A 16 year old boy with chest pain

A 16 year old boy awoke with a crushing pain in the centre of his chest. He was clammy, nauseated, and vomited once. He had a history of antiphospholipid syndrome and had been prescribed low molecular weight heparin injections. He admitted to being poorly adherent to this treatment before presentation. He also had hypertension, which was thought to be secondary to poor blood supply to a shrunken, poorly functioning right kidney. He was a smoker and occasional user of cocaine and amphetamines, but he had not used either illicit drug for at least two weeks before the event. An ambulance was called, and the paramedics performed electrocardiography⇓. ### 1. What does his electrocardiograph show? #### Short answer Sinus rhythm at 58 beats/min, normal axis, ST elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL. Appearances are consistent with an inferior ST elevation myocardial infarction (STEMI). #### Long answer Sinus rhythm at 58 beats/min, normal axis, ST elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL. There is also T wave inversion in leads V1, V2, aVR, and aVL (fig 2⇓). Fig 2 Electrocardiograph showing ST elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL The electrocardiograph indicates an inferior STEMI. The right coronary artery supplies the inferior surface of the heart in around 85% of cases. The left circumflex artery supplies the inferior surface of the heart in the remaining 15% of patients. The table⇓ gives details of the coronary artery …