What artery supplies the back of the heart?

Blood Supply to the Back of the Heart

The posterior (back) of the heart is primarily supplied by the posterior descending artery (PDA), which arises from the right coronary artery (RCA) in approximately 85-90% of individuals (right-dominant circulation), and by posterolateral branches that also typically originate from the RCA. 1, 2

Arterial Supply Based on Coronary Dominance

The blood supply to the posterior heart depends on coronary dominance patterns:

Right-Dominant Circulation (85-90% of people)

• The RCA supplies the PDA and posterolateral branches, which together perfuse the inferior wall of the left ventricle and posterior interventricular septum 1, 2
• The PDA runs in the posterior interventricular groove and gives off septal perforator branches that supply the posterior one-third of the interventricular septum 1, 3
• The posterolateral segmental artery represents the distal continuation of the RCA in the posterior atrioventricular groove after the PDA origin 1
• Multiple posterolateral branches (first, second, and third) arise from the right posterior atrioventricular artery to supply the posterior and lateral walls 1

Left-Dominant Circulation (10-15% of people)

• The PDA and posterolateral branches arise from the left circumflex artery instead of the RCA 1, 4
• The left circumflex continues as the left atrioventricular artery in the posterior atrioventricular groove 1

Co-Dominant Circulation

• The RCA supplies the PDA while the circumflex artery supplies the posterolateral branches, with both arteries contributing to the inferior wall blood supply 1

Specific Posterior Structures and Their Supply

• Inferior wall of left ventricle: Supplied by PDA and posterolateral branches from the dominant system 2
• Posterior interventricular septum: Supplied by septal perforators from the PDA 1, 3
• Right ventricle posterior wall: Supplied by right ventricular branches from the RCA 1

Clinical Significance

Understanding posterior heart blood supply is critical because:

• Inferior wall myocardial infarctions typically result from RCA occlusion in right-dominant systems, affecting the PDA territory 2
• The posterior septum is vulnerable to ischemia from PDA compromise, which can lead to ventricular septal rupture (occurring in 1-2% of MIs with 54% mortality in the first week without surgery) 3
• Coronary aneurysms commonly occur in the proximal RCA, which supplies these posterior structures 2