Etiology of Ventricular Tachycardia (VT)

Introduction

Ventricular tachycardia (VT) is a potentially life-threatening arrhythmia that originates in the ventricles. It is defined as a series of three or more consecutive ventricular beats at a rate of more than 100 beats per minute. The underlying causes of VT can be broadly categorized into structural heart diseases, non-structural causes, and electrolyte/metabolic imbalances.

Causes of Ventricular Tachycardia

1. Structural Heart Disease

• Ischemic heart disease (IHD): The most common cause of VT, often due to previous myocardial infarction, leading to scar formation and reentry circuits.
• Cardiomyopathies: Includes hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC).
• Valvular heart disease: Aortic stenosis, mitral valve prolapse, and other valvular pathologies can predispose to VT.
• Congenital heart disease: Patients with repaired congenital defects, such as Tetralogy of Fallot, have an increased risk of VT.

2. Non-Structural Causes

• Primary electrical abnormalities:
  • Long QT syndrome (LQTS)
  • Brugada syndrome
  • Catecholaminergic polymorphic VT (CPVT)
  • Idiopathic VT (e.g., right ventricular outflow tract VT)
• Drug-induced VT: Certain medications, such as antiarrhythmic drugs, antidepressants, and QT-prolonging agents, can trigger VT.

3. Electrolyte and Metabolic Imbalances

• Low potassium (hypokalemia) or magnesium (hypomagnesemia) can increase the risk of VT.
• Acidosis and ischemia-related metabolic disturbances contribute to arrhythmogenesis.

Conclusion

Understanding the etiology of VT is crucial for effective management and treatment. A thorough evaluation, including electrocardiography (ECG), imaging studies, and genetic testing in select cases, helps determine the underlying cause and guide therapy.

Source recommendations

1. American Heart Association Guidelines

1. https://professional.heart.org/en/guidelines-and-statements
2. https://www.heart.org/
3. https://professional.heart.org/en/guidelines-statements
4. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines
5. https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults

2. European Society of Cardiology Guidelines

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines
2. https://academic.oup.com/eurheartj/article/42/34/3227/6358713
3. https://www.escardio.org/Guidelines
4. https://academic.oup.com/eurheartj/article/44/39/4043/7238227
5. https://www.escardio.org/