In 80% of people, which artery supplies the posterior surface and interventricular septum, defining a dominant right heart?

• A. Right coronary artery
• B. Left coronary artery
• C. Circumflex artery
• D. Anterior descending artery

Answer: (A)

Understanding coronary dominance is the key. Dominance is defined by which artery gives rise to the posterior descending artery, the branch that travels in the posterior interventricular groove and supplies the posterior surface of the heart and most of the interventricular septum. In about 80% of people, the posterior descending artery comes from the right coronary artery, so the heart is right-dominant. That means the right coronary artery provides the blood vessels that nourish the posterior surface and the posterior portion of the interventricular septum. In left-dominant hearts, the left circumflex artery supplies the posterior descending artery, and some individuals show a co-dominant pattern where both arteries contribute to the posterior circulation.