From the Guidelines
Yes, beta blockers are recommended post myocardial infarction in patients with an ejection fraction of 50 percent or greater according to ACC guidelines.
Recommendation
The most recent and highest quality study, 1, recommends that beta-blocker therapy should be started and continued for 3 years in all patients with normal LV function who have had MI or ACS.
Key Points
- Beta blockers should be initiated within the first 24 hours after a myocardial infarction if there are no contraindications, and continued indefinitely.
- Common beta blockers used in this setting include metoprolol (starting at 25-50 mg twice daily and titrating up), carvedilol (starting at 3.125-6.25 mg twice daily), and bisoprolol (starting at 1.25-2.5 mg daily).
- These medications should be started at low doses and gradually increased to target doses as tolerated.
- Beta blockers work by blocking the effects of adrenaline on beta-adrenergic receptors, reducing heart rate, blood pressure, and myocardial oxygen demand.
- Contraindications include severe bradycardia, high-degree heart block, cardiogenic shock, and severe bronchospastic disease.
- Patients should be monitored for potential side effects such as fatigue, dizziness, bradycardia, and hypotension.
Rationale
The use of beta blockers in patients with an ejection fraction of 50 percent or greater post myocardial infarction is supported by the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery, 1.
Considerations
- The guideline recommends that beta-blocker therapy should be used in all patients with LV systolic dysfunction (EF ≤40%) with HF or prior MI, unless contraindicated, as stated in 1.
- It is also reasonable to continue beta blockers >3 years as chronic therapy in all patients with normal LV function who have had MI or ACS, as stated in 1.
From the Research
Beta Blockers Post MI in Patients with LVEF of 50% or Greater
- The use of beta blockers in patients with a left ventricular ejection fraction (LVEF) of 50% or greater after myocardial infarction (MI) has been studied in several trials 2, 3.
- A study published in The New England Journal of Medicine in 2024 found that long-term beta-blocker treatment did not lead to a lower risk of death from any cause or new myocardial infarction in patients with acute MI and preserved LVEF (≥50%) 2.
- Another study published in Current Cardiology Reviews in 2012 noted that there is no clear recommendation regarding the appropriate duration of treatment with beta blockers in post-MI patients with normal LVEF who are not experiencing angina, or who require beta blockers for hypertension or dysrhythmia 3.
- The American Heart Association/American College of Cardiology guidelines recommend the use of beta blockers in patients post-MI, but the intensity of treatment is guided by the degree of LV dysfunction and the presence or absence of ischemia and arrhythmic risk markers 4.
Key Findings
- A study comparing metoprolol and carvedilol in patients with acute MI found that overall survival was similar for patients treated with metoprolol or carvedilol, but may be superior for carvedilol in patients with LVEF ≤40% 5.
- The use of low doses of metoprolol, bisoprolol, and carvedilol in patients with postinfarction left ventricular dysfunction (EF ≤35%) did not reduce mortality rate in 24-month observation 6.
- The latest ACC/AHA guidelines recommend beta blockers for early use in the setting of AMI, except in patients who are at low risk, and then indefinitely as secondary prevention after AMI 3.