Clinical Presentation and Therapy of Coronary Artery Anomalies.

There are two major coronary arteries that arise normally directly above the aortic valve in the sinus. The left main coronary artery (LCA or LMCA) arises from the left coronary sinus and divides shortly after its origin into the left anterior descending and the circumflex coronary arteries (LCX). Branches of the left anterior descending (LAD) coronary artery include the left conus, septal, and diagonal arteries. Branches of the circumflex coronary artery may include the sinus node artery, Kugel's artery, marginal arteries, and the left atrial circumflex artery (Fig. 47.1). The LAD follows the interventricular septum to the apex, the LCX turns posterior, follows the atrioventricular groove between the left atrium and ventricle to the coronary sinus. Branches of the right coronary artery (RCX) include the conal branch, the sinus node artery, an atrial branch, the right ventricular muscle branches (including the acute marginal branch), the posterior descending coronary artery, the atrioventricular node artery, and septal branches (Fig. 47.2). The RCX follows the atrioventricular groove between the right atrium and ventricle. The "dominant coronary artery" is the one giving rise to the posterior descending coronary artery. It originates from the right coronary artery in 80% of people.