Management of Short Runs of Conscious Ventricular Tachycardia
For hemodynamically stable patients with short runs of conscious VT, intravenous procainamide is the preferred first-line pharmacological agent, administered at 10 mg/kg IV at 50-100 mg/min over 10-20 minutes, with close monitoring of blood pressure and ECG. 1, 2
Initial Assessment
When encountering a patient with suspected short runs of VT who remains conscious, immediately assess hemodynamic stability by evaluating:
- Blood pressure (hypotension suggests instability)
- Mental status (altered consciousness indicates hemodynamic compromise)
- Signs of hypoperfusion (cool extremities, delayed capillary refill, oliguria) 1
Critical principle: Any wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear—when in doubt, treat as VT. 1, 2 This is a common pitfall that can lead to dangerous mismanagement.
Obtain a 12-Lead ECG
For all hemodynamically stable patients, obtain a 12-lead ECG to:
- Confirm VT diagnosis using criteria including QRS width >140 ms with RBBB pattern or >160 ms with LBBB pattern, AV dissociation, fusion or capture beats 2
- Classify as monomorphic (consistent QRS morphology) or polymorphic (changing QRS morphology) 1
- Identify QR complexes indicating myocardial scar, which is diagnostic for VT and present in ~40% of post-MI VT 2
Pharmacological Management for Stable Monomorphic VT
First-Line Agent: Procainamide
Intravenous procainamide demonstrates the greatest efficacy for rhythm conversion and is recommended as the preferred first-line agent for hemodynamically stable patients with monomorphic VT. 1, 2, 3
Dosing protocol:
- 10 mg/kg IV at 50-100 mg/min over 10-20 minutes
- Monitor blood pressure and ECG continuously during infusion
- Stop if hypotension develops or QRS widens by >50% 1, 2
Important caveat: Avoid procainamide in patients with severe heart failure or acute myocardial infarction. 2
Alternative Agents
Intravenous amiodarone is the preferred agent over procainamide in specific clinical contexts:
- Patients with heart failure
- Suspected myocardial ischemia
- Impaired left ventricular function
- When VT is refractory to countershock 1, 2
Amiodarone dosing: 150 mg IV over 10 minutes, followed by maintenance infusion. 2
Intravenous beta-blockers are reasonable alternatives, though evidence for effectiveness is more limited compared to procainamide. 1 They are particularly useful if ischemia is suspected. 1
Intravenous lidocaine might be reasonable if VT is associated with acute myocardial ischemia, but it is only moderately effective and should be considered second-line. 1, 2
When Pharmacological Therapy Fails
Synchronized cardioversion is recommended when pharmacological therapy is ineffective or contraindicated, even in hemodynamically stable patients. 1, 2
- Start with 100-200 J for synchronized cardioversion of monomorphic VT 1
- Have resuscitation equipment readily available 1
Critical Pitfalls to Avoid
Never use calcium channel blockers (verapamil, diltiazem) for wide-complex tachycardias unless absolutely certain of fascicular VT diagnosis—they may precipitate hemodynamic collapse in structural VT. 2 This is one of the most dangerous errors in VT management.
Never assume a wide-complex tachycardia is supraventricular—always treat as VT when uncertain. 2
Post-Conversion Management
After successful conversion:
- Evaluate for underlying causes including myocardial ischemia, electrolyte abnormalities, and structural heart disease 1
- Consider maintenance antiarrhythmic therapy to prevent recurrence 1
- Cardiology consultation is mandatory, particularly for patients with structural heart disease 1
- Consider ICD evaluation for patients with structural heart disease and sustained VT, as this is associated with high risk of recurrence and sudden death 1
Special Considerations for Recurrent Episodes
If VT recurs after initial conversion: