During a right hemicolectomy, a patient develops ST elevation and complete heart block. Which coronary artery is most likely affected?

During a right hemicolectomy, a patient develops ST elevation and complete heart block. Which coronary artery is most likely affected?

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

Answer: (B)

The main idea is how coronary artery anatomy relates to the pattern of ST changes and heart block. The right coronary artery typically supplies the AV node via the AV nodal artery and also supplies the inferior wall of the left ventricle. If a plaque or thrombosis occludes the RCA, regions dependent on it become ischemic, causing ST elevations in inferior leads and, importantly, impairment of AV node conduction. That disruption can produce complete heart block. In most people, this makes occlusion of the right coronary artery the most likely cause of both inferior ST elevations and a high-grade AV block during surgery. (In some left-dominant circulations, the AV nodal supply can come from the left system, but RCA occlusion remains the classic scenario.)

The main idea is how coronary artery anatomy relates to the pattern of ST changes and heart block. The right coronary artery typically supplies the AV node via the AV nodal artery and also supplies the inferior wall of the left ventricle. If a plaque or thrombosis occludes the RCA, regions dependent on it become ischemic, causing ST elevations in inferior leads and, importantly, impairment of AV node conduction. That disruption can produce complete heart block. In most people, this makes occlusion of the right coronary artery the most likely cause of both inferior ST elevations and a high-grade AV block during surgery. (In some left-dominant circulations, the AV nodal supply can come from the left system, but RCA occlusion remains the classic scenario.)