From the Guidelines
The most common cause of ventricular tachycardia (VT) is coronary artery disease, particularly in patients who have experienced a myocardial infarction (heart attack). Ventricular tachycardia occurs when abnormal electrical signals in the ventricles cause the heart to beat too quickly, typically at a rate of 100-250 beats per minute. In patients with coronary artery disease, scar tissue from previous heart attacks creates areas of damaged heart muscle that disrupt normal electrical conduction, creating circuits for reentrant arrhythmias.
Key Causes of Ventricular Tachycardia
- Coronary artery disease
- Cardiomyopathies (both dilated and hypertrophic) 1
- Valvular heart disease
- Electrolyte abnormalities (particularly potassium and magnesium)
- Medication side effects
- Congenital heart conditions According to the study by Jessup et al 1, the cardiac mortality of patients with all types of ventricular tachyarrhythmias is high, resulting from progressive heart failure, as well as from sudden death.
Management of Ventricular Tachycardia
- Acute management: electrical cardioversion for unstable patients
- Antiarrhythmic medications like amiodarone (150-300 mg IV bolus followed by infusion) for more stable situations
- Long-term management: addressing the underlying cause, which may include coronary revascularization, implantable cardioverter-defibrillators, or antiarrhythmic medications depending on the specific clinical scenario. The use of implanted devices that terminate sustained arrhythmias can decrease sudden death, as discussed in the guidelines by Jessup et al 1.
From the FDA Drug Label
The most important treatment-emergent adverse effects were hypotension, asystole/cardiac arrest/ electromechanical dissociation (EMD), cardiogenic shock, congestive heart failure, bradycardia, liver function test abnormalities, VT, and AV block. The most common adverse effects leading to discontinuation of amiodarone HCl injection therapy were hypotension (1.6%), asystole/cardiac arrest/EMD (1.2%), VT (1. 1%), and cardiogenic shock (1%).
The FDA drug label does not answer the question.
From the Research
Causes of Ventricular Tachycardia
- The most common cause of ventricular tachycardia (VT) is a myocardial scar from prior infarct, which leads to sustained monomorphic VT in patients with structural heart disease 2.
- Coronary artery disease is a common etiological factor for VT, accounting for 39% of patients in one study 3.
- Other causes of VT include non-ischemic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, sarcoidosis, Chagas disease, and repaired congenital heart disease 4.
Mechanisms of Ventricular Tachycardia
- Scar-mediated reentry is the predominant mechanism of VT in patients with coronary artery disease and previous myocardial infarction 4.
- Ischemia-induced electrophysiological changes and genetic factors can also contribute to the occurrence of VT during the prehospital phase of acute myocardial infarction 5.
Clinical Characteristics of Ventricular Tachycardia
- VT can be hemodynamically unstable, especially in patients with acute myocardial infarction or polymorphic VT 3.
- The 12-lead electrocardiogram can be helpful in confirming the diagnosis, suggesting the presence of underlying heart disease, and identifying the location of the VT circuit 6.
- Determinants of hemodynamic instability in VT include old age, low ejection fraction, and polymorphic pattern of VT 3.