Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT)

Introduction

Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT) are life-threatening heart rhythm disorders that require immediate medical attention. Both conditions originate in the ventricles, the lower chambers of the heart, and can lead to sudden cardiac arrest if not treated promptly.

What is Ventricular Tachycardia (VT)?

VT is a rapid heart rhythm that originates in the ventricles. It is defined as a sequence of three or more consecutive ventricular beats at a rate of 100 beats per minute or more. VT can be classified into:

• Sustained VT (lasting more than 30 seconds or requiring intervention due to symptoms like hypotension, chest pain, or syncope)
• Non-sustained VT (lasting less than 30 seconds and usually terminating spontaneously)

Causes of VT

• Coronary artery disease (especially post-myocardial infarction)
• Heart failure
• Cardiomyopathies (hypertrophic or dilated)
• Electrolyte imbalances (potassium, magnesium disturbances)
• Drug toxicity (e.g., digoxin, antiarrhythmics)

Symptoms of VT

• Palpitations
• Dizziness
• Shortness of breath
• Chest pain
• Syncope (fainting)

Treatment of VT

• Stable VT: Antiarrhythmic medications (e.g., amiodarone, lidocaine, procainamide)
• Unstable VT: Immediate electrical cardioversion
• Long-term management: Implantable cardioverter defibrillator (ICD), catheter ablation, beta-blockers

What is Ventricular Fibrillation (VF)?

VF is a chaotic and disorganized electrical activity of the ventricles, leading to no effective cardiac output. This results in circulatory collapse and sudden cardiac arrest if not treated immediately.

Causes of VF

• Acute myocardial infarction (heart attack)
• Severe electrolyte imbalances
• Cardiomyopathies
• Drug toxicity
• Brugada syndrome, Long QT syndrome

Symptoms of VF

• Sudden loss of consciousness
• No pulse
• No breathing
• Cardiac arrest

Treatment of VF

• Immediate defibrillation
• Cardiopulmonary resuscitation (CPR)
• Epinephrine and antiarrhythmic drugs (amiodarone, lidocaine)
• Preventive strategies: ICD implantation, risk factor control

Conclusion

Both VF and VT are serious conditions requiring immediate attention. VF is always a medical emergency requiring defibrillation, while VT can range from stable to life-threatening cases requiring cardioversion, medication, or device therapy. Early recognition and prompt treatment are essential to prevent sudden cardiac death.

Source recommendations

1. American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

1. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines
2. https://professional.heart.org/en/science-news/2020-aha-guidelines-for-cpr-and-ecc
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001194
4. https://pubmed.ncbi.nlm.nih.gov/33081530/
5. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000918

2. European Society of Cardiology (ESC) Guidelines for Management of Ventricular Arrhythmias and 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.ahajournals.org/doi/10.1161/CIR.0000000000000549
5. https://pubmed.ncbi.nlm.nih.gov/26320108/