What are the first line drugs for a patient with stable ventricular tachycardia (VT)?

First-Line Drugs for Stable Ventricular Tachycardia

For hemodynamically stable monomorphic VT, procainamide is the recommended first-line agent when the patient does not have severe heart failure or acute MI, while amiodarone is preferred for patients with or without these comorbidities. 1

Treatment Algorithm Based on Patient Characteristics

For Patients WITHOUT Severe Heart Failure or Acute MI

• Procainamide is the first-line drug, administered as 20-30 mg/min IV up to a maximum of 10-17 mg/kg (approximately 12 mg/kg), followed by maintenance infusion of 1-4 mg/min 1
• Procainamide demonstrates superior efficacy compared to other agents for terminating stable monomorphic VT, with the highest conversion rates among medical options 1, 2
• Critical monitoring requirement: Close blood pressure monitoring is essential, and infusion rates must be reduced in patients with renal dysfunction 1, 3
• Stop the infusion if hypotension develops or QRS widens by >50% 1

For Patients WITH Severe Heart Failure or Acute MI

• Amiodarone is the first-line drug for these patients, administered as 150 mg IV over 10 minutes, followed by maintenance infusion of 1.0 mg/min for 6 hours, then 0.5 mg/min 1, 3, 4
• Amiodarone is recommended for hemodynamically stable monomorphic VT with or without severe congestive heart failure or acute MI 1
• Combining amiodarone with IV beta-blockers enhances efficacy and should be considered for optimal outcomes 3, 4

Alternative Second-Line Agents

• Lidocaine may be considered specifically when VT is thought to be related to acute myocardial ischemia, administered as 1.0-1.5 mg/kg IV bolus, with supplemental boluses of 0.5-0.75 mg/kg every 5-10 minutes to a maximum of 3 mg/kg total loading dose, followed by infusion of 2-4 mg/min 1, 3, 4
• However, lidocaine is relegated to second-line status and is not as effective as procainamide for early conversion 1
• Sotalol may be considered for hemodynamically stable sustained monomorphic VT, including patients with acute MI 1

Critical Pitfalls to Avoid

• Never use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardia of unknown origin, especially in patients with myocardial dysfunction—this can precipitate ventricular fibrillation or profound hypotension 1, 4
• Avoid Class IC antiarrhythmics (flecainide, propafenone) in patients with prior MI or acute coronary syndrome 3
• Do not administer adenosine for confirmed VT, though it may be considered relatively safe for undifferentiated regular stable wide-complex tachycardia to aid diagnosis 1

Essential Pre-Treatment Steps

• Correct electrolyte abnormalities immediately, particularly hypokalemia and hypomagnesemia, as these are potentially causative or aggravating conditions 1, 4
• Keep cardioversion equipment immediately available when administering any antiarrhythmic agent 4
• Always follow IV drugs with 20 mL saline bolus to aid delivery to central circulation 4

When Medical Management Fails

• Direct current cardioversion remains the most efficacious treatment and should be performed at any point if the patient becomes hemodynamically unstable or if pharmacological therapy fails 1, 2
• Synchronized cardioversion with appropriate sedation is recommended if medical management is unsuccessful 1