How do I lower heart rate (HR) for this patient?

Heart Rate Control in Atrial Fibrillation

Beta blockers are the first-line treatment for lowering heart rate in patients with atrial fibrillation, with metoprolol being an excellent choice at a dose of 25-100 mg twice daily orally. 1

First-Line Medications for Heart Rate Control

Beta Blockers

• Beta blockers are the most effective drug class for rate control, achieving heart rate endpoints in 70% of patients compared to 54% with calcium channel blockers 1
• For immediate rate control, intravenous beta blockers are recommended:
  • Metoprolol: 2.5-5.0 mg IV bolus over 2 minutes; up to 3 doses 1
  • Esmolol: 500 mcg/kg IV bolus over 1 minute, then 50-300 mcg/kg/min IV infusion 1, 2
• For long-term oral therapy:
  • Metoprolol tartrate: 25-100 mg twice daily 1
  • Metoprolol succinate (XL): 50-400 mg once daily 1
  • Carvedilol: 3.125-25 mg twice daily (also effective for reducing ventricular ectopy) 1

Nondihydropyridine Calcium Channel Antagonists

• Consider as alternative first-line agents, especially in patients with bronchospasm or COPD 1
• Diltiazem: 120-360 mg once daily (extended release) 1
• Verapamil: 180-480 mg once daily (extended release) 1
• These agents have been associated with improved quality of life and exercise tolerance 1
• Caution: Should not be used in patients with decompensated heart failure 1

Second-Line Options

Digoxin

• Consider in patients with heart failure or left ventricular dysfunction 1
• Dosing: 0.125-0.375 mg daily orally 1
• Limitations: Less effective during exercise or states of high sympathetic tone 1
• Not recommended as sole agent for rate control in paroxysmal AF 1

Amiodarone

• Consider when other measures are unsuccessful or contraindicated 1
• Oral dosing: 100-200 mg daily 1
• IV dosing (for critically ill patients): 300 mg IV over 1 hour, then 10-50 mg/hour 1
• Caution: Significant long-term toxicity concerns including pulmonary toxicity, thyroid dysfunction, and skin discoloration 1

Target Heart Rate Goals

• Strict rate control (resting heart rate <80 bpm) is reasonable for symptomatic management 1
• Lenient rate control (resting heart rate <110 bpm) may be reasonable in asymptomatic patients with preserved left ventricular function 1
• Heart rate should be assessed during both rest and exertion, with medication adjusted accordingly 1, 3

Special Considerations

Heart Failure

• Beta blockers should be initiated cautiously in patients with heart failure and reduced ejection fraction 1
• For acute rate control in heart failure patients, IV digoxin or amiodarone is recommended 1
• A combination of digoxin and a beta blocker is reasonable to control both resting and exercise heart rate 1

Pre-excitation Syndromes

• Avoid digoxin, nondihydropyridine calcium channel antagonists, and amiodarone in patients with AF and pre-excitation syndromes 1
• These medications may paradoxically accelerate ventricular response 1

Monitoring and Follow-up

• Assess heart rate control during both rest and exercise 1
• Monitor for bradycardia, heart block, and hypotension, especially in elderly patients 1
• For beta blockers, start at a low dose and titrate up gradually to avoid bradycardia and hypotension 1
• If one agent is insufficient, consider combination therapy (e.g., beta blocker plus digoxin) 1

When Pharmacological Management Fails

• AV nodal ablation with permanent ventricular pacing is reasonable when pharmacological management is inadequate and rhythm control is not achievable 1
• This should not be performed without prior attempts at medication management 1