Profound myocardial ischemia associated to occlusion of the right coronary artery

A 75-year-old man with hypertension, hypercholesterolemia and history of coronary artery disease was admitted to the hospital because of sudden loss of consciousness. The patient suffered an acute myocardial infarction seven years before this admission, which was treated with percutaneous transluminal coronary angioplasty and stent implantation in the right coronary artery. The initial electrocardiogram showed a complete atrioventricular block, with narrow ventricular complexes at a rate of 40 bpm. The next electrocardiogram, obtained after the administration of atropine, showed a sinus rhythm at 84 bpm with first-degree atrioventricular block, obvious ST-segment elevation on leads II, III, aVF, V3 to V6, and electrical alternation of the ST-segment. Subsequently, he suffered three episodes of ventricular fibrillation which were successfully defibrillated. The ST-segment elevation improved after sublingual nitroglycerine and the patient underwent urgent coronary angiography, which showed a critical stenosis in the middle part of the right coronary artery with a lot of thrombus material in the site of the previous stent. The rest of the coronary arteries did not reveal significant lesions. Thrombus aspiration and balloon angioplasty were successfully performed without residual stenosis. The ST-elevation alternans is a rare phenomenon which was initially described in the setting of coronary artery spasm. It is believed to be associated to profound myocardial ischemia, particularly in relation with occlusions of the left anterior descending coronary artery, and to the occurrence of malignant ventricular arrhythmia and sudden cardiac death.