What is the best treatment approach for a patient presenting with ventricular tachycardia (Vtach), considering their medical history and potential hemodynamic stability?

Management of Ventricular Tachycardia

For hemodynamically unstable VT (hypotension, altered mental status, shock), perform immediate synchronized direct current cardioversion without delay—sedation first only if the patient is conscious. 1, 2

Initial Assessment: Determine Hemodynamic Stability

The critical first step is rapid assessment of hemodynamic status, which dictates your entire treatment pathway 2, 3:

• Unstable indicators: Hypotension, altered mental status, signs of shock, chest pain, heart failure, or heart rate ≥150 bpm 1, 3
• Stable: Patient conscious, adequate perfusion, tolerating the rhythm 1, 2

When uncertain whether a wide-complex tachycardia is VT versus SVT with aberrancy, always treat as VT—this is the safer approach. 2, 3

Hemodynamically Unstable VT

Proceed directly to synchronized cardioversion—do not delay for medications. 1, 2

Cardioversion Protocol

• Monomorphic VT: Start with 100 J synchronized shock, escalate to 200 J then 360 J if needed 1, 3
• Polymorphic VT (resembling VF): Use unsynchronized 200 J shock 1, 3
• If patient is conscious but unstable: Provide immediate sedation before cardioversion 1, 2
• Start defibrillation at maximum output for in-hospital cardiac arrest, as VT/VF is more likely 1

Post-Cardioversion Management

If VT recurs after successful cardioversion, initiate antiarrhythmic therapy to prevent reinitiation 2:

• Intravenous amiodarone: 150 mg IV over 10 minutes, followed by 1.0 mg/min infusion for 6 hours, then 0.5 mg/min maintenance 1, 4
• Amiodarone is FDA-indicated for frequently recurring VF and hemodynamically unstable VT refractory to other therapy 4
• For breakthrough episodes: Give supplemental 150 mg amiodarone in 100 mL D5W over 10 minutes 4

Hemodynamically Stable Monomorphic VT

For stable monomorphic VT, intravenous procainamide is the first-line pharmacological agent, demonstrating the greatest efficacy for rhythm conversion. 2, 3, 5

Procainamide Administration

• Dose: 10-20 mg/kg IV at 50-100 mg/min over 10-20 minutes (maximum loading dose 12-17 mg/kg) 1, 2, 3
• Monitoring: Closely watch blood pressure and ECG for QRS widening (stop if QRS widens >50%) 2, 3
• Contraindications: Avoid in severe heart failure or acute MI 1, 2
• Maintenance: Follow with 1-4 mg/min infusion; reduce in renal dysfunction 1

Alternative Agents When Procainamide is Contraindicated

Use intravenous amiodarone in patients with heart failure, suspected myocardial ischemia, or impaired left ventricular function. 1, 2, 3

• Amiodarone dosing: 150 mg IV over 10 minutes, then 1.0 mg/min for 6 hours, then 0.5 mg/min maintenance 1, 2, 4
• Caveat: Amiodarone's antiarrhythmic effect may take up to 30 minutes, making it less suitable for urgent situations 3

Intravenous lidocaine is only moderately effective and should be considered second-line. 1, 2, 3

• Lidocaine dosing: 1.0-1.5 mg/kg bolus, supplemental boluses of 0.5-0.75 mg/kg every 5-10 minutes to maximum 3 mg/kg, then 2-4 mg/min infusion 1
• Reduce infusion rates in elderly patients, heart failure, or hepatic dysfunction 1

If Medications Fail

When pharmacological therapy is ineffective or contraindicated, proceed to synchronized cardioversion. 2

Polymorphic VT Management

The approach differs based on QT interval 2, 3:

Polymorphic VT with Normal QT (Ischemia-Related)

• First-line: Direct current cardioversion if hemodynamically compromised 2
• For recurrent episodes: IV beta-blockers, especially if ischemia suspected 2, 3
• IV amiodarone loading is useful for recurrent polymorphic VT without QT prolongation 2
• Urgent revascularization should be considered when ischemia cannot be excluded 2

Polymorphic VT with Long QT (Torsades de Pointes)

• IV magnesium: 8 mmol bolus followed by 2.5 mmol/h infusion 2, 3
• Overdrive pacing (atrial or ventricular) 2
• Beta-blockers for congenital long QT syndrome 2, 3
• Avoid isoproterenol in familial long QT syndrome 3

Special VT Subtypes

Left Ventricular Fascicular VT

For fascicular VT (RBBB morphology with left axis deviation), use IV verapamil or beta-blockers. 1

• This is the only scenario where calcium channel blockers are appropriate for wide-complex tachycardia 2

Refractory or Recurrent VT

Electrical Storm or Incessant VT

Urgent catheter ablation is recommended for patients with scar-related heart disease presenting with incessant VT or electrical storm. 1, 2

• Medical bridge therapy: Beta-blockers with or without amiodarone 2
• Catheter ablation is also recommended for ischemic heart disease patients with recurrent ICD shocks from sustained VT 2

Critical Pitfalls to Avoid

Never use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardia unless absolutely certain of fascicular VT diagnosis—they may precipitate hemodynamic collapse in structural VT. 2, 3

Do not assume a wide-complex tachycardia is supraventricular—when in doubt, treat as VT. 2, 3

Avoid excessive amiodarone loading rates and concentrations—intravenous amiodarone at much higher concentrations than recommended has resulted in hepatocellular necrosis and acute renal failure leading to death. 4

For amiodarone infusions >1 hour, do not exceed 2 mg/mL concentration unless using a central venous catheter, as higher concentrations cause peripheral vein phlebitis. 4

Amiodarone must be delivered by volumetric infusion pump (not drop counter sets) to avoid underdosing by up to 30%. 4