From the Guidelines
Ventricular tachycardia (VT) lasting for 9 beats is considered non-sustained VT (NSVT) and requires prompt evaluation, with a focus on assessing for underlying heart disease and preventing recurrence, as indicated by the 2017 AHA/ACC/HRS guideline 1. The immediate management depends on the patient's hemodynamic stability. If the patient is stable, no immediate intervention is needed, but they should be referred to a cardiologist for comprehensive evaluation. Initial workup should include:
- A 12-lead ECG to assess for signs of ischemia or prior myocardial infarction
- Cardiac biomarkers to evaluate for myocardial damage
- Electrolytes (particularly potassium and magnesium) to identify potential triggers for NSVT
- An echocardiogram to assess for structural heart disease, such as left ventricular dysfunction For patients with underlying heart disease, beta-blockers such as metoprolol 25-100 mg twice daily or carvedilol 3.125-25 mg twice daily are often prescribed to prevent recurrence, as they have been shown to reduce the risk of adverse outcomes in patients with cardiovascular disease 1. If the patient has reduced ejection fraction, an implantable cardioverter-defibrillator (ICD) may be considered, especially if the NSVT is associated with symptoms or occurs in the setting of prior myocardial infarction. The underlying mechanism of NSVT involves abnormal electrical impulses originating from the ventricles, often triggered by myocardial scarring, electrolyte abnormalities, or medication effects. Even brief runs of VT can indicate increased risk for sustained arrhythmias and sudden cardiac death, particularly in patients with structural heart disease, making thorough evaluation essential, as highlighted in the 2017 AHA/ACC/HRS guideline 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Definition and Classification of Ventricular Tachycardia
- Ventricular tachycardia (VT) is defined as a ventricular dysrhythmia with a rate of at least 120 beats/min and QRS > 120 ms without regularly occurring P:QRS association 2
- VT is classified based on hemodynamic status and appearance, with stable, monomorphic VT being a specific type that is controversial in terms of treatment 2
Treatment of Stable Monomorphic Ventricular Tachycardia
- Direct current cardioversion is the most efficacious treatment for stable monomorphic VT 2
- Procainamide is the most effective medical management option, with a maximum dose of 10 mg/kg at 50-100 mg/min intravenous (IV) over 10-20 min, and monitoring of blood pressure and electrocardiogram is recommended 2
- Amiodarone is also used for the treatment of VT, but its efficacy has not been empirically examined in the prehospital setting until recently 3
- A systematic review of the literature found that procainamide, ajmaline, and sotalol were all superior to lidocaine for the treatment of stable, monomorphic VT, while amiodarone was not more effective than procainamide 4
Efficacy of Amiodarone in Ventricular Tachycardia
- Amiodarone has emerged as the leading antiarrhythmic therapy for termination and prevention of ventricular arrhythmia in different clinical settings due to its proven efficacy and safety 5
- A study found that amiodarone was relatively safe and moderately effective for the treatment of sustained stable VT in the prehospital setting, with approximately half of the patients treated with amiodarone reverting from VT while under paramedic care 3
- However, given recent evidence of increased efficacy of procainamide for stable VT, further studies are required in the prehospital setting to compare these two drugs 3
Comparison of Antiarrhythmic Drugs
- A systematic review found that procainamide, ajmaline, and sotalol were all superior to lidocaine for the treatment of stable, monomorphic VT 4
- The same review found that amiodarone was not more effective than procainamide for the treatment of stable, monomorphic VT 4
- Another study found that ibutilide was effective in converting atrial flutter to sinus rhythm, with efficacy rates of 38-76% compared to conversion rates of 5-13% with intravenous flecainide, propafenone, or verapamil 6