Are beta blockers still necessary for all survivors of acute myocardial infarction?
In the previous decades, a huge number of clinical randomized controlled trials showed that beta blockers (BB) reduced incidence of all-cause death and adverse cardiac events in patients with acute myocardial infarction (AMI) (1-5). The Beta-blocker Heart Attack Trial (BHAT), which examined the efficacy of propranolol treatment initiated 5–21 days after AMI, showed that mortality was reduced by 25% during a mean follow-up period of 2 years (7% vs. 9.5%, respectively) (2,3). Similarly, the Norwegian trial, in which beneficial effect of timolol treatment from 6–27 days following AMI was examined, demonstrated nearly 40% reduction of mortality at 33 months (from 21.9% to 13.3%) (1). Furthermore, meta-analyses showed significant risk reduction via BB therapy for long-term mortality of post-AMI patents by 25% and 23% in the pre-reperfusion (6) and thrombolytic eras (7), respectively. Based on these findings, with respect to the of BB in the secondary prevention settings after ST-elevation myocardial infarction (STEMI), the ACCF/AHA guideline for the management of STEMI recommends BB should be continued during and after hospitalization for all patients with STEMI and with no contraindications to their use as a class I indication. Whereas, European Society of Cardiology (ESC) (8) as well as Japanese Circulation Society (JCS) (9) guidelines recommend BB use, in the absence of contraindications, in patients with reduced systolic left ventricular (LV) function [LV ejection fraction (EF) ≤40%] as a class I, and routine use of BB in all patients as a class IIa indication.