A 66-year-old man comes to the hospital due to sudden-onset chest pain and dyspnea. The patient has a history of asthma and gastroesophageal reflux disease but says his current symptoms feel different than what he usually experiences. An ECG is consistent with ST-elevation myocardial infarction, and an emergent cardiac catheterization is performed. Evaluation of the left and right coronary arteries reveals left-dominant circulation. A stenotic region is identified in one of the coronary vessels just before the origin of the artery supplying the atrioventricular node. Which of the following arteries is most likely affected?

Question

A 66-year-old man comes to the hospital due to sudden-onset chest pain and dyspnea.  The patient has a history of asthma and gastroesophageal reflux disease but says his current symptoms feel different than what he usually experiences.  An ECG is consistent with ST-elevation myocardial infarction, and an emergent cardiac catheterization is performed.  Evaluation of the left and right coronary arteries reveals left-dominant circulation.  A stenotic region is identified in one of the coronary vessels just before the origin of the artery supplying the atrioventricular node.  Which of the following arteries is most likely affected?

Quizplus · Accepted Answer

11ec160b_355a_b165_9249_99e1495cda3a_MD0001_00 Coronary dominance is determined by the coronary artery that supplies blood to the posterior descending artery (PDA [or posterior interventricular artery]). The PDA originates from one of the following: The atrioventricular (AV) nodal artery most often arises from the dominant coronary artery. This patient has left-dominant coronary circulation; therefore, his atherosclerotic lesion is most likely in the left circumflex artery. Involvement of the AV nodal artery during myocardial infarction can cause varying degrees of AV block. (Choice A) The left anterior descending artery travels in the anterior interventricular groove and supplies the anterior part of the septum and the anterior wall of the left ventricle. It does not supply the AV node. (Choice C) The diagonal arteries arise from the left anterior descending artery and supply the anterolateral wall of the left ventricle. (Choice D) The right coronary artery gives rise to the AV nodal artery in patients with right-dominant or codominant circulation. This patient has left-dominant circulation, so the AV node is most likely supplied by the left circumflex artery. (Choice E) The right marginal arteries arise from the right coronary artery and supply blood to the free wall of the right ventricle. Educational objective: Coronary dominance is determined by the coronary artery supplying the posterior descending artery. The posterior descending artery originates from the right coronary artery in approximately 70%-80% of patients (right dominant), both the right coronary and left circumflex artery in 10%-20% (codominant), and the left circumflex artery in 5%-10% (left dominant). The dominant coronary artery supplies blood to the atrioventricular (AV) node via the AV nodal artery. __________ References: Anatomical aspects of the arterial blood supply to the sinoatrial and atrioventricular nodes of the human heart. (http://www.ncbi.nlm.nih.gov/pubmed/18652764)

A 66-Year-Old Man Comes to the Hospital Due to Sudden-Onset