Treatment of Ventricular Tachycardia (14 Beats)
For hemodynamically unstable VT, perform immediate synchronized DC cardioversion starting at 100J, escalating to 200J then 360J if needed; for stable monomorphic VT, procainamide is the preferred first-line pharmacological agent. 1, 2
Immediate Assessment: Determine Hemodynamic Stability
The critical first step is determining whether the patient is hemodynamically stable or unstable. 1, 3
Unstable VT is defined by:
- Systolic blood pressure ≤90 mmHg 1
- Chest pain or acute heart failure 1
- Altered mental status or syncope 3
- Heart rate ≥150 beats/min 1
Treatment Algorithm for Hemodynamically Unstable VT
Immediate synchronized cardioversion is the treatment of choice for unstable VT. 1, 3
- Start with 100J synchronized shock 1
- Escalate to 200J if unsuccessful 1
- Then 360J if still unsuccessful 1
- Sedate conscious but unstable patients immediately before cardioversion 1, 3
- If VT recurs after cardioversion, administer antiarrhythmic drugs (amiodarone 150 mg IV over 10 minutes) to prevent reinitiation 3, 4
Critical pitfall: Do not delay cardioversion in unstable patients—this is a Class I recommendation. 3
Treatment Algorithm for Hemodynamically Stable Monomorphic VT
First-Line Agent: Procainamide
Procainamide demonstrates the greatest efficacy among antiarrhythmics for stable monomorphic VT and is the preferred first-line agent. 1, 5, 2
Dosing protocol:
- 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 1, 5
- Maximum dose: 10-20 mg/kg 1
- Monitor continuously for hypotension and QRS widening during administration 1
Contraindications to procainamide:
Second-Line Agent: Amiodarone
When procainamide is contraindicated (heart failure or suspected ischemia), amiodarone is the preferred alternative. 1, 5, 4
Dosing protocol:
- 150 mg (5 mg/kg) IV over 10 minutes 1, 4
- Then 1 mg/min infusion for 6 hours 1
- Then 0.5 mg/min maintenance 1
- Amiodarone reduces life-threatening arrhythmias, required shocks, and symptomatic VT episodes 1, 5
Third-Line Agent: Sotalol
Sotalol may be considered for stable monomorphic VT, but exercise caution due to significant beta-sympatholytic properties. 1, 5
Special Considerations for Polymorphic VT
Normal QT Interval (Likely Ischemia-Related)
Prolonged QT Interval (Torsades de Pointes)
Administer IV magnesium sulfate immediately: 1
- 8 mmol bolus 1
- Followed by 2.5 mmol/h infusion 1
- Correct electrolyte abnormalities (potassium, magnesium) 1
Critical Pitfalls to Avoid
Never assume wide-complex tachycardia is supraventricular—when in doubt, treat as VT. 1
Avoid calcium channel blockers (verapamil, diltiazem) in VT with structural heart disease, as they may precipitate hemodynamic collapse and worsen outcomes. 1
Do not use prophylactic antiarrhythmic drugs other than beta-blockers, as they may be harmful. 3
Avoid adenosine for irregular or polymorphic wide-complex tachycardias. 3
Monitoring Requirements During Treatment
Continuous ECG monitoring is mandatory for all VT treatment. 1
- Measure and normalize serum potassium and magnesium before initiating antiarrhythmics 1
- Monitor QTc interval—discontinue drug if QTc prolongs to ≥500 ms 1
- Facility must have cardiac resuscitation capabilities immediately available 1
Long-Term Management After Acute Stabilization
After acute stabilization, evaluate for underlying causes including ischemia, electrolyte abnormalities, hypoxia, and acid-base disturbances. 3
- Beta-blockers are the cornerstone for catecholaminergic polymorphic VT 6, 5
- Consider ICD implantation for secondary prevention in structural heart disease 5
- Urgent catheter ablation is recommended for incessant VT or electrical storm in scar-related heart disease 5
- For idiopathic left VT (fascicular VT), catheter ablation by experienced operators is recommended as first-line treatment 6