Introduction
Monomorphic ventricular tachycardia (VT) is a regular wide-complex tachycardia with uniform QRS morphology, indicating that ventricular activation originates from a single focus or re-entry circuit in the ventricles. It is commonly associated with structural heart disease such as ischemic cardiomyopathy or prior myocardial infarction.
Management follows principles outlined in ACLS, AHA/ACC/HRS, and ESC ventricular arrhythmia guidelines, with treatment decisions primarily based on hemodynamic stability and presence of a pulse.
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1. Initial Assessment
Immediate evaluation focuses on hemodynamic stability.
Signs of Hemodynamic Instability
Hypotension
Altered mental status
Signs of shock
Ischemic chest pain
Acute heart failure / pulmonary edema
Presence of any of these indicates unstable VT, requiring urgent electrical therapy.
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2. Management Algorithm
A. Pulseless Monomorphic VT
Treat according to cardiac arrest protocol.
Management
1. Immediate defibrillation
2. High-quality CPR
3. Epinephrine
4. Amiodarone 300 mg IV bolus after refractory shock
5. Continue ACLS cycles
Pulseless VT is treated identically to ventricular fibrillation in ACLS protocols.
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3. Monomorphic VT with Pulse
Management depends on stability.
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A. Unstable Monomorphic VT
First-line Treatment
Immediate synchronized DC cardioversion
Typical starting energy:
100–150 J biphasic
If unsuccessful, escalate energy and repeat cardioversion.
Adjunctive Therapy
If VT recurs after cardioversion:
IV amiodarone
Treat underlying cause (ischemia, electrolyte imbalance)
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B. Stable Monomorphic VT
Stable patients allow pharmacologic therapy or elective cardioversion.
First-line Antiarrhythmic Drugs
1. Procainamide
Preferred drug for stable monomorphic VT.
Dose:
10 mg/kg IV infusion (20–50 mg/min)
Evidence shows higher VT termination and fewer adverse events compared with amiodarone in stable VT.
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2. Amiodarone
Dose:
150 mg IV over 10 minutes
Followed by infusion
1 mg/min for 6 hours
0.5 mg/min for 18 hours
Used especially when:
Structural heart disease
Heart failure
Post-MI VT
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3. Sotalol
Alternative option if QT interval is normal.
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Important Principle
Avoid giving multiple antiarrhythmic drugs sequentially without expert consultation due to pro-arrhythmia risk.
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4. Special Types of Monomorphic VT
Fascicular VT
Responds to IV verapamil
Outflow Tract VT
May respond to adenosine
Ischemic VT
Requires urgent coronary evaluation and revascularization.
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5. Long-Term Management
After acute stabilization, management focuses on preventing recurrence and sudden cardiac death.
Options
1. Implantable Cardioverter-Defibrillator (ICD)
Standard therapy for secondary prevention of VT/VF.
2. Antiarrhythmic Drugs
Amiodarone
Sotalol
Beta-blockers
3. Catheter Ablation
Indicated for:
Recurrent VT
Electrical storm
Drug-refractory VT
4. Treat Underlying Cause
Ischemia
Electrolyte imbalance
Cardiomyopathy
Drug toxicity
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6. Electrical Storm Management
Electrical storm = ≥3 VT episodes in 24 hours
Management includes:
IV amiodarone
Beta-blocker
Sedation
Urgent catheter ablation
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7. Simplified Clinical Algorithm
Pulseless VT → Defibrillation (ACLS)
VT with Pulse
Unstable → Immediate synchronized cardioversion
Stable →
Procainamide
Amiodarone
Sotalol
Consider cardioversion
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Key Guideline Points
Hemodynamic stability determines treatment strategy.
Synchronized cardioversion is first-line for unstable VT.
Procainamide is preferred pharmacologic therapy in stable VT.
Amiodarone is widely used in structural heart disease.
ICD and catheter ablation are essential for long-term prevention.
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