This 59-year-old man with severe peripheral vascular disease was in the pre-anaesthesia clinic for assessment prior to his admission for vascular surgery. It was noted that his pulse was very rapid and irregular, despite him being asymptomatic. He was brought to the Emergency Department, where an ECG was recorded:

• Atrial fibrillation with rapid ventricular response (137/min)
• Right superior axis deviation
• Acute lateral infarction
• Inferior-posterior injury pattern

His serum troponin was found to be elevated, and the patient was taken to the cardiac catheterization lab. The ostium of the circumflex artery was significantly narrow, and contained a large clot that was removed with an aspiration catheter. The lesion was dilated and a metal stent was implanted. The left anterior descending and right coronary arteries were patent and free of stenosis. The patient remained free of chest paint, and was transferred to the CCU:

• Sinus rhythm 82/min
• Right superior axis deviation
• Acute lateral infarction
• Posterior injury pattern