What is the treatment for sustained ventricular (V) tachycardia?

Treatment of Sustained Ventricular Tachycardia

Direct current cardioversion is the first-line treatment for patients presenting with sustained ventricular tachycardia (VT) and hemodynamic instability. 1

Initial Assessment and Classification

• Assess hemodynamic stability first by evaluating blood pressure, mental status, and signs of hypoperfusion 2
• Obtain a 12-lead ECG for all patients with sustained VT who present in a hemodynamically stable condition 1
• Classify VT as monomorphic (consistent QRS morphology) or polymorphic (changing QRS morphology) 3
• Any wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear 1

Treatment Algorithm Based on Hemodynamic Status

For Hemodynamically Unstable Patients

• Perform immediate synchronized cardioversion with appropriate sedation 1, 3
• Start with 100-200 J for synchronized cardioversion 2
• Have resuscitation equipment readily available 2

For Hemodynamically Stable Patients with Monomorphic VT

1. Direct current cardioversion with appropriate sedation is still the recommended first-line approach 1
2. If medication is preferred before cardioversion:
   • Intravenous procainamide is the first choice (20-30 mg/min up to 10 mg/kg) 1, 3, 4
   • Intravenous amiodarone (150 mg over 10 minutes, followed by infusion) for patients with heart failure or when procainamide is unavailable 1, 5
   • Intravenous lidocaine might be reasonable only if VT is specifically associated with acute myocardial ischemia 1

For Polymorphic VT

• Direct current cardioversion for hemodynamically unstable patients 1, 3
• Intravenous beta-blockers are useful, especially if ischemia is suspected 1
• Intravenous amiodarone loading in the absence of abnormal repolarization related to long QT syndrome 1
• Urgent angiography with a view to revascularization should be considered when myocardial ischemia cannot be excluded 1

Medication Administration Details

Amiodarone

• Loading dose: 150 mg over 10 minutes 5
• Follow with 1 mg/min for 6 hours (360 mg) 5
• Then 0.5 mg/min maintenance infusion (720 mg/24 hours) 5
• For breakthrough episodes, give 150 mg supplemental infusions over 10 minutes 5
• FDA approved for hemodynamically unstable VT refractory to other therapy 5

Procainamide

• Administer at 20-30 mg/min up to a maximum dose of 10 mg/kg 3, 4
• Monitor blood pressure and ECG during administration 1
• Avoid in patients with significant QT prolongation or heart failure 1

Post-Conversion Management

• Evaluate for underlying causes of VT, including:
  • Myocardial ischemia (check cardiac enzymes) 1, 2
  • Electrolyte abnormalities (particularly potassium and magnesium) 2
  • Structural heart disease 1
• Consider maintenance antiarrhythmic therapy to prevent recurrence 1
• Cardiology consultation is recommended, particularly for patients with structural heart disease 2

Long-term Management Considerations

• Coronary revascularization if VT is associated with ischemic heart disease 3
• Consider implantable cardioverter-defibrillator (ICD) for patients with structural heart disease and sustained VT 1, 6
• Electrophysiology consultation for risk stratification in patients with recurrent episodes 2

Common Pitfalls to Avoid

• Avoid calcium channel blockers such as verapamil and diltiazem for wide-QRS-complex tachycardia of unknown origin 1
• Don't delay cardioversion in hemodynamically unstable patients 1
• Avoid class IC antiarrhythmic drugs in patients with history of myocardial infarction 2
• Don't underestimate the seriousness of "stable" VT - mortality in patients with stable VT can be high (33.6% at 3 years) 6

Special Considerations

• For VT associated with acute myocardial infarction, beta-blockers improve mortality 1
• For torsades de pointes, withdraw offending drugs, correct electrolyte abnormalities, and consider magnesium sulfate 1
• In pediatric patients, IV verapamil should be avoided in infants <1 year of age as it may lead to acute hemodynamic deterioration 1