Induction Medications for Cardioversion
For Atrial Fibrillation/Flutter
For hemodynamically unstable patients with AF/flutter, immediate synchronized electrical cardioversion is the treatment of choice, preceded by brief general anesthesia or conscious sedation with intravenous midazolam and/or propofol 1, 2. This takes priority over any pharmacological approach when patients present with hypotension, ongoing ischemia, heart failure, or severe symptoms.
Pharmacological Cardioversion Options
For hemodynamically stable patients requiring chemical cardioversion:
First-line agents (patients WITHOUT structural heart disease):
- Flecainide: 200-300 mg oral or 1.5-2 mg/kg IV over 10 minutes 2, 3
- Propafenone: 450-600 mg oral or 1.5-2 mg/kg IV over 10 minutes 2, 3
- Vernakalant: 3 mg/kg IV over 10 minutes, may repeat 2 mg/kg after 15 minutes 2, 3
These agents are contraindicated in patients with ischemic heart disease, significant structural heart disease, severe left ventricular hypertrophy, or heart failure with reduced ejection fraction.
For patients WITH structural heart disease, heart failure, or coronary artery disease:
- Amiodarone: 5-7 mg/kg (typically 150 mg) IV over 10 minutes, may repeat, followed by 1 mg/min infusion for 6 hours, then 0.5 mg/min 4, 2, 3
- Note: Conversion is delayed (8-12 hours), but this is the safest option in compromised patients
- Alternative oral loading: 30 mg/kg single dose or 600-800 mg daily until 10g total 5
Alternative agents:
Ibutilide: 1 mg IV over 10 minutes, may repeat once after 10 minutes 2, 6
Procainamide: 20-50 mg/min until arrhythmia suppressed, hypotension, or QRS prolonged by 50%, maximum 17 mg/kg 4
- Avoid in QT prolongation and heart failure
Critical Safety Considerations
Avoid these drugs in specific scenarios:
- Digoxin and sotalol should NOT be used for acute cardioversion of AF 9
- In pre-excited AF (WPW), avoid AV nodal blocking agents (digoxin, diltiazem, verapamil, amiodarone); use procainamide or ibutilide instead, or immediate cardioversion if unstable 4, 10
- Beta-blockers, diltiazem, and verapamil are for rate control, not rhythm conversion
For Ventricular Tachycardia
For hemodynamically unstable VT, immediate synchronized cardioversion is mandatory 4, 11. Follow ACLS protocols.
For Stable Monomorphic VT:
First-line options:
- Procainamide: 20-50 mg/min until arrhythmia suppressed, hypotension, or QRS prolonged by 50%, maximum 17 mg/kg 4
- Amiodarone: 150 mg IV over 10 minutes, may repeat, followed by 1 mg/min × 6 hours, then 0.5 mg/min 4
- Lidocaine: 1-1.5 mg/kg IV, may repeat 0.5-0.75 mg/kg every 5-10 minutes to maximum 3 mg/kg 4
Sotalol (1.5 mg/kg over 5 minutes) is an alternative but avoid in QT prolongation and heart failure 4.
For Polymorphic VT:
- Normal QT interval: Amiodarone 150 mg IV or lidocaine 100 mg IV 11
- Prolonged QT (Torsades de Pointes):
- Magnesium sulfate: 1-2 g IV over 15 minutes 4
- Remove precipitants, correct electrolytes
- Consider overdrive pacing
- Non-selective beta-blocker (propranolol preferred)
For Electrical Storm (≥3 episodes in 24 hours):
Immediate management:
- Non-selective beta-blocker (propranolol preferred over metoprolol) 11
- IV amiodarone 11
- Consider sedation/general anesthesia
- Involve electrophysiology early
Sedation for Electrical Cardioversion
Standard approach: IV midazolam and/or propofol with continuous blood pressure and oxygen saturation monitoring 2. Have atropine, isoproterenol, or temporary pacing available for post-cardioversion bradycardia 2.
For electrical storm with recurrent VT/VF, dexmedetomidine and propofol are preferred sedating agents 11.