Myocardial covering on epicardial coronary arteries. Prevalence, localization and significance.

Epicardial coronary arteries are on occasion covered by myocardial musculature (mural stretches). Premural segments of the left anterior descendent artery, and only of this artery, seem to be sites of predilection for arteriosclerotic stenosis and for coronary thrombosis. The myocardial covering can be demonstrated angiographically as a "milking effect" and surgical correction consisting of myotomy has recently proved successful.