Treatment for Ventricular Tachycardia
For hemodynamically unstable VT (hypotension with systolic BP ≤90 mmHg, altered mental status, signs of shock, chest pain, or acute heart failure), perform immediate synchronized cardioversion starting at 100J, escalating to 200J then 360J if needed. 1, 2, 3
Immediate Assessment: Stable vs. Unstable
Determine hemodynamic stability first—this dictates your entire treatment pathway. 2, 3
Unstable VT requires immediate cardioversion:
- Hypotension (systolic BP ≤90 mmHg) 2
- Altered mental status or loss of consciousness 3, 4
- Signs of shock 1, 3
- Chest pain or acute heart failure 2
- Heart rate ≥150 beats/min 2
If the patient is hypotensive but conscious, give immediate sedation before cardioversion. 1, 3
For pulseless VT, follow the VF protocol with immediate unsynchronized defibrillation at 200J. 2
Treatment Algorithm for Hemodynamically Stable Monomorphic VT
First-Line Pharmacological Treatment
Procainamide is the preferred first-line agent for stable monomorphic VT, demonstrating the greatest efficacy among antiarrhythmics. 1, 2, 3, 5
Dosing: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes (maximum dose 10-20 mg/kg) 1, 2, 5
Monitor continuously for hypotension and QRS widening during administration. 2
Critical Exception—When NOT to Use Procainamide:
Avoid procainamide in patients with severe heart failure or acute myocardial infarction—use amiodarone instead. 2, 3
Second-Line: Amiodarone
Amiodarone is preferred in patients with heart failure, suspected ischemia, or impaired left ventricular function. 1, 3, 6
Dosing: 150 mg (5 mg/kg) IV over 10 minutes, then 1 mg/min infusion for 6 hours, then 0.5 mg/min 1, 6
Amiodarone reduces life-threatening arrhythmias, required shocks, and symptomatic VT episodes. 1, 2
Third-Line: Sotalol
Sotalol may be considered for stable monomorphic VT, including patients with acute myocardial infarction, but exercise caution due to significant beta-sympatholytic properties. 1, 7
Critical monitoring requirement: Do not initiate if baseline QTc >450 ms; discontinue if QTc prolongs to ≥500 ms 7
Lidocaine: Less Effective
Intravenous lidocaine is only moderately effective in VT and less effective than procainamide, sotalol, or amiodarone—consider it second-line only. 1, 3
Treatment Algorithm for Polymorphic VT
With Normal QT Interval (Likely Ischemia-Related):
- Consider IV beta-blockers and treat underlying ischemia aggressively 3
- IV amiodarone loading is useful for recurrent polymorphic VT in the absence of QT prolongation 3
- Urgent revascularization should be considered when ischemia cannot be excluded 3
With Prolonged QT (Torsades de Pointes):
- Administer IV magnesium sulfate: 8 mmol bolus followed by 2.5 mmol/h infusion 2, 3
- Correct electrolyte abnormalities (potassium, magnesium) 2
- Consider overdrive pacing (atrial or ventricular) 3
Polymorphic VT Appearing Similar to VF:
- Use unsynchronized discharge of 200J 3
When Pharmacological Therapy Fails
If VT recurs after cardioversion, administer antiarrhythmic drugs to prevent acute reinitiation. 3
When pharmacological therapy is ineffective or contraindicated, proceed to synchronized cardioversion. 8, 3
Critical Pitfalls to Avoid
Never assume a wide-complex tachycardia is supraventricular—when in doubt, treat as VT. 2, 3
Avoid calcium channel blockers (verapamil, diltiazem) in VT with structural heart disease, as they may precipitate hemodynamic collapse and worsen outcomes. 2, 3
Wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear. 3
Mandatory Monitoring Requirements
Continuous ECG monitoring is mandatory for all VT treatment. 2
Measure and normalize serum potassium and magnesium before initiating antiarrhythmics. 2, 7
Monitor QTc interval—discontinue drug if QTc prolongs to ≥500 ms. 2, 7
Facility must have cardiac resuscitation capabilities immediately available. 2, 7
Long-Term Management Considerations
Urgent catheter ablation is recommended for incessant VT or electrical storm in scar-related heart disease. 1, 3
Catheter ablation is recommended in patients with ischemic heart disease and recurrent ICD shocks due to sustained VT. 1
Beta-blockers are the cornerstone of treatment for catecholaminergic polymorphic VT. 1, 2
Consider ICD implantation for secondary prevention in structural heart disease—even "stable" VT carries high mortality risk (33.6% at 3 years). 9