Learning Cardiology

Q. Myocardial infarction in case of aortic dissections most commonly involve? A. LAD territory B. RCA territory C. LCx territory D. Ramus intermedius territory Answer: B. RCA territory Explanation:  Aortic dissections when extending to aortic root, may involve coronary arteries and cause myocardial infarction. Most commonly involved coronary artery in aortic dissections is right coronary artery.

Q. In left dominant circulation, which of the following is not a branch of left circumflex artery? A. AV nodal artery B. Obtuse marginal artery C. Posterolateral branches D. Conus artery Answer: D. Conus artery Explanation: In right dominant circulation, AV nodal and posterolateral branches arise from RCA whereas in left dominant circulation they arise from left circumflex artery. In codominant circulation, AV nodal artery arise from RCA and posterolateral branches arise LCx. Obtuse marginal arteries are branches of left circumflex and acute marginal arteries are branches of right coronary artery. Origin of conus artery is not affected by dominance of cardiac circulation. It arises from RCA and supplies the right ventricular outflow tract. Sometimes, it may directly arise from left main coronary artery.