What is the initial recommended medication for sustained ventricular (VT) tachycardia?

Initial Medication Management for Sustained Ventricular Tachycardia

For sustained ventricular tachycardia, intravenous amiodarone is the recommended initial medication, particularly for hemodynamically stable monomorphic VT with or without severe congestive heart failure or acute myocardial infarction. 1

Treatment Algorithm Based on Hemodynamic Status

Hemodynamically Unstable VT

1. Immediate electrical cardioversion/defibrillation is the first-line intervention 2

   • For monomorphic VT: Synchronized cardioversion starting at 100-150J (biphasic) or 200J (monophasic)
   • For polymorphic VT: Unsynchronized defibrillation starting at 200J

2. After cardioversion, initiate IV amiodarone:

   • Loading dose: 150mg IV over 10 minutes 3
   • Followed by: 1mg/min for 6 hours
   • Then: 0.5mg/min for maintenance 3

Hemodynamically Stable VT

Monomorphic VT

1. First-line medication options:

   • Amiodarone: 150mg IV over 10 minutes, followed by infusion 1, 2
   • Procainamide: 10mg/kg IV (if no severe CHF or acute MI) 1

2. Decision factors for choosing between amiodarone and procainamide:

   • Choose amiodarone if: Patient has CHF, acute MI, or reduced ejection fraction 1
   • Choose procainamide if: Normal cardiac function without CHF or acute MI 1

Polymorphic VT

1. For torsades de pointes (polymorphic VT with long QT):

   • IV magnesium sulfate: 2g over 10 minutes 2
   • Correct electrolyte abnormalities
   • Consider temporary pacing if pause-dependent

2. For polymorphic VT without long QT:

   • IV beta-blockers (especially if ischemia suspected) 2
   • IV amiodarone as above 2
   • Consider urgent coronary angiography if ischemia cannot be excluded 2

Amiodarone Dosing Protocol

1. Initial loading:

   • 150mg IV over 10 minutes 3
   • For breakthrough episodes, repeat the 150mg bolus 3

2. Maintenance infusion:

   • 1mg/min for 6 hours (360mg) 3
   • Then 0.5mg/min (720mg/24 hours) 3
   • Total first 24-hour dose: approximately 1000mg 3

3. Administration considerations:

   • Use volumetric infusion pump 3
   • For concentrations >2mg/mL, use central venous access 3
   • Monitor for hypotension during administration 3

Important Cautions and Contraindications

1. Do not use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardias of unknown origin 2

2. Avoid adenosine in irregular or polymorphic wide-complex tachycardias 2

3. Monitor for amiodarone adverse effects:

   • Hypotension (most common acute adverse effect) 3
   • Bradycardia and AV block 3
   • QT prolongation 1

4. Contraindications to amiodarone:

   • Known hypersensitivity to amiodarone or iodine 3
   • Cardiogenic shock 3
   • Marked sinus bradycardia 3
   • Second- or third-degree AV block without functioning pacemaker 3

Long-term Management Considerations

After acute stabilization with IV amiodarone:

1. Evaluate for underlying structural heart disease
2. Consider electrophysiology study and catheter ablation
3. Evaluate for ICD placement in high-risk patients
4. Transition to oral amiodarone (typically 800-1600mg/day initially, then 200-400mg/day maintenance) 1

Amiodarone has demonstrated high efficacy (65-87%) in controlling recurrent ventricular tachycardia in multiple studies 4, 5, 6, making it the preferred agent for sustained VT, particularly when other antiarrhythmic drugs have failed.