From the Research
For atrial fibrillation with rapid ventricular response (RVR), metoprolol is the preferred beta blocker due to its cardioselectivity and established efficacy, with a typical initial dose of 5mg IV over 2-5 minutes, which can be repeated twice at 5-minute intervals (maximum 15mg), followed by oral dosing of 25-100mg twice daily 1.
Optimal Beta Blocker Dosage
The optimal dosage of metoprolol for atrial fibrillation with RVR is typically started at a low dose and titrated to achieve a heart rate less than 100 beats per minute, with careful monitoring for hypotension, bradycardia, and heart failure exacerbation.
- Metoprolol is often preferred due to its cardioselectivity and established efficacy, though the choice depends on patient-specific factors 2, 3.
- Esmolol, a shorter-acting option, is administered as a 500 mcg/kg IV loading dose over 1 minute, followed by a 50-200 mcg/kg/min infusion [@Example@].
Comparison of Beta Blockers
- A study comparing metoprolol and diltiazem for atrial fibrillation with RVR found that metoprolol had a lower failure rate than diltiazem and was superior in achieving rate control at 4 hours 4.
- Another study found that diltiazem reduced heart rate more quickly and reduced heart rate by 20% or greater more frequently than metoprolol, with no safety outcome differences 1.
Patient-Specific Factors
- Patients with concomitant heart failure with reduced ejection fraction (HFrEF) may require careful consideration of the choice of beta blocker, as diltiazem may have negative inotropic effects 5.
- Patients should be monitored for hypotension, bradycardia, and heart failure exacerbation, with dose adjustments made accordingly [@Example@].