Ventricular fibrillation

Question 1

Define ventricular fibrillation

Answer 1

Irregular broad-complex tachycardia that can cause cardiac arrest & sudden cardiac death

Question 2

Aetiology of ventricular fibrillation

2

Answer 2

Ventricular fibres contract randomly causing complete failure of ventricular function
Most cases occur in patient w/ underlying heart disease

Question 3

Risk factors for ventricular fibrillation

5

Answer 3

Coronary artery disease
AF
Hypoxia
Ischaemia
Pre-excitation syndrome

Question 4

Epidemiology of ventricular fibrillation

prevalence, group

Answer 4

MOST COMMON arrhythmia identified in cardiac arrest patients

Incidence of VF parallels incidence of ischaemic heart disease

Question 5

Presenting symptoms & signs of ventricular fibrillation

3 history +6 conditions

Answer 5

History of:
Chest pain
Fatigue
Palpitations

May be known pre-existing conditions:
Coronary artery disease
Cardiomyopathy
Valvular heart disease
Long QT syndrome 
Wolff-Parkinson-White syndrome
Brugada syndrome

Question 6

Investigations for ventricular fibrillation

6

Answer 6

ECG

Cardiac enzymes

Electrolytes

Drug levels & toxicology screen

TFTs

Coronary angiography

Question 7

Investigations for ventricular fibrillation - cardiac enzymes

Answer 7

e.g. troponins (recent ischaemic event)

Question 8

Investigations for ventricular fibrillation - electrolytes

Answer 8

Derangement —> arrhythmias

Question 9

Investigations for ventricular fibrillation - drug levels & toxicology screen

Answer 9

Anti-arrhythmics can cause arrhythmia themselves, or recreational drugs (e.g. cocaine)

Question 10

Investigations for ventricular fibrillation - TFTs

Answer 10

Hyperthyroidism —> tachycardia

Question 11

Investigations for ventricular fibrillation - coronary angiography

Answer 11

If patient survives VF, to check integrity of coronary arteries

Question 12

Management of ventricular fibrillation

5

Answer 12

Requires urgent defibrillation & cardioversion
Patients who survive need full assessment of left ventricular function, myocardial perfusion & electrophysiological stability
Most survivors will need an implantable cardioverter defibrillator (ICD)
Empirical β-blockers
Some patients may be treated w/ radiofrequency ablation (RFA)

Question 13

Complications of ventricular fibrillation

6

Answer 13

Ischaemic brain injury due to loss of cardiac output 
Myocardial injury
Post-defibrillation arrhythmias
Aspiration pneumonia 
Skin burns
Death

Question 14

Prognosis for ventricular fibrillation

3

Answer 14

Depends on time between onset of VF & medical intervention
Early defibrillation is essential (ideally 4-6 mins)
Anoxic encephalopathy is major outcome of VF