Polymorphic Ventricular Tachycardia (PVT)

Introduction

Polymorphic Ventricular Tachycardia (PVT) is a dangerous type of ventricular arrhythmia characterized by rapid and irregular QRS complex morphology. Unlike monomorphic ventricular tachycardia (VT), where the QRS complexes are uniform, PVT shows varying shapes and amplitudes.

Causes and Risk Factors

PVT can be associated with various conditions, including: - Long QT Syndrome (LQTS): A genetic or acquired disorder that prolongs repolarization. - Short QT Syndrome: A rare hereditary condition affecting cardiac repolarization. - Ischemic Heart Disease: Myocardial infarction can lead to arrhythmias. - Electrolyte Imbalances: Low potassium (hypokalemia) and magnesium (hypomagnesemia) increase risk. - Drug-Induced QT Prolongation: Medications such as antiarrhythmics, antipsychotics, and antibiotics. - Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): A genetic disorder triggered by stress or exercise.

Symptoms

• Palpitations
• Dizziness
• Syncope (fainting)
• Sudden Cardiac Arrest in severe cases

Diagnosis

• Electrocardiography (ECG): A changing QRS morphology is typical.
• Electrolyte Testing: Check potassium, calcium, and magnesium levels.
• Genetic Testing: Especially in young patients with unexplained PVT.
• Holter Monitoring: Continuous ECG recording for detection of intermittent episodes.

Treatment

• Acute Management:
  • Immediate Defibrillation if unstable.
  • Intravenous Magnesium Sulfate for torsades de pointes.
  • Beta-blockers and sodium channel blockers in congenital cases.
• Long-Term Management:
  • Implantable Cardioverter-Defibrillator (ICD) for high-risk individuals.
  • Medications such as beta-blockers (propranolol, nadolol) in CPVT.
  • Lifestyle Modifications: Avoid QT-prolonging drugs and electrolyte abnormalities.
  • Catheter Ablation: In some cases to eliminate arrhythmogenic foci.

Conclusion

PVT is a serious arrhythmia requiring immediate recognition and treatment. Identifying underlying causes and appropriately managing risks is crucial to prevent life-threatening complications.

Source recommendations

1. European Society of Cardiology (ESC) Guidelines on Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
2. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
3. https://pubmed.ncbi.nlm.nih.gov/36017572/
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2022/09/02/14/23/2022-ESC-Guidelines-for-VAs-ESC-2022
5. https://pubmed.ncbi.nlm.nih.gov/26320108/

2. American Heart Association (AHA) Guidelines on the Management of Ventricular Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
2. https://pubmed.ncbi.nlm.nih.gov/29084733/
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
4. https://pubmed.ncbi.nlm.nih.gov/29097320/
5. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation