Immediate Treatment for Ventricular Tachycardia
For hemodynamically unstable VT, perform immediate synchronized cardioversion starting at 100 J (biphasic) for monomorphic VT, or unsynchronized high-energy defibrillation (200 J) for polymorphic VT. 1, 2
Initial Assessment: Determine Hemodynamic Stability
Your first critical step is rapidly assessing hemodynamic stability by looking for:
- Hypotension (systolic BP <90 mmHg)
- Altered mental status or loss of consciousness
- Chest pain or acute ischemic symptoms
- Signs of shock (cool extremities, poor perfusion)
- Acute heart failure (pulmonary edema, severe dyspnea) 1, 3
This assessment determines your immediate treatment pathway and should take seconds, not minutes.
Treatment Algorithm for Unstable VT
Monomorphic VT (Regular Rhythm)
Deliver synchronized cardioversion immediately at 100 J using a biphasic defibrillator. 1, 2 If the patient is conscious but unstable, provide rapid sedation but do not delay cardioversion if the patient is extremely unstable or deteriorating. 3, 4 If the first shock fails, escalate energy in a stepwise fashion. 2
Polymorphic VT (Irregular Rhythm)
Treat polymorphic VT as ventricular fibrillation using unsynchronized high-energy shocks at 200 J (defibrillation doses). 1, 2 Do not attempt synchronized cardioversion for polymorphic VT, as the device may fail to sense a consistent QRS complex and delay shock delivery. 2
Critical pitfall: Never use synchronized cardioversion for polymorphic VT or pulseless VT—these require immediate defibrillation. 2
Treatment Algorithm for Stable VT
Even in hemodynamically stable patients, electrical cardioversion remains first-line therapy and is highly effective. 1, 3 However, you have time to consider pharmacologic options:
Pharmacologic Options (in order of preference):
Procainamide is the most efficacious pharmacologic agent for stable monomorphic VT in patients without severe heart failure or acute MI, dosed at 10 mg/kg IV at 50-100 mg/min over 10-20 minutes with continuous BP and ECG monitoring. 1, 5 This carries a Class IIa recommendation compared to Class IIb for amiodarone. 5
Amiodarone is preferred for patients with heart failure or suspected myocardial ischemia, dosed at 150 mg IV over 10 minutes followed by maintenance infusion at 1 mg/min for 6 hours, then 0.5 mg/min. 1, 3, 6 Amiodarone is indicated for frequently recurring VF and hemodynamically unstable VT refractory to other therapy. 6
Critical caveat: Avoid calcium channel blockers (diltiazem, verapamil) in patients with VT and structural heart disease, as they may precipitate hemodynamic collapse. 3, 4 Only use these agents if you are certain the rhythm is fascicular VT (RBBB morphology with left axis deviation). 3
Post-Cardioversion Management
After successful conversion:
- Maintain continuous cardiac monitoring for VT recurrence 1
- Obtain immediate 12-lead ECG to assess for ST-elevation or ischemic changes 1
- Correct electrolyte abnormalities immediately (potassium, magnesium) 1
- Start IV beta-blockers to prevent recurrent arrhythmias 1
- Consider antiarrhythmic infusion if VT recurs after cardioversion 4
Special Considerations for Refractory VT
For incessant VT or electrical storm despite optimal medical therapy, urgent catheter ablation is indicated, particularly in patients with scar-related heart disease. 1, 3 Consider transvenous overdrive pacing if VT is frequently recurrent and catheter ablation is not immediately available. 1
Common Pitfalls to Avoid
- Never delay cardioversion in unstable patients while attempting pharmacologic conversion—this is the most dangerous error. 3, 4
- Do not use synchronized mode for polymorphic VT—it requires unsynchronized defibrillation. 2
- Avoid assuming wide-complex tachycardia is supraventricular—when in doubt, treat as VT. 4
- Do not use calcium channel blockers empirically for wide-complex tachycardia unless certain it is fascicular VT. 3, 4
- Do not under-monitor after successful conversion—recurrence is common and requires vigilance. 3