Transient but marked ST elevation in precordial leads caused by ischemia of the isolated right ventricular branch

The present case is a 64 year-old man in whom transient but marked ST elevation was confirmed in the contralateral precordial leads (V1-3) during percutaneous transluminal coronary angioplasty (PTCA) of the proximal right coronary artery, suggesting that the patient had anteroseptal ischemia. The ST elevation persisted even after the balloon was deflated, and no changes in the left coronary artery were detected. In addition, blood flow in the affected area of the right coronary artery was favorable and there was a transient delay only in the right ventricular branch. Once blood flow in the right ventricular branch improved, ST returned to baseline, and when the right ventricular branch was again occluded by the balloon, ST elevation occurred in a reproducible manner. Hence, the electrocardiographic changes in the precordial leads were caused by occlusion of the right ventricular branch. It is rare to observe ST elevation caused by isolated right ventricular branch ischemia.