What is the management approach for ventricular tachycardia (VT)?

Management Approach for Ventricular Tachycardia

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

Classification of VT

VT can be classified based on several characteristics:

• Morphology:

  • Monomorphic VT: Consistent QRS morphology 1
  • Polymorphic VT: Continually changing QRS morphology, often associated with acute myocardial ischemia, channelopathies, or ventricular hypertrophy 1

• Hemodynamic status:

  • Stable VT: Patient maintains adequate blood pressure and consciousness 1
  • Unstable VT: Associated with hypotension, altered mental status, or signs of shock 1

• Duration:

  • Sustained VT: Lasting >30 seconds or requiring intervention due to hemodynamic compromise 1
  • Non-sustained VT: Self-terminating within 30 seconds 1

Initial Assessment

• Any wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear 1
• A 12-lead ECG should be recorded for all patients with sustained VT who present in a hemodynamically stable condition 1
• Diagnostic clues for VT include:
  • RS interval >100 ms in any precordial lead 1
  • Negative concordance in precordial leads 1
  • Presence of fusion beats 1
  • QR complexes (indicating myocardial scar) 1

Management Algorithm

1. Hemodynamically Unstable VT

• Immediate synchronized cardioversion with appropriate sedation if the patient is conscious 1
• After cardioversion:
  • Start antiarrhythmic medication to prevent recurrence 1
  • Intravenous amiodarone is recommended (loading dose of 150 mg over 10 minutes, followed by infusion of 1 mg/min for 6 hours, then 0.5 mg/min) 2

2. Hemodynamically Stable Monomorphic VT

• First-line approach: Direct current cardioversion with appropriate sedation 1

• If medical management is chosen:

  • First choice: Intravenous procainamide (reasonable for initial treatment) at 20-30 mg/min up to 10 mg/kg 1, 3
  • Second choice: Intravenous amiodarone for VT that is refractory to conversion with countershock or recurrent despite procainamide 1
  • For VT associated with acute myocardial ischemia: Intravenous lidocaine might be reasonable 1

• Important caution: Calcium channel blockers (verapamil, diltiazem) should NOT be used to terminate wide-QRS-complex tachycardia of unknown origin, especially in patients with myocardial dysfunction 1

3. Polymorphic VT

• First-line: Direct current cardioversion for hemodynamically unstable patients 1
• For recurrent polymorphic VT:
  • Intravenous beta-blockers, especially if ischemia is suspected 1
  • Intravenous amiodarone loading in the absence of abnormal repolarization related to long QT syndrome 1
  • Urgent angiography with revascularization when myocardial ischemia cannot be excluded 1

4. Post-Conversion Management

• Correction of potentially causative or aggravating conditions:

  • Electrolyte abnormalities (particularly hypokalemia) 1
  • Myocardial ischemia 1
  • Drug toxicity 1

• For recurrent or incessant VT:

  • Urgent catheter ablation is recommended in patients with scar-related heart disease 1
  • Catheter ablation is recommended in patients with ischemic heart disease and recurrent ICD shocks due to sustained VT 1
  • Catheter ablation should be considered after a first episode of sustained VT in patients with ischemic heart disease and an ICD 1

Long-term Management Considerations

• Implantable cardioverter-defibrillator (ICD) placement for patients with structural heart disease and sustained VT 4
• Radiofrequency catheter ablation for patients with sustained VT and structurally normal heart (idiopathic VT) 4
• Antiarrhythmic medications for long-term suppression based on underlying cardiac substrate 4
• Coronary revascularization if VT is associated with ischemic heart disease 1

Common Pitfalls and Caveats

• Misdiagnosis of wide-complex tachycardias is common; when in doubt, treat as VT 1
• Adenosine should be used with caution in wide-complex tachycardias of unknown origin as it may precipitate ventricular fibrillation in patients with coronary artery disease 1
• Intravenous amiodarone concentrations >3 mg/mL have been associated with peripheral vein phlebitis; for infusions >1 hour, do not exceed 2 mg/mL unless using a central venous catheter 2
• Mortality is significantly higher when VT occurs during acute myocardial infarction (65% of unstable VT patients have acute MI compared to 21% of stable VT patients) 5
• Even in patients who initially present as hemodynamically stable, approximately 50% may eventually require electrical therapy for definitive termination 5