CARDIAC ANATOMY

The left internal mammary artery supplies the anterior chest wall. It has been shown to be superior to saphenous vein grafts (from aorta to LAD) in staying patent and hence is now the choice artery (LIMA to LAD) graft. Although circumflex and right coronary arteries are usually grafted with veins, the right internal mammary arteries (RIMA) are sometimes used to graft the RCA.

The circumflex artery gives off obtuse marginal branches and the LAD gives off diagonal branches.

The intermediate artery is not always present, it is a variant artery which is between the LAD and circumflex artery, and occasionally dominant instead of the circumflex.

The coronary sinus predominantly drains venous blood from the left ventricle and receives approximately 85 percent of coronary venous blood. It receives blood from the the marginal, posterior left ventricular, anterior interventricular veins and the great cardiac vein. The blood finally drains into the right atrium.

The posterior descending artery is often (85%) a branch of the right coronary artery. The sinus node artery is a branch of the right coronary artery in 60% of cases.

The AV node is supplied by the posterior descending coronary artery.