What arteries supply the heart?

Coronary Arterial Blood Supply to the Heart

Primary Arterial System

The heart is supplied by three major coronary arteries: the left anterior descending (LAD) artery, the circumflex artery, and the right coronary artery (RCA). 1

Left Coronary Artery System

• The left main coronary artery originates from the left aortic sinus and bifurcates into two major branches: the LAD and the circumflex artery 1
• The left main ostium includes the first 3 millimeters of the artery 2
• The LAD artery is one of the primary epicardial coronary arteries that supplies the anterior surface of the heart 2
• The circumflex artery courses along the left atrioventricular groove and gives off obtuse marginal branches to supply the lateral wall of the left ventricle 3

Right Coronary Artery System

• The RCA arises from the right aortic sinus and primarily supplies the right atrium, right ventricle, sinoatrial node, posterior portion of the interventricular septum, and in right-dominant circulation (approximately 90% of people), the inferior wall of the left ventricle 4
• The RCA gives rise to the posterior descending artery (PDA), which runs in the posterior interventricular groove and supplies septal perforator branches 2, 4
• The posterolateral segmental artery represents the distal continuation of the RCA in the posterior atrioventricular groove after the origin of the PDA in right-dominant hearts 2, 4
• Right ventricular branches arise from the RCA to supply the right ventricular wall 2, 4

Coronary Dominance Patterns

Coronary dominance is determined by which artery supplies the PDA and posterolateral branches to the inferior wall of the left ventricle. 2

• Right dominance (most common): The PDA and posterolateral arteries arise from the RCA 2
• Left dominance: The PDA and posterolateral arteries arise from the left circumflex artery 2
• Co-dominance: The RCA supplies the PDA while the circumflex artery supplies the posterolateral arteries, with both contributing to the inferior wall blood supply 2

Specialized Conduction System Supply

• The sinoatrial node is most commonly supplied by the RCA in approximately 60-74% of cases 5
• Damage to the sinus node coronary artery during surgical procedures or interventions can result in atrial arrhythmias and sinus node dysfunction 2, 5

Clinical Significance

• These coronary arteries run subepicardially along the heart surface and provide the sole source of oxygenated blood to the myocardium 1
• Coronary blood flow can increase from resting level to maximum level in response to exercise and other stimuli, a capacity termed coronary flow reserve 1
• Atherosclerotic narrowings produce epicardial vessel resistance and can abolish coronary reserve, reducing resting coronary blood flow and causing myocardial ischemia 1
• Functionally relevant anastomotic vessels (collateral arteries) interconnect epicardial coronary arteries and can provide alternative blood supply in cases of occlusive coronary artery disease 6