Sustained Ventricular Tachycardia (VT)

Introduction

Sustained ventricular tachycardia (VT) is a life-threatening arrhythmia that originates in the ventricles and lasts more than 30 seconds or requires termination due to hemodynamic instability. This condition is associated with significant risks, including cardiac arrest, heart failure, and sudden cardiac death.

Causes of Sustained VT

Sustained VT is usually associated with underlying heart disease. The most common causes include:

• Ischemic Heart Disease: Myocardial infarction (heart attack) can lead to scarring in the heart, which serves as a substrate for VT.
• Cardiomyopathies: Conditions like dilated and hypertrophic cardiomyopathy increase the risk of arrhythmias.
• Congenital Heart Diseases: Structural heart problems from birth.
• Electrolyte Imbalances: Abnormal levels of potassium, magnesium, or calcium.
• Drug Toxicity: Some medications, including antiarrhythmic drugs, can provoke VT.

Symptoms of Sustained VT

Symptoms can vary depending on the severity and duration of VT, including: - Palpitations (rapid heartbeats) - Dizziness or fainting (syncope) - Chest pain - Shortness of breath - Sudden cardiac arrest in severe cases

Diagnosis

The diagnosis of sustained VT involves several steps: - Electrocardiogram (ECG): Key diagnostic tool showing sustained wide QRS complexes with a ventricular rate over 100 bpm. - Holter Monitoring: Continuous ECG recording for 24-48 hours. - Electrophysiology Study (EPS): Helps identify the specific origin of VT. - Echocardiography and Cardiac MRI: To assess structural heart abnormalities.

Treatment

Treatment depends on symptoms, underlying heart disease, and hemodynamic stability:

Emergency Management

• Hemodynamically unstable VT: Immediate synchronized cardioversion is required.
• Hemodynamically stable VT:
  • Intravenous antiarrhythmic drugs (e.g., amiodarone, lidocaine, procainamide).
  • Correction of possible electrolyte imbalances.

Long-Term Strategies

1. Medication:

   • Beta-blockers (e.g., metoprolol) for arrhythmia prevention.
   • Antiarrhythmic drugs (e.g., amiodarone, sotalol) in select cases.

2. Implantable Cardioverter-Defibrillator (ICD):

   • Recommended for high-risk patients to prevent sudden cardiac death.

3. Catheter Ablation:

   • In selected cases, ablation is performed to eliminate the ventricular arrhythmia source.

4. Lifestyle Modifications:

   • Treatment of underlying heart disease.
   • Avoidance of known triggers (e.g., drugs that prolong QT interval).

Conclusion

Sustained VT is a serious medical condition requiring rapid diagnosis and appropriate management to prevent life-threatening complications. Proper screening, treatment, and preventive strategies significantly improve outcomes.

Source recommendations

1. American Heart Association Guidelines on Ventricular Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
2. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
4. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation
5. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms

2. European Society of Cardiology Guidelines for the Management of Patients with Ventricular Arrhythmias

1. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
2. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
3. https://pubmed.ncbi.nlm.nih.gov/36017572/
4. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
5. https://pubmed.ncbi.nlm.nih.gov/26320108/