• ECG (repeated every 15 min if not initially diagnostic and chest pain persists)
• Chest X-ray
• Creatinine and electrolytes (recheck potassium if significant arrhythmia occurs or after large diuresis)
• Blood glucose (blood glucose >10 mmol/L should be managed by insulin infusion (Chapter 82)
• Troponin level (repeat after 3 h if high-sensitivity assay, after 12 h if standard assay)
• Echocardiography if diagnosis is uncertain, murmur, hypotension or pulmonary oedema

For later analysis

• Full blood count
• Lipid profile (cholesterol value is representative if checked within 24 h of infarction and enables patients with hypercholesterolaemia to be identified before discharge)