Are beta blockers (beta-adrenergic blocking agents) still the standard of care following myocardial infarction (MI)?

From the Guidelines

Beta blockers remain a crucial component of post-myocardial infarction (MI) care, particularly for patients with reduced left ventricular ejection fraction (LVEF ≤40%), where they are strongly recommended indefinitely 1. For these patients, beta blockers such as metoprolol succinate, carvedilol, or bisoprolol should be initiated at low doses and titrated upward as tolerated. The evidence supporting the use of beta blockers in patients with preserved LVEF is less robust, and their use in this group is more selective, often prescribed for 1-3 years post-MI. Key considerations in the management of post-MI patients include:

• The use of beta blockers without intrinsic sympathomimetic activity
• Selecting proven beta blockers such as carvedilol, sustained-release metoprolol succinate, or bisoprolol for patients with systolic cardiomyopathy or heart failure
• Avoiding beta blockers in patients with contraindications such as severe bradycardia, high-degree heart block, cardiogenic shock, or severe reactive airway disease
• Considering alternative or add-on therapies like ivabradine, nicorandil, or trimetazidine for patients with inadequate symptom control or specific clinical profiles. Recent guidelines and studies, including those from 2024 1, highlight the ongoing evolution of beta blocker use in post-MI care, emphasizing a more personalized approach based on individual patient characteristics and clinical presentation.

From the FDA Drug Label

In a large (1,395 patients randomized), double-blind, placebo-controlled clinical study, metoprolol was shown to reduce 3-month mortality by 36% in patients with suspected or definite myocardial infarction Treatment with Carvedilol Tablet may be started as an inpatient or outpatient and should be started after the patient is hemodynamically stable and fluid retention has been minimized.

• Beta blockers are still considered a standard of care following myocardial infarction (MI), as they have been shown to reduce mortality and improve outcomes in patients with MI 2.
• The use of beta blockers such as metoprolol and carvedilol is supported by clinical trials that demonstrate their effectiveness in reducing mortality and improving outcomes in patients with MI 2 3.
• Dosage and administration of beta blockers should be individualized and monitored during up-titration, with careful consideration of the patient's hemodynamic status and potential for orthostatic effects 3.

From the Research

Current Standard of Care for Myocardial Infarction (MI)

The use of beta blockers as the standard of care following myocardial infarction (MI) has been a topic of discussion in recent years.

• Studies have shown that the evidence supporting the use of beta blockers after MI is primarily derived from the pre-reperfusion era 4, 5.
• In the reperfusion era, the benefit of long-term beta-blocker therapy in patients post-MI without left ventricular dysfunction is uncertain 4, 6.

Benefits of Beta Blockers in Specific Patient Populations

• Beta blockers have been shown to reduce mortality after MI in patients with left ventricular dysfunction 7, 8.
• The CAPRICORN study demonstrated a significant mortality benefit when carvedilol was added to standard therapy in patients with left ventricular dysfunction after MI 7.
• A study comparing metoprolol and carvedilol after acute MI found that carvedilol may be superior in patients with left ventricular ejection fraction ≤40% 8.

Limitations of Current Evidence

• The majority of studies demonstrating the efficacy of beta blockers in post-MI patients were conducted in the pre-reperfusion era 4, 5.
• Recent analyses have shown that there is no convincing evidence for the use of beta blockers as first-line therapy in hypertension or in patients with stable coronary heart disease 5.
• A meta-analysis found that the use of oral beta blockers for 1 year or more does not reduce mortality in MI patients without heart failure 6.

Recommendations for Beta Blocker Use

• A rational recommendation for the modern treatment of MI would be to limit the use of beta blockers in the post-MI patient to higher-risk patients with evidence of ongoing ischemia, heart failure, or left ventricular dysfunction 5.
• The routine use of oral beta blockers in low-risk MI patients is not supported by current evidence 5.