A cardiology registrar approaches you briefly in Resus while you are reviewing another unwell patient. He asks for your advice about a 61-year-old man who was admitted with an acute myocardial infarction 4 days ago. The patient is recovering well: he is haemodynamically stable, pain-free, mobilising independently, and his echocardiogram shows normal left ventricular systolic function.

The registrar has started a beta-blocker and is preparing the discharge summary. He wants to ensure the recommended duration of beta-blocker therapy is correct according to NICE MI guidance.

What duration of beta-blocker therapy should be advised for this patient?