Management of Ventricular Tachycardia
Immediate Assessment: Determine Hemodynamic Stability
The first and most critical step is to rapidly assess hemodynamic stability by checking for hypotension, altered mental status, chest pain, signs of shock, or heart failure—this single determination dictates your entire treatment pathway. 1
- Obtain a 12-lead ECG immediately to confirm VT and distinguish monomorphic from polymorphic patterns 1
- Establish IV access and ensure resuscitation equipment is readily available 2
- Assess oxygen saturation and provide supplemental oxygen if needed 2
Treatment Algorithm Based on Hemodynamic Status
Hemodynamically UNSTABLE VT: Immediate Electrical Therapy
For any patient showing signs of instability, proceed directly to synchronized cardioversion without delay—this is the definitive treatment and takes priority over all pharmacologic options. 3, 1
Monomorphic VT (Regular Form and Rate):
- Deliver synchronized cardioversion starting at 100 J using a biphasic defibrillator 3, 1
- If the first shock fails, escalate the dose in a stepwise fashion 3
- Provide immediate sedation if the patient is conscious, but do not delay cardioversion if the patient is extremely unstable 1
Polymorphic VT (Irregular):
- Use unsynchronized high-energy shocks (defibrillation doses of 200 J) as you would for ventricular fibrillation—do NOT use synchronized cardioversion 3, 1
- Polymorphic VT requires defibrillation because the device may not sense a consistent QRS wave for synchronization 3
Critical Pitfall:
- Never use synchronized cardioversion for polymorphic VT or pulseless VT—these require immediate defibrillation 3
Hemodynamically STABLE VT: Electrical or Pharmacologic Options
Even in stable patients, electrical cardioversion remains first-line therapy and is most efficacious, but pharmacologic options can be considered if cardioversion is not immediately available or if you need to prevent recurrence. 1, 4
Electrical Cardioversion:
- Synchronized cardioversion at 100 J (biphasic) is recommended when pharmacologic therapy fails or is contraindicated 3, 1
- This approach has the highest success rate for rhythm conversion 1
Pharmacologic Therapy:
For stable monomorphic VT, procainamide demonstrates the greatest efficacy and should be your first-line pharmacologic agent unless contraindicated. 1, 4
Procainamide: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 1, 4
Amiodarone: 150 mg IV over 10 minutes, followed by maintenance infusion 1, 5
- Preferred for patients with heart failure or suspected ischemia 1
- FDA-approved for frequently recurring VF and hemodynamically unstable VT refractory to other therapy 5
- Loading dose: approximately 1000 mg over first 24 hours, then maintenance infusion of 0.5 mg/min 5
- Must be delivered through a central venous catheter if concentration exceeds 2 mg/mL to avoid phlebitis 5
IV Beta-blockers (e.g., esmolol): Reasonable option with excellent safety profile, particularly if ischemia is suspected 1, 2
Key Pharmacologic Pitfall:
- Never administer calcium channel blockers (diltiazem, verapamil) for VT—these are for SVT only and can cause hemodynamic collapse or ventricular fibrillation in VT patients 3
Post-Cardioversion Management
After successful rhythm conversion, immediately focus on preventing recurrence and addressing underlying causes—VT will recur without this critical step. 1
- Start continuous cardiac monitoring for VT recurrence 1
- Obtain 12-lead ECG to assess for ST-segment elevation or ischemic changes 1
- Correct electrolyte abnormalities immediately, particularly potassium and magnesium 1, 2
- Start IV beta-blockers to prevent recurrent arrhythmias 1
- Check cardiac enzymes to assess for myocardial ischemia 2
Management of Recurrent or Refractory VT
For breakthrough episodes of VF or hemodynamically unstable VT despite initial treatment, administer supplemental amiodarone 150 mg IV over 10 minutes. 5
Electrical Storm (≥3 episodes in 24 hours):
- Urgent catheter ablation is indicated for scar-related heart disease with incessant VT or electrical storm despite optimal medical therapy 1
- Consider transvenous overdrive pacing if VT is frequently recurrent and catheter ablation is not immediately available 1
Special Considerations
Pulseless VT:
- Treat identically to ventricular fibrillation with immediate unsynchronized defibrillation 3
- Begin high-quality CPR immediately and minimize interruptions in chest compressions 3
Pediatric Dosing:
- Synchronized cardioversion: 0.5 to 1 J/kg initially, increase up to 2 J/kg if first shock fails 3
Non-Sustained VT (NSVT, <30 seconds):
- Monitor closely for recurrence or progression to sustained VT 2
- Correct electrolyte abnormalities and assess for myocardial ischemia 2
- Do not treat with antiarrhythmic drugs in asymptomatic patients without structural heart disease 2
- For patients with structural heart disease and reduced ejection fraction, obtain cardiology consultation for ICD evaluation 2
Critical Pitfalls to Avoid
- Never use Class IC antiarrhythmic drugs in patients with history of myocardial infarction 2
- Never use synchronized cardioversion for polymorphic VT—use defibrillation instead 3
- Never administer calcium channel blockers for VT 3
- Do not use drop counter infusion sets for amiodarone—use volumetric infusion pumps only to avoid underdosing by up to 30% 5
- Avoid amiodarone concentrations >2 mg/mL in peripheral veins due to high risk of phlebitis 5