What is the treatment for stable ventricular tachycardia?

Treatment of Stable Ventricular Tachycardia

For patients with hemodynamically stable monomorphic ventricular tachycardia, procainamide (10 mg/kg IV) is the recommended first-line treatment in patients without severe congestive heart failure or acute myocardial infarction, while amiodarone is recommended for patients with or without severe heart failure or acute myocardial infarction. 1

Initial Assessment and Classification

When managing stable ventricular tachycardia (VT), it's crucial to:

1. Confirm hemodynamic stability (patient alert, blood pressure maintained)
2. Identify the VT morphology:
   • Monomorphic VT (uniform QRS complexes)
   • Polymorphic VT (varying QRS complexes)
3. Assess for underlying conditions:
   • Structural heart disease
   • Acute myocardial infarction
   • Severe heart failure
   • Electrolyte abnormalities
   • QT interval abnormalities

Treatment Algorithm for Stable Monomorphic VT

First-line pharmacological therapy:

• Without severe heart failure or acute MI:

  • Procainamide 10 mg/kg IV 1, 2

• With severe heart failure or acute MI:

  • Amiodarone 150 mg IV over 10 minutes, followed by 1 mg/min for 6 hours, then 0.5 mg/min 1, 3

If first-line therapy fails:

1. Synchronized electrical cardioversion (starting at 100 J) 1
2. Consider sotalol for patients with hemodynamically stable sustained monomorphic VT, including those with acute MI 1

Management of Polymorphic VT

Treatment depends on the underlying cause:

1. Polymorphic VT with long QT (Torsades de Pointes):

   • IV magnesium
   • Overdrive pacing
   • β-blockers for congenital long QT
   • Avoid isoproterenol in familial long QT 1

2. Polymorphic VT without long QT:

   • IV β-blockers (especially for ischemic VT)
   • Consider isoproterenol 1
   • Treat underlying ischemia if present 4

Special Considerations

• Correct electrolyte abnormalities: Maintain potassium >4.0 mEq/L and magnesium >2.0 mg/dL 4

• For recurrent episodes (VT storm):

  • High-dose β-blockers (propranolol more effective than metoprolol) 4
  • Consider combination of β-blockers with amiodarone 4
  • Urgent coronary revascularization if evidence of acute ischemia 4
  • Catheter ablation for incessant VT or storm rhythm resistant to medical treatment 4

• Adenosine: May be considered relatively safe in undifferentiated regular stable wide-complex tachycardia to help diagnose the underlying rhythm 1

Efficacy and Safety Considerations

• Procainamide: Effective for stable monomorphic VT without severe heart failure or acute MI, but has proarrhythmic effects and should be used with caution in patients with lesser arrhythmias 2

• Amiodarone: Effective in approximately 52% of stable VT cases 5, with long-term efficacy in about 69-71% of patients with refractory VT 6, 7

• Common side effects of amiodarone: Hypotension (slow the infusion), bradycardia, AV block, tremor/ataxia, nausea, visual disturbances, thyroid abnormalities, and pulmonary infiltrates 3, 6

Pitfalls to Avoid

1. Do not use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardias of unknown origin, as they can cause hemodynamic collapse if the rhythm is VT 1

2. Do not assume electrolyte abnormalities or antiarrhythmic drugs are the sole cause of VT - thorough evaluation is still required 4

3. Do not delay cardioversion if the patient becomes hemodynamically unstable during pharmacological treatment 1

4. Avoid isoproterenol in patients with polymorphic VT associated with familial long QT syndrome 1

5. Do not use amiodarone in patients with marked sinus bradycardia or second/third-degree AV block unless a functioning pacemaker is available 3