# Impact of left ventricular ejection fraction on the effect of beta-blocker therapy on 1-year mortality in acute coronary syndrome patients

## TL;DR

Beta-blocker therapy at discharge reduces 1-year mortality in acute coronary syndrome patients, especially those with a left ventricular ejection fraction of 40% or less.

## Contribution

This study provides evidence that beta-blocker benefits are most pronounced in patients with reduced left ventricular ejection fraction.

## Key findings

- Beta-blocker therapy was associated with reduced 1-year mortality in acute coronary syndrome patients.
- Patients with LVEF ≤ 40% had significantly lower mortality when on beta-blockers compared to those without.
- No mortality benefit was observed in patients with LVEF > 40%.

## Abstract

While the beneficial effect of beta-blocker (BB) therapy for acute coronary syndrome (ACS) patients with a left ventricular ejection fraction (LVEF) of 40% is established, its role in those with LVEF > 40% is controversial. We assessed the relationship between BB therapy at discharge and 1-year mortality according to LVEF in a large contemporary acute coronary syndrome (ACS) cohort.

Patients enrolled in the Acute Myocardial Infarction in Switzerland (AMIS) Plus registry between 2005 and 2024 with information on BB at discharge, LVEF, and 1-year mortality were studied. The association between BB therapy and 1-year mortality and the interaction with LVEF (>40% vs. ≤40%) were analysed. Among 7820 patients (65% with ST-segment elevation myocardial infarction), 1570 (20.1%) had LVEF ≤ 40%. At discharge, 6211/7820 (79.4%) patients were on BB (LVEF > 40%, 78.1%; LVEF ≤ 40%, 84.5%). One-year mortality was higher in patients with LVEF ≤ 40% vs. >40% (7.1% vs. 2.3%; P < 0.001). Overall, BB therapy was associated with reduced mortality [unadjusted odds ratio 0.67 (95% confidence interval 0.51–0.89); P = 0.005]. Among patients with LVEF ≤ 40%, mortality was lower in patients with BB compared with those without (5.9% vs. 14%; P < 0.001). In contrast, in patients with LVEF > 40%, mortality did not differ between patients with and without BB (2.1% vs. 2.6%; P = 0.3). A statistically significant interaction between BB therapy and LVEF stratum was identified (pinteraction = 0.02).

Data from our large, nationwide registry suggest an overall benefit of BB therapy at discharge on 1-year mortality in ACS with most of the survival advantage observed in patients with LVEF < 40%.

Graphical AbstractOR, odds ratio; PCI, percutaneous coronary intervention; 95% CI, 95% confidence interval.

OR, odds ratio; PCI, percutaneous coronary intervention; 95% CI, 95% confidence interval.