What is the recommended management of ventricular tachycardia, including assessment of hemodynamic stability, first‑line drug therapy, and criteria for electrical cardioversion, catheter ablation, or implantable cardioverter‑defibrillator placement?

Management of Ventricular Tachycardia

For hemodynamically unstable VT (hypotension, altered mental status, shock, chest pain, heart failure), perform immediate synchronized direct current cardioversion without delay—this is the definitive first-line treatment that saves lives. 1

Initial Assessment: Stable vs. Unstable

Immediately assess hemodynamic stability by checking for:

• Hypotension (systolic BP <90 mmHg) 1
• Altered mental status or loss of consciousness 1, 2
• Signs of shock (cold extremities, poor perfusion) 1
• Acute heart failure (pulmonary edema, severe dyspnea) 1
• Ongoing chest pain suggesting ischemia 1

If ANY of these are present, the patient is unstable—proceed directly to electrical cardioversion. Do not waste time obtaining a 12-lead ECG or attempting pharmacologic therapy. 1, 2

For conscious but hypotensive patients, provide immediate sedation before cardioversion. 2

Electrical Cardioversion Protocol

For Unstable VT:

• Monomorphic VT >150 bpm: Use 100 J synchronized cardioversion as initial energy 2
• Polymorphic VT resembling VF: Use unsynchronized 200 J defibrillation 2
• If no defibrillator is immediately available, consider a precordial thump for witnessed, monitored VT while preparing equipment 1, 3

For Stable VT:

Synchronized electrical cardioversion remains the most effective treatment even in stable patients and should be considered first-line. 2 However, pharmacologic therapy is a reasonable alternative if cardioversion is not immediately available or preferred. 1

Pharmacologic Management for Stable Monomorphic VT

Before initiating drug therapy, obtain a 12-lead ECG to confirm VT and determine if monomorphic or polymorphic. 1, 2

First-Line Drug Selection Algorithm:

1. If NO heart failure, NO acute MI, and LVEF >40%:

• Intravenous procainamide is the preferred agent (greatest efficacy for rhythm conversion) 2, 4
• Dose: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 2, 4
• Monitor BP and ECG continuously during infusion 2, 4
• Alternative: IV flecainide may be considered 1

2. If heart failure present, suspected ischemia, or LVEF ≤40%:

• Intravenous amiodarone is preferred over procainamide (better tolerated in these contexts) 1, 2, 3
• Loading dose: 150 mg IV over 10 minutes, followed by maintenance infusion 2, 3

3. Special case—LV fascicular VT (RBBB morphology with left axis deviation):

• Intravenous verapamil OR beta-blockers are the agents of choice 1, 2
• This is the ONLY scenario where calcium channel blockers are safe in VT 2

4. Second-line options:

• Intravenous lidocaine: Only moderately effective, reserve as second-line 1, 2, 3
• Intravenous sotalol: May be considered for stable monomorphic VT 1, 2

Critical Contraindications and Pitfalls

NEVER Use Calcium Channel Blockers (Verapamil/Diltiazem) for VT with Structural Heart Disease:

This is the most dangerous pitfall—calcium channel blockers can precipitate ventricular fibrillation and hemodynamic collapse in structural VT. 2, 3 The ONLY exception is confirmed LV fascicular VT. 2

Other AV Nodal Blockers Are Also Contraindicated:

Do not use adenosine, digoxin, or other AV nodal blocking agents for wide-complex tachycardia unless you are absolutely certain it is supraventricular. 1

When in Doubt, Treat as VT:

If you cannot definitively distinguish VT from SVT with aberrancy, always presume VT and treat accordingly. 1, 2 The consequences of treating VT as SVT are far more dangerous than the reverse.

Management of Polymorphic VT

If Hemodynamically Compromised:

• Immediate unsynchronized defibrillation 2

If Stable:

• Intravenous beta-blockers for recurrent polymorphic VT, especially if ischemia suspected 2
• Intravenous amiodarone loading for recurrent polymorphic VT in absence of QT prolongation 2
• Urgent revascularization if ischemia cannot be excluded 2

For Torsades de Pointes (Polymorphic VT with Long QT):

• Intravenous magnesium sulfate for recurrences 2
• Overdrive pacing (atrial or ventricular) 2
• Beta-blockers for congenital long QT syndrome 2

Post-Conversion Management

After successful conversion:

• Correct underlying causes: ischemia, electrolytes (especially potassium), hypoxia, acid-base disturbances 3
• Initiate beta-blocker therapy at maximal tolerated doses (reduces recurrent VT/VF by 52%, HR 0.48) 3
• Consider adding amiodarone to beta-blocker (reduces ICD shocks by 73%, HR 0.27) 3
• Continuous ECG monitoring for at least 3 days 3
• Optimize heart failure medications if LV dysfunction present 3

Catheter Ablation Indications

Class I Recommendations (Must Do):

• Urgent catheter ablation for scar-related heart disease with incessant VT or electrical storm 1, 2
• Catheter ablation for ischemic heart disease with recurrent ICD shocks due to sustained VT 1, 2

Class IIa Recommendation (Should Consider):

• Catheter ablation after first episode of sustained VT in patients with ischemic heart disease and an ICD 1, 2

ICD Implantation Criteria

Class I Indications (Definitive):

• Cardiac arrest survivors with documented VT/VF not due to reversible cause 1
• Sustained VT with severe hemodynamic compromise (syncope, near-syncope, heart failure, shock, angina) 1

Class IIa/IIb Indications:

• Sustained VT without hemodynamic compromise if LVEF ≤40% 1
• Non-sustained VT with LVEF ≤40%, ≥4 days post-MI, with inducible VF or sustained VT at EP study 1
• Syncope with inducible VT/VF at EP study when drug therapy ineffective 1

Class III (Do Not Implant):

• VT/VF within 48 hours of acute MI (transient/reversible cause) 1
• Incessant VT (ablation first) 1
• Terminal illness with life expectancy <6 months 1