What medications are used to manage ventricular fibrillation?

Management of Ventricular Fibrillation

Immediate defibrillation is the cornerstone of ventricular fibrillation management, with amiodarone being the most effective antiarrhythmic medication for refractory cases. 1

Initial Management Algorithm

1. Immediate Defibrillation

   • Unsynchronized electric shock using an initial energy of 200 J
   • If unsuccessful, deliver second shock at 200-300 J
   • If still unsuccessful, deliver third shock at 360 J 1

2. Pharmacological Management for Refractory VF

   • First-line antiarrhythmic: Intravenous amiodarone

     • Initial dose: 300 mg IV bolus (or 5 mg/kg)
     • Follow with infusion: 1 mg/min for 6 hours, then 0.5 mg/min 2
     • Amiodarone is superior for recurrent sustained VF requiring cardioversion 1, 3

   • Second-line antiarrhythmic: Lidocaine

     • Initial loading dose: 1-1.5 mg/kg IV
     • May follow with half this dose every 8-10 minutes to maximum of 4 mg/kg
     • Or continuous infusion of 1-4 mg/min (30-50 mcg/kg/min) 1

   • Adjunctive therapy: Epinephrine

     • 1 mg IV push, may repeat every 3-5 minutes 1

Special Considerations

• Beta-blockers (e.g., esmolol): Consider in cases of recurrent VF associated with acute myocardial infarction when other therapies fail 4

• Magnesium: Not routinely recommended for VF unless torsades de pointes is suspected 1

• Bretylium: No longer recommended for routine use in VF 3

• Electrolyte correction: Address any underlying hypokalaemia or other electrolyte disturbances 1

Post-Resuscitation Management

• After successful defibrillation, consider maintenance antiarrhythmic therapy for 6-24 hours, then reassess the need for continued treatment 1

• Identify and treat underlying causes:

  • Ongoing ischemia
  • Electrolyte abnormalities
  • Acid-base disturbances
  • Hypoxia
  • Altered autonomic tone 1

Common Pitfalls to Avoid

1. Delayed defibrillation: Immediate defibrillation is the most critical intervention for VF and should not be delayed for medication administration

2. Overuse of epinephrine: While commonly used, evidence suggests epinephrine may improve initial resuscitation rates but does not significantly improve survival to hospital discharge 5

3. Inappropriate medication use in pre-excitation: In patients with pre-excitation syndromes (WPW) and VF, avoid digoxin, non-dihydropyridine calcium channel blockers, and adenosine as they may worsen the arrhythmia 1

4. Failure to address underlying causes: VF is often a manifestation of serious underlying disorders that require immediate correction 1

The management of ventricular fibrillation requires prompt recognition and immediate intervention. While defibrillation remains the definitive treatment, amiodarone has emerged as the most effective pharmacological agent for refractory cases, with lidocaine serving as a reasonable alternative when amiodarone is unavailable or contraindicated.