Ventricular Fibrillation

Question 1

What is VF? (2 things)

Answer 1

1. Life threatening arrhythmia
2. Disorganized + High Frequency Ventricular Contractions

Question 2

What does VF result in? (2 things)

Answer 2

1. Reduced CO
2. Haemodynamic collapse

Question 3

How does VF usually start off as?

Answer 3

VT w very irreg rhythm

Question 4

What are the causes of VF? (4 things)

Answer 4

1. Underlying CVS disease (CAD (most common) / MI / myocarditis / cardiomyopathy)
2. Congenital heart defects (pulmonary atresia)
3. Electrolyte abn (hypokalaemia / hyperkalaemia)
4. Electrophysiologic disorders (e.g Wolff-Parkison-White syndrome / Torsade de Pointes)

Question 5

How can VF cause death? (6 steps)

Answer 5

1. Re-entry of signal
2. Chaotic circular excitation of myocardium = VF
3. Simultaneous contractions @ multiple foci
4. Insufficient CO
5. Haemodynamic collapse
6. Loss of consciousness / Death

Question 6

How can signal re-entry in VF happen? (2 things)

Answer 6

1. Changes to conduction pathway (e.g unexcitable scar tissue bc MI)
2. Abn excitation pattern (e.g recovery period of myocardial cells longer than AP (long QT syndrome)

Question 7

What are the clinical features of VF? (5 things)

Answer 7

1. Fatigue / Dizziness
2. SOB
3. Chest Pain
4. Palpitations
5. Loss of consciousness / death (ultimately)

Question 8

What are the ECG findings of VF? (5 things)

Answer 8

1. Commonly preceded by VT
2. Arrhythmic, fibrillatory baseline
3. Usually 300+ bpm
4. Undistinguishable QRS complexes
5. No P waves

Question 9

How should underlying conditions of VF be evaluated for? (9 things)

Answer 9

1. ECG
2. Cardiac enzymes
3. Electrolytes
4. TSH
5. Drug levels + toxicology screen
6. ABG
7. Coronary angiography
8. Echo
9. Nuclear imaging

Question 10

What are the Resus management options for VF? (2 things)

Answer 10

1. Defibrillator + Adrenaline
2. If fails –> amiodarone / lidocaine

Question 11

What are the Post-resus management options for VF? (4 things)

Answer 11

1. Continue Resus antiarrythmatics (amiodarone / lidocaine)
2. Beta blockers
3. Treat underlying causes
4. Implantable Cardioverter Defibrillator (ICD) (if NO reversible cause / haemodynamically significant VF)