A 60-year-old female presents with epigastric pain, nausea and vomiting, hea rate of 50, and pronounced first-degree AV block on ER cardiac monitor. Blood pressure is 130/80. The coronary aery most likely to be involved in this process is the

(Fuster, 10/e, pp 52, 88.) The right coronary aery supplies most of the inferior myocardium and supplies the AV node in over 70% of patients. Thus occlusion of this aery can cause ischemia of the AV node with AV block or bradycardia, as well as symptoms of an inferior MI as seen in this patient. AV block can occur with anterior MI related to LAD occlusion, but this generally implies a greater area of myocardial involvement and hemodynamic instability.