Causes of Ventricular Fibrillation (VF)

Introduction

Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia that leads to sudden cardiac arrest if not treated immediately. It occurs when the heart's electrical signals become chaotic, causing the ventricles to quiver instead of contracting properly. This results in the heart's inability to pump blood effectively, leading to loss of consciousness and death if untreated.

Main Causes of VF

1. Coronary Artery Disease (CAD) and Myocardial Infarction

• The most common underlying cause of VF is ischemic heart disease.
• When a heart attack (myocardial infarction) occurs, the lack of blood supply can cause scar tissue, which may lead to electrical instability and VF.

2. Cardiomyopathies

• Dilated cardiomyopathy: The heart muscle becomes weak, leading to arrhythmias.
• Hypertrophic cardiomyopathy (HCM): Thickened heart muscle increases the risk of abnormal heart rhythms.
• Arrhythmogenic right ventricular cardiomyopathy (ARVC): A genetic disease that disrupts heart muscle structure and increases VF risk.

3. Electrolyte Imbalances

• Potassium abnormalities (hypokalemia, hyperkalemia) can trigger dangerous arrhythmias.
• Calcium and magnesium imbalances also increase the risk.

4. Electrical Abnormalities and Channelopathies

• Long QT Syndrome (LQTS): A condition that prolongs the heart’s electrical recovery time.
• Brugada Syndrome: A genetic disorder that affects sodium channels and predisposes to VF.
• Wolff-Parkinson-White (WPW) Syndrome: An extra electrical pathway in the heart that can lead to dangerous arrhythmias.

5. Severe Heart Failure

• A weakened heart with impaired pumping ability increases the likelihood of VF.

6. Drug Toxicity and Substance Abuse

• Certain medications, such as antiarrhythmic drugs, tricyclic antidepressants, and stimulants, can trigger VF.
• Cocaine and amphetamines increase adrenergic activity, raising VF risk.

7. Electrical Shock or Trauma

• High-voltage electrical injuries can cause chaotic electrical impulses.
• Blunt chest trauma (commotio cordis), especially in young athletes, may trigger VF.

Importance of Immediate Intervention

VF requires immediate defibrillation (using an automated external defibrillator, AED) and cardiopulmonary resuscitation (CPR) to restore normal heart rhythm. Identifying and addressing underlying risk factors is critical for preventing VF episodes.

Conclusion

Ventricular fibrillation is a serious, often fatal condition if not treated promptly. Understanding its causes helps in prevention and early intervention, particularly in high-risk individuals.

Source recommendations

1. American Heart Association Guidelines on Sudden Cardiac Arrest

1. https://www.heart.org/en/health-topics/cardiac-arrest
2. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
3. https://www.heart.org/en/health-topics/heart-attack/about-heart-attacks/heart-attack-or-sudden-cardiac-arrest-how-are-they-different
4. https://cpr.heart.org/en/resources/cpr-facts-and-stats
5. https://www.heart.org/en/health-topics/heart-attack/warning-signs-of-a-heart-attack

2. European Society of Cardiology Guidelines on Ventricular Arrhythmias and 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://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
4. https://pubmed.ncbi.nlm.nih.gov/36017572/
5. https://www.sciencedirect.com/science/article/pii/S2405500X22010945