A 65-year-old man complaining of a 20 min history of non-radiating, retrosternal chest pain was attended by a paramedic within 10 min of the emergency call. Cardiac risk factors included hypertension, hypercholesterolaemia and a family history of ischaemic heart disease. Medical history revealed dextrocardia. Clinically he was pale and diaphoretic with nausea. Non-invasive blood pressure was 128/86 mm Hg, pulse rate 64 beats/min, respiratory rate 12 breaths/min and oxygen saturations were 100%. Supplemental oxygen, aspirin (300 mg orally) and glyceryl trinitrate (400 μg sublingual) were administered. A 12 lead electrocardiogram (ECG) was performed with routine positioning of the limb leads and reversal of the precordial leads (V1R–V6R) (fig 1). Due to the dextrocardia, assistance was requested in the interpretation of the ECG. The ambulance was …