The heart receives its blood supply from the coronary arteries. The two main coronary arteries branch off the trunk of aorta close to the aortic va;ve. Coronary arteries receives blood from aorta during diastole when ventricles are resting. Right coronary artery extends to the right and perfuses the right atrium and right ventricle. The SA node is perfused by RCA in approximately 55% and AV node supplied by RCA in 90% of populatio. The remaining percent is supplied by left circumflex.