What is the immediate treatment for a patient presenting with ventricular tachycardia?

Immediate Treatment for Ventricular Tachycardia

For hemodynamically unstable VT (hypotension, altered mental status, shock, chest pain, heart failure, or syncope), proceed immediately to synchronized direct current cardioversion without delay—this takes absolute priority over all other interventions. 1, 2, 3

Initial Assessment Algorithm

Step 1: Assess hemodynamic stability within seconds of presentation 1, 2

• Unstable indicators: hypotension, altered mental status, signs of shock, ischemic chest discomfort, acute heart failure, or syncope 3
• If unstable: proceed directly to cardioversion—do not attempt pharmacological conversion first 2
• If hypotensive but conscious: provide immediate sedation before cardioversion 1, 2

Step 2: Obtain 12-lead ECG if patient is stable 2

• Presume wide-complex tachycardia is VT until proven otherwise 1, 3
• Confirm VT using ECG criteria: QRS >0.14s with RBBB or >0.16s with LBBB pattern, AV dissociation, fusion beats, RS interval >100ms in precordial leads 1, 3

Cardioversion Protocol for Unstable Patients

Use synchronized cardioversion as first-line treatment 1, 2

• For monomorphic VT with rates >150 bpm: use 100 J synchronized discharge 1
• For polymorphic VT resembling VF: use unsynchronized 200 J discharge 1
• Begin with maximum output to ensure successful termination 2
• If no defibrillator immediately available: attempt precordial thump while preparing equipment 2

Pharmacological Management for Stable Monomorphic VT

Intravenous procainamide is the preferred first-line agent for stable monomorphic VT when early termination is desired, demonstrating greatest efficacy for rhythm conversion 1

• Dosing: 10 mg/kg IV at 50-100 mg/min over 10-20 minutes with close BP and ECG monitoring 1
• However, switch to IV amiodarone instead of procainamide in patients with heart failure, suspected myocardial ischemia, or impaired left ventricular function 1, 2

Amiodarone dosing for stable VT: 1, 4

• Loading dose: 150 mg IV over 10 minutes 1
• Followed by maintenance infusion: 1 mg/min for 6 hours, then 0.5 mg/min 4
• Use central venous catheter for concentrations >2 mg/mL to avoid peripheral vein phlebitis 4
• Must be delivered by volumetric infusion pump 4

Alternative agents for stable monomorphic VT: 1

• Sotalol may be considered for hemodynamically stable sustained VT, including post-MI patients 1
• IV lidocaine is only moderately effective and should be considered second-line 1, 2

Management of Polymorphic VT

Direct current cardioversion is first-line for hemodynamically compromised polymorphic VT 1

For recurrent polymorphic VT: 1

• IV beta-blockers are first-line, especially if ischemia is suspected or cannot be excluded 1, 2
• IV amiodarone loading is useful for recurrent polymorphic VT in the absence of QT prolongation 1
• For polymorphic VT with long QT (torsades de pointes): IV magnesium for recurrences, overdrive pacing, and beta-blockers for congenital long QT 1

Urgent revascularization should be considered when ischemia cannot be excluded 1

Post-Conversion Management

If VT recurs after cardioversion, initiate antiarrhythmic drug therapy to prevent acute reinitiation 1

• For recurrent or incessant VT: IV amiodarone or procainamide followed by VT ablation 1
• Urgent catheter ablation is recommended for scar-related heart disease with incessant VT or electrical storm 1, 2
• Beta-blockers with or without amiodarone are recommended for VT storm 1

Evaluate and correct underlying causes: 2

• Ongoing myocardial ischemia, electrolyte abnormalities (especially potassium and magnesium), hypoxia, and acid-base disturbances 2, 3

Critical Pitfalls to Avoid

Never use calcium channel blockers (verapamil, diltiazem) in VT with structural heart disease—they may precipitate hemodynamic collapse 1, 2

• Only consider verapamil/diltiazem if absolutely certain of fascicular VT diagnosis (LV fascicular VT with RBBB morphology and left axis deviation) 1, 2

Never delay cardioversion in unstable patients while attempting pharmacological conversion 2

Never assume wide-complex tachycardia is supraventricular—when in doubt, treat as VT 1, 3

Distinguish accelerated idioventricular rhythm (ventricular rate <120 bpm) from true VT, as it is usually a harmless reperfusion rhythm requiring no treatment 2