Initial Treatment for Stable Ventricular Tachycardia
For hemodynamically stable monomorphic ventricular tachycardia, intravenous procainamide is the first-line pharmacological agent, administered at 10 mg/kg IV at 50-100 mg/min over 10-20 minutes with continuous blood pressure and ECG monitoring. 1, 2
Immediate Assessment
Before initiating treatment, confirm the patient is truly hemodynamically stable by evaluating:
- Blood pressure (adequate perfusion pressure maintained) 1, 3
- Mental status (alert and oriented) 1, 3
- Absence of signs of shock or hypoperfusion 1, 3
Critical caveat: Any wide-QRS tachycardia should be presumed to be VT if the diagnosis is unclear—when in doubt, treat as VT. 1, 3
First-Line Pharmacological Management
Procainamide (Preferred Agent)
Procainamide demonstrates the greatest efficacy for rhythm conversion in stable monomorphic VT and is recommended as first-line therapy for patients without severe heart failure or acute MI. 4, 1, 2
Dosing specifics:
- 10 mg/kg IV at 50-100 mg/min over 10-20 minutes 1, 3
- Monitor blood pressure and ECG continuously during infusion 1, 2
- Stop infusion if hypotension develops or QRS widens significantly 2
Amiodarone (Alternative First-Line)
Switch to intravenous amiodarone instead of procainamide if the patient has:
- Heart failure or impaired left ventricular function 4, 1
- Suspected myocardial ischemia 4, 1
- Acute myocardial infarction 4, 1
Amiodarone dosing:
- Loading dose: 150 mg IV over 10 minutes 1, 5
- Followed by maintenance infusion of 1 mg/min for 6 hours, then 0.5 mg/min 5
- Use central venous catheter for concentrations >2 mg/mL 5
If Pharmacological Therapy Fails
If the initial antiarrhythmic agent does not terminate the tachycardia, do not administer additional different antiarrhythmic drugs—proceed directly to synchronized electrical cardioversion. 6
- Use 100-200 J synchronized cardioversion for monomorphic VT 1, 3
- Provide appropriate sedation before cardioversion in conscious patients 1
- Have full resuscitation equipment immediately available 3
Agents to Avoid
Never use calcium channel blockers (verapamil, diltiazem) in patients with VT and structural heart disease, as they may precipitate hemodynamic collapse. 1
Lidocaine is only moderately effective and should be considered second-line; its use is largely obsolete for stable VT. 1, 6
Post-Conversion Management
After successful conversion to sinus rhythm:
- Consider antiarrhythmic infusion to prevent recurrence, as atrial or ventricular premature complexes immediately after conversion may reinitiate tachycardia 4, 1
- Evaluate for underlying causes, particularly myocardial ischemia 3
- Obtain cardiology consultation, especially in patients with structural heart disease 3
- Consider ICD evaluation, as stable VT carries high mortality risk (33.6% at 3 years) and may be a marker for more malignant arrhythmias 7
Special Consideration for Polymorphic VT
If the VT is polymorphic rather than monomorphic: