In most people, the right coronary artery ( RCA ) supplies most of the SA and AV nodes, as well as the right ventricle and inferior or diaphragmatic portion of the left ventricle. Patients with obstruction of the RCA often have inferior wall MIs. About half of all inferior wall MIs are associated with an occlusion of the RCA causing significant damage to the right ventricle. Thus it is important to obtain a “right-sided” ECG to assess for right ventricular involvement.