How should ventricular tachycardia be managed acutely and for long‑term secondary prevention?

Management of Ventricular Tachycardia

For hemodynamically unstable VT (hypotension, altered mental status, shock, pulmonary edema, or chest pain), proceed immediately to synchronized electrical cardioversion without delay—this is the definitive first-line treatment that saves lives. 1, 2

Acute Management Algorithm

Step 1: Assess Hemodynamic Stability

Unstable VT is defined by any of the following 1, 2:

• Systolic blood pressure < 90 mmHg
• Altered mental status or loss of consciousness
• Clinical signs of shock (cold extremities, poor perfusion)
• Acute heart failure (pulmonary edema, severe dyspnea)
• Ongoing chest pain suggesting myocardial ischemia

If ANY of these are present, skip pharmacologic therapy and cardiovert immediately. 1, 2

Step 2: Immediate Cardioversion for Unstable VT

Energy settings 1, 2:

• Monomorphic VT with rate >150 bpm: 100 J synchronized shock initially
• Polymorphic VT resembling VF: 200 J unsynchronized defibrillation
• If first shock fails, escalate sequentially: 200 J → 300 J → 360 J 2

Sedation: Provide brief sedation if the patient is conscious and time permits, but do not delay cardioversion 1, 2

Step 3: Management of Stable Monomorphic VT

Even in hemodynamically stable patients, synchronized cardioversion remains the most effective first-line therapy and should be strongly considered before pharmacologic options 1, 2. However, if cardioversion is unavailable or deferred, proceed with pharmacologic management based on the clinical context:

For patients WITHOUT heart failure, acute MI, or LVEF >40%:

Intravenous procainamide is the preferred first-line agent 2:

• Dose: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes
• Greatest efficacy for rhythm conversion among antiarrhythmics
• Monitor blood pressure and ECG continuously during infusion
• Do NOT use in severe heart failure or acute MI 2

Alternative: IV flecainide may be considered 2

For patients WITH heart failure, suspected ischemia, or LVEF ≤40%:

Intravenous amiodarone is preferred over procainamide 1, 2:

• Loading dose: 150 mg IV over 10 minutes
• Followed by maintenance infusion
• Better tolerated hemodynamically in these high-risk patients
• Important caveat: Onset is slow (20-30 minutes), making it suboptimal for rapid conversion 2

Special case—Left ventricular fascicular VT (RBBB morphology with left axis deviation):

Intravenous verapamil or beta-blockers are the agents of choice 2:

• This is the ONLY scenario where calcium channel blockers are safe for VT
• Do not use standard VT protocols for this specific entity

Second-line agents when first-line drugs fail or are contraindicated:

• Sotalol: May be considered for stable sustained monomorphic VT, including post-MI patients 2
• Lidocaine: Only moderately effective; reserve as second-line (1 mg/kg bolus, then 0.5 mg/kg every 8-10 min) 1, 2

Step 4: Management of Polymorphic VT

For polymorphic VT with normal QT 1, 2:

• Direct current cardioversion for hemodynamically compromised patients
• IV beta-blockers for recurrent polymorphic VT, especially if ischemia suspected
• IV amiodarone loading for recurrent episodes in absence of QT prolongation
• Urgent revascularization if ischemia cannot be excluded 2

For polymorphic VT with prolonged QT (torsades de pointes) 2:

• IV magnesium for recurrences
• Overdrive pacing (atrial or ventricular)
• Beta-blockers for congenital long QT syndrome
• Avoid isoproterenol in familial long QT 2
• For pause-dependent/bradycardia-associated polymorphic VT, use temporary pacing or IV isoproterenol to increase heart rate 2

Critical Pitfalls to Avoid

Never use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardia in structural heart disease—they can precipitate ventricular fibrillation and hemodynamic collapse 1, 2. The sole exception is confirmed LV fascicular VT 2.

When in doubt about the diagnosis of wide-complex tachycardia, always treat as VT—assuming it is supraventricular with aberrancy can be fatal 2.

Do not delay cardioversion in favor of additional pharmacologic therapy once initial drug therapy has been attempted—waiting offers no benefit and may allow hemodynamic deterioration 2.

Avoid AV-nodal blocking agents (adenosine, digoxin) for wide-complex tachycardias unless supraventricular origin is certain 2.

Post-Conversion Management

For recurrent or incessant VT after successful cardioversion 2:

• Administer IV antiarrhythmic therapy (procainamide or amiodarone) to prevent immediate re-initiation
• Evaluate for urgent catheter ablation as definitive therapy
• Beta-blockers with or without amiodarone are recommended for VT storm 2

Monitor continuously for premature complexes after cardioversion, as these ectopic beats can precipitate VT recurrence 2.

Long-Term Secondary Prevention

Catheter Ablation Indications

Class I (must do) 1, 2:

• Urgent catheter ablation for scar-related heart disease with incessant VT or electrical storm
• Ischemic heart disease with recurrent ICD shocks due to sustained VT

Class IIa (should consider) 1, 2:

• After first episode of sustained VT in patients with ischemic heart disease who have an ICD
• Recurrent VT despite optimal medical treatment, followed by ICD implantation

ICD Implantation Criteria

Class I (definitive indication) 2:

• Survivors of cardiac arrest with documented VT/VF not due to reversible cause
• Sustained VT with severe hemodynamic compromise (syncope, near-syncope, heart failure, shock, or angina)

Class IIa/IIb (may consider) 2:

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

Class III (do NOT implant) 2:

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

Pharmacologic Secondary Prevention

Beta-blockers are recommended for all patients post-acute coronary syndrome without contraindications 1.

For patients with heart failure where ICD is not feasible, amiodarone, sotalol, and/or beta-blockers may be considered as pharmacologic alternatives to suppress symptomatic ventricular tachyarrhythmias 1.

Prophylactic antiarrhythmic drugs (other than beta-blockers) are NOT recommended and may be harmful 1.

Asymptomatic non-sustained VT should NOT be treated with antiarrhythmic medication, as there is no evidence that suppression improves prognosis 1.

Context-Specific Considerations

VT in Acute Coronary Syndrome

Correction of ischemia is the early priority 1, 2:

• Most post-MI VT/VF occurs within first 48 hours 2
• Beta-blockers improve mortality in recurrent polymorphic VT with acute MI 1, 2
• For recurrent/incessant polymorphic VT due to acute ischemia: revascularization and beta-blockade followed by IV antiarrhythmics (procainamide or amiodarone) 2
• VT/VF occurring >48 hours post-MI deserves careful evaluation including consideration of EP studies 2

VT in Heart Failure

Arrhythmia management occurs concurrently with hemodynamic stabilization 1:

• Search for correctable mechanical problems (monitoring catheters causing arrhythmias)
• Meticulous attention to electrolytes, oxygen status, and medications
• Early cardioversion preferred over pharmacologic termination for poorly tolerated ventricular arrhythmias 1
• IV amiodarone has gained widespread acceptance for life-threatening arrhythmias during acute HF due to rapid onset and superior safety profile 1