What is the protocol for Amiodarone infusion in AFIB (Atrial Fibrillation) with RVR (Rapid Ventricular Response)?

Amiodarone Protocol for Atrial Fibrillation with Rapid Ventricular Response

For atrial fibrillation with rapid ventricular response, administer amiodarone with a loading dose of 150 mg IV over 10 minutes, followed by 1 mg/min for 6 hours, then 0.5 mg/min for the remainder of 24 hours (total 1000 mg over 24 hours), and continue with maintenance infusion at 0.5 mg/min (720 mg/day) thereafter. 1

Initial Management

Hemodynamic Assessment

• If patient is hemodynamically unstable (hypotension, ongoing ischemia, pulmonary edema, or shock): Perform immediate electrical cardioversion 2, 3
• If hemodynamically stable: Proceed with pharmacological rate control

Amiodarone Loading and Maintenance Protocol

1. First 24 Hours (Loading Phase) 1:

   • Initial bolus: 150 mg IV over 10 minutes
   • Follow with: 1 mg/min infusion for 6 hours (360 mg)
   • Then: 0.5 mg/min for 18 hours (540 mg)
   • Total first 24-hour dose: 1050 mg

2. Maintenance Phase 1:

   • Continue at 0.5 mg/min (720 mg per 24 hours)
   • Can be continued for 2-3 weeks if necessary
   • Use concentration of 1-6 mg/mL

3. For Breakthrough Episodes:

   • Administer supplemental 150 mg infusions over 10 minutes

Administration Guidelines

Important Administration Considerations

• Delivery method: Must use volumetric infusion pump 1
• Vascular access: Use central venous catheter for concentrations >2 mg/mL 1
• Solution preparation:
  • For infusions >2 hours: Use glass or polyolefin bottles containing D5W
  • Maximum concentration: 2 mg/mL for peripheral IV (to avoid phlebitis)
  • Use in-line filter during administration 1

Safety Precautions

• Do not exceed initial infusion rate of 30 mg/min 1
• Monitor for hypotension, especially with daily doses above 2100 mg 1
• High concentrations (>3 mg/mL) and rapid infusion rates have been associated with hepatocellular necrosis and acute renal failure 1
• Watch for peripheral vein phlebitis with concentrations >2.5 mg/mL 1

Monitoring During Infusion

• Continuous cardiac monitoring
• Blood pressure monitoring every 15 minutes during loading dose, then hourly
• Monitor for:
  • Hypotension (most common adverse effect)
  • Bradycardia
  • QT prolongation
  • Phlebitis at infusion site
  • Rare but serious: anaphylactic reactions 4

Efficacy and Expected Response

• Rate control typically begins within 1-2 hours 5
• Conversion to sinus rhythm may occur in 55-95% of patients within 24 hours 5
• Mean time to conversion is approximately 171 minutes in some studies 6
• Combination with digoxin may be more effective than amiodarone alone for maintaining sinus rhythm 7

Special Considerations

• Heart failure: Amiodarone is preferred over calcium channel blockers in patients with heart failure 2, 3
• Wolff-Parkinson-White syndrome: Amiodarone is contraindicated in pre-excited AF 2
• Hypertrophic cardiomyopathy: Amiodarone can be useful when combined with beta-blockers or calcium channel blockers 2
• Acute coronary syndrome: Amiodarone may be considered for AF with severe LV dysfunction and heart failure 2

Long-term Management

• After acute control, assess need for long-term rhythm control
• Consider transition to oral amiodarone if long-term therapy is indicated
• Evaluate for anticoagulation based on CHA₂DS₂-VASc score 3

Remember that amiodarone has considerable interindividual variation in response, so close monitoring with dose adjustment is essential 1. The protocol described above represents the standard approach, but clinical judgment may necessitate adjustments based on individual patient response.