Medical Management of Stable Ventricular Tachycardia
For stable monomorphic VT, intravenous procainamide is the first-line pharmacologic agent, with IV amiodarone reserved for refractory cases or patients with heart failure. 1
Initial Assessment and Approach
When confronted with stable VT, first confirm hemodynamic stability and distinguish monomorphic from polymorphic VT, as management differs significantly. 1
Critical caveat: Wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear—never give calcium channel blockers (verapamil or diltiazem) as they can cause hemodynamic collapse or death in VT patients. 1
Monomorphic VT Management Algorithm
First-Line Pharmacologic Treatment
Intravenous procainamide is the preferred initial agent for stable monomorphic VT (Class IIa recommendation). 1
- Dosing: 10 mg/kg at 50-100 mg/min IV over 10-20 minutes 2
- Advantages: Most appropriate when early slowing of VT rate and termination are desired 1
- Monitoring: Close blood pressure and cardiovascular status monitoring required, especially with congestive heart failure or severe hypotension 1
- Evidence: Procainamide demonstrates the greatest efficacy among medical options for stable monomorphic VT 2
Second-Line Options
Intravenous amiodarone should be used when: 1
- VT is refractory to procainamide
- VT is recurrent despite other agents
- Patient has severe congestive heart failure (where procainamide is relatively contraindicated)
Important limitation: IV amiodarone is NOT ideal for early conversion of stable monomorphic VT—it works more slowly than procainamide. 1
Intravenous lidocaine (Class IIb) may be reasonable specifically when VT is associated with acute myocardial ischemia or infarction. 1
Non-Pharmacologic Options
Direct current cardioversion with appropriate sedation can be performed at any point in the treatment cascade and remains the most effective and rapid means of termination. 1
Transvenous catheter pace termination can be useful for VT refractory to cardioversion or frequently recurrent despite antiarrhythmic medication. 1
Polymorphic VT Management
The approach differs based on QT interval: 1
Polymorphic VT WITHOUT Long QT Syndrome
- Intravenous beta blockers (Class I) especially if ischemia suspected 1
- Intravenous amiodarone loading (Class I) 1
- Urgent angiography with revascularization when myocardial ischemia cannot be excluded 1
- IV lidocaine (Class IIb) may be reasonable if associated with acute MI 1
Polymorphic VT WITH Long QT Syndrome
- Familial long QT: IV magnesium, pacing, beta-blockers (avoid isoproterenol) 1
- Acquired long QT: IV magnesium; consider pacing or IV isoproterenol if accompanied by bradycardia 1
Critical Management Priorities
Before initiating antiarrhythmic therapy, correct: 1
- Hypokalemia
- Ongoing ischemia
- Other reversible causes
Common Pitfalls to Avoid
Never use calcium channel blockers (verapamil, diltiazem) for wide-QRS tachycardia of unknown origin—this is a Class III recommendation (harmful). 1
Don't assume amiodarone is first-line for stable monomorphic VT—procainamide is more appropriate for acute conversion. 1
Don't delay cardioversion if pharmacologic therapy fails or patient becomes unstable—electrical cardioversion remains most efficacious. 2
Monitor blood pressure closely during procainamide infusion, particularly in patients with heart failure. 1