CLINICAL MEDICINE

Detailed explanation-1: -The sinoatrial node is supplied by the atrial branch of the proximal right coronary artery (RCA) in 55% of cases and the proximal left circumflex artery in 45% of cases. The RCA perfuses the AV node and the proximal portion of the His bundle in most cases (left circumflex artery in 10% of cases).

Detailed explanation-2: -The right coronary artery supplies blood to the right ventricle, the right atrium, and the SA (sinoatrial) and AV (atrioventricular) nodes, which regulate the heart rhythm. The right coronary artery divides into smaller branches, including the right posterior descending artery and the acute marginal artery.

Detailed explanation-3: -It most commonly originates from the right coronary artery (68% of patients) and less commonly from the left coronary artery and left circumflex artery (24.7% of patients).

Detailed explanation-4: -The sinoatrial node was supplied by a unique source represented by the right coronary artery in 37 cases (74%) and by the circumflex artery in 8 cases (16%), and by a double source represented by two branches of the right coronary artery in 2 cases (4%) and of both coronary arteries in 3 cases (6%).

Detailed explanation-5: -The right coronary artery (RCA) traces along the right coronary sulcus and provides blood flow to the anterior and diaphragmatic surfaces of the right atrium and ventricle; as well as the posterior two-thirds of the interventricular septum.