”