How should a hemodynamically stable ventricular tachycardia be acutely managed in a conscious patient with adequate blood pressure and no signs of acute heart failure or shock?

Management of Hemodynamically Stable Ventricular Tachycardia

For a conscious patient with stable VT and adequate blood pressure, intravenous procainamide is the preferred first-line pharmacological agent (10 mg/kg IV at 50-100 mg/min over 10-20 minutes), though electrical cardioversion remains the most efficacious option and should be readily available. 1, 2

Initial Assessment and Diagnostic Confirmation

Obtain a 12-lead ECG immediately to confirm the diagnosis and characterize the VT morphology (monomorphic vs polymorphic). 3, 1 Key diagnostic features supporting VT include:

• QRS width >0.14 seconds with RBBB pattern or >0.16 seconds with LBBB pattern 1
• AV dissociation, fusion beats, or capture beats 1
• RS interval >100 ms in any precordial lead 1
• QR complexes indicating myocardial scar (present in ~40% of post-MI VT) 1

When the diagnosis is uncertain between VT and supraventricular tachycardia with aberrancy, always treat as VT — this is the safer approach as calcium channel blockers or adenosine given for presumed SVT can cause hemodynamic collapse in true VT. 1, 4

Treatment Algorithm for Stable Monomorphic VT

First-Line Pharmacological Management

Intravenous procainamide demonstrates the greatest efficacy for rhythm conversion and is recommended as the preferred agent for stable monomorphic VT when early termination is desired. 1, 2

• Dosing: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 1, 2
• Monitoring: Close blood pressure and continuous ECG monitoring required 1
• Contraindications: Avoid in patients with severe heart failure or acute myocardial infarction 1

Alternative Pharmacological Options

Intravenous amiodarone is preferred over procainamide in specific clinical contexts: 1, 4

• Patients with heart failure 3, 1
• Suspected myocardial ischemia 3, 1
• Impaired left ventricular function 1
• Dosing: 150 mg IV over 10 minutes, followed by maintenance infusion 1

Intravenous sotalol may be considered for hemodynamically stable sustained monomorphic VT, including post-MI patients. 1

Intravenous lidocaine is only moderately effective and should be considered second-line therapy. 3, 1, 4

Electrical Cardioversion

Synchronized electrical cardioversion is the most efficacious treatment and should be the first-line approach even in stable patients. 3, 1 When pharmacological therapy fails or is contraindicated, proceed directly to synchronized cardioversion. 3, 1

• For monomorphic VT: 100 J synchronized discharge for rates >150 bpm 1
• For polymorphic VT resembling VF: Unsynchronized 200 J discharge 1

Special Considerations and Critical Pitfalls

Specific VT Subtypes Requiring Different Management

Left ventricular fascicular VT (characterized by RBBB morphology with left axis deviation) responds to intravenous verapamil or beta-blockers rather than standard VT therapy. 3

Polymorphic VT requires different management: 1

• Direct current cardioversion for hemodynamically compromised patients 1
• Intravenous beta-blockers for recurrent episodes, especially if ischemia suspected 1
• Urgent revascularization when ischemia cannot be excluded 1

Medications to Absolutely Avoid

Never administer calcium channel blockers (verapamil or diltiazem) to patients with VT and structural heart disease — this can precipitate ventricular fibrillation and hemodynamic collapse. 3, 1, 4 The only exception is confirmed fascicular VT. 3, 1

Post-Conversion Management

After successful termination, address the following priorities:

• Correct underlying causes: Evaluate for ongoing myocardial ischemia, electrolyte abnormalities (especially potassium), hypoxia, and acid-base disturbances 4
• Initiate beta-blocker therapy at maximal tolerated doses (reduces recurrent VT/VF by 52%, HR 0.48) 4
• Consider adding amiodarone for VT prevention (combination with beta-blocker reduces ICD shocks by 73%, HR 0.27) 4
• Maintain continuous ECG monitoring for at least 3 days 4

When to Consider Urgent Catheter Ablation

Urgent catheter ablation is recommended for: 3, 1, 4

• Incessant VT or electrical storm in patients with scar-related heart disease 3, 1
• Recurrent ICD shocks due to sustained VT 1, 4
• Consider after first episode of sustained VT in patients with ischemic heart disease and an ICD 1, 4

Key Clinical Pearls

Hemodynamic stability can be deceptive — approximately half of patients presenting with stable VT ultimately require electrical cardioversion during their course. 5 Therefore, direct current cardioversion capability must be immediately available even when attempting pharmacological management. 5

VT occurring during acute myocardial infarction carries significantly higher mortality and more frequently requires electrical therapy. 5 In this context, prioritize revascularization and beta-blockade alongside antiarrhythmic therapy. 1