From the Guidelines
Sustained ventricular tachycardia (VT) is diagnosed when a VT episode lasts for 30 seconds or longer, or requires intervention due to hemodynamic compromise before 30 seconds, as defined by the most recent guidelines 1. The criteria for sustained VT include a heart rate typically greater than 100 beats per minute, originating from the ventricles with a wide QRS complex, and showing atrioventricular dissociation.
- The QRS morphology often demonstrates a left bundle branch block pattern for right ventricular origins or right bundle branch block pattern for left ventricular origins.
- Sustained VT is distinguished from non-sustained VT, which terminates spontaneously within 30 seconds. This distinction is clinically important because sustained VT poses a greater risk of hemodynamic compromise and progression to ventricular fibrillation. The underlying mechanisms include reentry circuits, enhanced automaticity, or triggered activity, often occurring in patients with structural heart disease, previous myocardial infarction, cardiomyopathies, or electrolyte abnormalities. The most recent guidelines recommend direct current cardioversion for patients presenting with sustained VT and hemodynamic instability, with a Class I recommendation and Level C evidence 1. In patients who are hemodynamically stable, electrical cardioversion should be the first-line approach. Intravenous procainamide or flecainide may be considered for those who do not present with severe heart failure or acute myocardial infarction, while intravenous amiodarone may be considered in patients with heart failure or suspected ischemia. Immediate recognition is crucial as treatment may require electrical cardioversion, antiarrhythmic medications like amiodarone or lidocaine, or implantable cardioverter-defibrillator therapy depending on the clinical presentation, as supported by previous guidelines 2, 3.
From the FDA Drug Label
In patients with a history of sustained ventricular tachycardia, the incidence of Torsade de Pointes during sotalol treatment was 4% and worsened VT in about 1%; in patients with other less serious ventricular arrhythmias the incidence of Torsade de Pointes was 1% and new or worsened VT in about 0. 7%. The criteria for sustained ventricular tachycardia (VT) are not explicitly defined in the provided drug labels.
- The labels discuss the incidence of Torsade de Pointes and worsened VT in patients with a history of sustained ventricular tachycardia, but do not provide specific criteria for diagnosing sustained VT.
- The labels do mention that patients with sustained ventricular tachycardia and a history of congestive heart failure appear to have the highest risk for serious proarrhythmia (7%) 4, 5. However, this information does not provide a clear definition of sustained VT.
From the Research
Criteria for Sustained Ventricular Tachycardia (VT)
The criteria for sustained ventricular tachycardia (VT) are not explicitly defined in the provided studies. However, the following characteristics are associated with sustained VT:
- Sustained monomorphic ventricular tachycardia is a potentially life-threatening ventricular tachycardia 6
- Hemodynamically stable or unstable condition 7, 6
- Presence of heart disease or no heart disease at all 8
- Recurring or incessant VT 9
Treatment Options
Treatment options for sustained VT include:
- Antiarrhythmic drugs, such as class I antiarrhythmic drugs (e.g., lidocaine, ajmaline), class IC antiarrhythmic drugs (e.g., flecainide, propafenon), and amiodarone 7, 8, 6, 9
- Electrical cardioversion 7, 6, 9
- Radiofrequency catheter ablation 9
- Implantable cardioverter defibrillator (ICD) 9
Patient Selection
Patient selection for treatment options depends on various factors, including: