[Atypical presentation of right coronary artery occlusion]

Inferior wall myocardial infarctions are usually benign and uncomplicated and rarely result in ventricular disturbances of the heart rhythm. An unusual presentation of an inferior acute myocardial infarction (AMI) with atypical symptoms, and ventricular tachycardia is described.

A 44-year-old patient was admitted to the coronary care unit (CCU) due to atypical chest pain during exercise and ECG abnormalities in leads L2, L3 and aVF. On admission, ECG could mimic myocarditis, pericardial effusion, left anterior bundle branch block or early repolarization. Two-dimensional echocardiography revealed a hypertrophic myocardium without abnormal regional wall motion, good left ventricular function and ejection fraction of 65%. The presumptive prediction of a culprit artery based on the ECG recorded on admission was conclusive for inferior AMI. Fibrinolytic therapy was started 3 hours after the onset of chest pain. Resolution of ST segment elevation and relief of chest pain occurred within one hour of the infusion. On the fifth day after admission, the patient had a nonsustained ventricular tachycardia (VT) which was resolved with amiodarone. Angiography showed acute occlusion of the mid portion, right coronary artery (RCA) and collateral circulation in the distal portion.

Malignant ventricular arrhythmias can result from isolated inferior wall AMI, but literature reports on this phenomenon are rather rare. Collateral circulation can prevent myocardial ischemia and preserve myocardial function, but does not provide protection against exercise-induced myocardial ischemia.