Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT) on ECG

Introduction

Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT) are both life-threatening arrhythmias that originate in the ventricles. They can lead to sudden cardiac arrest if not treated promptly. Recognizing these arrhythmias on an electrocardiogram (ECG) is crucial for immediate intervention and patient survival.

Ventricular Tachycardia (VT)

Definition:

VT is defined as a rapid rhythm originating from the ventricles, typically at a rate of 100–250 beats per minute (bpm).

ECG Characteristics:

• Wide QRS complex (>120 ms)
• Regular rhythm (monomorphic VT) or irregular in polymorphic VT
• AV dissociation (atria and ventricles beating independently)
• Fusion and capture beats may be seen
• Extreme axis deviation in some cases

Clinical Importance:

• Sustained VT (>30 sec) can lead to hemodynamic instability and cardiac arrest.
• Non-sustained VT (<30 sec) may indicate underlying heart disease and risk of progression to VF.
• Common causes: myocardial infarction, structural heart disease, electrolyte imbalances, and drug toxicity.

Ventricular Fibrillation (VF)

Definition:

VF is a chaotic, disorganized electrical activity of the ventricles leading to a complete loss of cardiac output.

ECG Characteristics:

• Irregular, erratic waveform with no discernible P waves, QRS complexes, or T waves
• Amplitude varies, from coarse to fine VF, signifying worsening prognosis
• No organized ventricular activity

Clinical Importance:

• VF causes immediate cessation of effective cardiac output.
• Requires immediate defibrillation and advanced cardiac life support (ACLS) measures.
• Common causes: myocardial infarction, ischemia, electrolyte disturbances, cardiomyopathy, and electrical shock.

Management Overview

1. For VT:

   • Stable VT: Consider antiarrhythmic drugs such as amiodarone or lidocaine.
   • Unstable VT: Immediate synchronized cardioversion is required.
   • Recurrent VT: Patients may need implantable cardioverter-defibrillators (ICDs).

2. For VF:

   • Immediate Defibrillation: This is the only effective treatment.
   • CPR (Cardiopulmonary Resuscitation): While waiting for defibrillation.
   • Address underlying causes: Electrolyte correction, ischemia treatment, etc.

Conclusion

Recognizing VF and VT on ECG is critical for saving lives. Both arrhythmias are medical emergencies requiring rapid identification and treatment.

Guidelines for Further Reading

• American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
• European Society of Cardiology (ESC) Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of 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 the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

1. https://pubmed.ncbi.nlm.nih.gov/36017572/
2. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
3. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
4. https://pubmed.ncbi.nlm.nih.gov/26320108/
5. https://academic.oup.com/eurheartj/article/36/41/2793/2293363