Beta blockers after MI: safe for the few, still relevant for the many

The role of beta blockers after myocardial infarction (MI) in the reperfusion era has been challenged by four major contemporary randomised controlled trials: REDUCE-AMI1, AβYSS2, REBOOT3 and BETAMI-DANBLOCK4, which together with the older CAPITAL-RCT5 enrolled more than 23,000 patients across 10 countries. This represents a major accomplishment for the academic community. Results, however, remain heterogeneous. CAPITAL-RCT (801 patients) was stopped prematurely and showed only a non-significant trend towards a benefit of carvedilol. REDUCE-AMI (5,020 patients) and REBOOT (8,438 patients) both reported neutral results, with no difference in death or MI. In contrast, BETAMI-DANBLOCK (5,574 patients) found a significant reduction in a larger composite outcome of death from any cause, MI, unplanned coronary revascularisation, ischaemic stroke, heart failure, or ventricular arrhythmias with continued beta blocker therapy, while AβYSS (3,698 patients), which specifically tested withdrawal after chronic use, showed more reinfarctions and hospitalisations in the withdrawal arm. These divergences have fuelled ongoing debate between advocates and sceptics.

The first consistent finding across trials is that beta blockers at contemporary doses are well tolerated. While historically considered poorly tolerated,...