Ventricular Fibrilation

Question 1

What is the definition of ventricular fibrilation?

Answer 1

An irregular broad-complex tachycardia that can cause cardiac arrest and sudden cardiac death.

Question 2

What is the aetiology of ventricular fibrilation?

Answer 2

The ventricular fibres contract randomly causing complete failure of ventricular function

Most cases occur in patients with underlying heart disease

Question 3

What are the risk factors associated with ventricular fibrilation?

Answer 3

Coronary artery disease

AF

Hypoxia

Ischaemia

Pre-excitation syndrome

Question 4

What is the epidemiology of ventricular fibrilation?

Answer 4

The MOST COMMON arrhythmia identified in cardiac arrest patients

Incidence of VF parallels the incidence of ischaemic heart disease

Question 5

What are the signs and symptoms of ventricular fibrilation?

Answer 5

History of:

• Chest pain
• Fatigue
• Palpitations

There may be known pre-existing conditions:

• Coronary artery disease
• Cardiomyopathy
• Valvular heart disease
• Long QT syndrome
• Wolff-Parkinson-White syndrome
• Brugada syndrome

Question 6

What are the appropriate investigations for ventricular fibrilation?

Answer 6

ECG***

Cardiac enzymes (e.g. troponins) - check for recent ischaemic event

Electrolytes - derangement can cause arrhythmias, including VF

Drug levels and toxicology screen - anti-arrhythmics can (ironically) cause arrhythmia, as can various recreational drugs (e.g. cocaine)

TFTs - hyperthyroidism can cause tachyarrhythmias

Coronary angiography - if patient survives VF, to check the integrity of coronary arteries

Question 7

What is the management plan for ventricular fibrilation?

Answer 7

VF requires urgent defibrillation and cardioversion

Patients who survive need full assessment of left ventricular function, myocardial perfusion and electrophysiological stability

Most survivors will need an implantable cardioverter defibrillator (ICD)

Empirical beta-blockers

Some patients may be treated with radiofrequency ablation (RFA)

Question 8

What are the possible complications of ventricular fibrilation?

Answer 8

Ischaemic brain injury due to loss of cardiac output

Myocardial injury

Post-defibrillation arrhythmias

Aspiration pneumonia

Skin burns

Death

Question 9

What is the prognosis for patients with ventricular fibrilation?

Answer 9

Depends on the time between onset of VF and medical intervention

Early defibrillation is essential (ideally within 4-6 mins)

Anoxic encephalopathy is a major outcome of VF