Influence of left ventricular systolic function on the long-term benefit of beta-blockers after ST-segment elevation myocardial infarction

Introduction: Beta-blockers are recommended after ST-elevation myocardial infarction (STEMI), but their benefit in patients with preserved left ventricular ejection fraction (LVEF) is unclear. Methods: Consecutive patients discharged in sinus rhythm after STEMI between January 2010 and April 2015 were followed until December 2017. Percutaneous coronary intervention (PCI) was performed in 969 (99.7%, including 112 with rescue PCI) and three (0.3%) received only thrombolytic therapy without rescue PCI. Results: Of these 972 patients, mean age 62.6 +/- 13.5 years, 212 (21.8%) were women and 835 (85.9%) were prescribed beta-blockers at discharge. Patients who did not receive beta-blockers had more comorbidities than those who did, including chronic obstructive pulmonary disease (14.6% vs. 4.2%), anemia (8.0% vs. 3.7%), and cancer (7.3% vs. 2.8%), and more frequently had inferior STEMI (75.9% vs. 56.0%) and high-grade atrioventricular block (13.1% vs. 5.3%) (all p<0.01). After a mean follow-up of 49.6 +/- 24.9 months, beta-blocker treatment at discharge was independently associated with lower mortality (HR 0.61, 95% confidence interval [CI] 0.38-0.96, p=0.03). This effect was present in 192 patients with LVEF <= 40% (HR 0.57, 95% 95% CI 0.34-0.97, p=0.04) but was not clear in 643 patients with LVEF >40% (HR 0.67, 95% 95% CI 0.25-1.76, p=0.42). Conclusion: In the LVEF >40% group, the results raise reasonable doubts about the real benefit of systematic use of beta-blockers as treatment for these patients. These findings reinforce the need for large randomized clinical trials within this group of patients. (C) 2021 Sociedade Portuguesa de Cardiologia. Published by Elsevier Espana, S.L.U.