In a hemodynamically stable patient with monomorphic ventricular tachycardia (blood pressure ≥90 mmHg, no chest pain, pulmonary edema, or altered mental status), should synchronized direct‑current cardioversion be used as the first‑line therapy?

Management of Hemodynamically Stable Monomorphic Ventricular Tachycardia

For hemodynamically stable monomorphic VT (blood pressure ≥90 mmHg, no chest pain, pulmonary edema, or altered mental status), synchronized direct-current cardioversion is the most effective first-line therapy and should be performed immediately with appropriate sedation. 1

Electrical Cardioversion as First-Line Therapy

Synchronized electrical cardioversion remains the definitive first-line treatment even in stable patients, as it demonstrates superior efficacy compared to all pharmacologic options. 1, 2

• Deliver an initial synchronized shock of 100 J for monomorphic VT with rates >150 bpm 3, 1
• If the first shock fails, escalate energy sequentially to 200 J, then 300 J, then 360 J 3
• Provide brief anesthesia or sedation when hemodynamically tolerable before cardioversion 3, 1
• Ensure proper synchronization to the R-wave peak to avoid delivering the shock on the T-wave 1

Pharmacologic Management When Cardioversion is Unavailable or Deferred

If electrical cardioversion is not immediately available or the clinical team chooses initial pharmacologic therapy, the following algorithm applies:

First-Line Antiarrhythmic Agent

Intravenous procainamide is the preferred first-line pharmacologic agent for stable monomorphic VT, demonstrating the greatest efficacy for rhythm conversion. 3, 1, 4

• Administer 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 1, 4
• Continuous blood pressure and ECG monitoring is mandatory during infusion due to risk of hypotension 1, 2
• Procainamide carries a Class IIa recommendation from the American Heart Association, superior to amiodarone's Class IIb recommendation 4
• Contraindication: Do not use procainamide in patients with severe heart failure or acute myocardial infarction 3

Alternative First-Line Agent in Specific Contexts

Intravenous amiodarone is preferred over procainamide only when the patient has heart failure, suspected myocardial ischemia, or left ventricular ejection fraction ≤40%. 3, 1

• Loading dose: 150 mg IV over 10 minutes, followed by maintenance infusion 1, 2
• Amiodarone has a slow onset of 20-30 minutes for its class III antiarrhythmic effect, making it suboptimal for early conversion 1
• It should be reserved for VT that is refractory to countershock or recurrent despite procainamide 1, 2

Second-Line Pharmacologic Options

• Sotalol may be considered for stable sustained monomorphic VT, including post-MI patients 3, 1
• Lidocaine provides only moderate efficacy and should be reserved as second-line when other agents are unsuitable 3, 1
• In the setting of acute myocardial ischemia, lidocaine (1 mg/kg bolus, then 0.5 mg/kg every 8-10 min) may be reasonable 1, 2

Critical Contraindications and Safety Pitfalls

Never administer calcium-channel blockers (verapamil, diltiazem) for wide-complex tachycardia unless you are absolutely certain it is fascicular VT, as they can precipitate ventricular fibrillation and hemodynamic collapse in structural heart disease. 3, 1, 2

• The only exception is confirmed left-ventricular fascicular VT (RBBB morphology with left axis deviation), where verapamil or β-blockers are safe and effective 1
• When the differential diagnosis between VT and supraventricular tachycardia with aberrancy is uncertain, always treat as VT to avoid the far greater risk of undertreatment 1

Management of Refractory or Recurrent VT

If VT persists after initial therapy or recurs after successful conversion:

• Proceed immediately to synchronized cardioversion if not already attempted 1, 2
• If cardioversion has already been performed, administer intravenous procainamide as second-line pharmacologic therapy after amiodarone failure 2
• For incessant VT or electrical storm, urgent catheter ablation should be considered 1, 5
• Beta-blockers are especially useful when ischemia is suspected and help reduce ventricular ectopy 1, 2
• Transvenous catheter pacing can terminate refractory VT but requires specialized equipment and expertise 2

Special Considerations for Ischemic VT

When acute myocardial ischemia is present or suspected:

• Urgent coronary angiography with revascularization should be pursued 1, 2
• Beta-blockers improve mortality in recurrent polymorphic VT with acute MI 1
• Correction of ischemia is an early priority for VT occurring during acute coronary syndrome 1

Reassessment of Hemodynamic Status

Continuously reassess hemodynamic stability; if the patient develops systolic BP <90 mmHg, pulmonary edema, altered mental status, or chest pain, proceed immediately to synchronized cardioversion regardless of prior pharmacologic attempts. 1, 2

Evidence Quality and Guideline Strength

The recommendation for cardioversion as first-line therapy is supported by Class I evidence from the European Society of Cardiology and American College of Cardiology 3, 1, 2. The superiority of procainamide over amiodarone for acute termination carries Class IIa versus Class IIb evidence respectively, though all pharmacologic studies suffer from small sample sizes and heterogeneous designs 4.