Ventricular Fibrillation

Question 1

Define

Answer 1

Broad complex tachycardia
↘ ECG shows rate of >100 bpm
↘ QRS complex duration >120 ms
(>3 small squares)
No clear QRS complexes
*Cause of cardiac arrest and sudden cardiac death
The ventricular muscle fibres contract randomly causing a complete failure of ventricular function

Question 2

Causes

Answer 2

Most cases of ventricular fibrillation occur in patients with pre- existing known heart disease

Question 3

Symptoms

Answer 3

↘ CP, fatigue, palpitations

Question 4

Investigations

Answer 4

Cardiac enzymes (CK, troponin)
U&Es to check for metabolic disturbances
Toxicology screen
TFTs (hyperthyroidism cause)
CXR: signs of left heart failure, pulmonary hypertension. Echocardiography: underlying structural abnormalities and cardiac dysfunction

Question 5

Management

Answer 5

Use a synchronised DC shock ±Adrenaline
Treat any MI, HF, electrolyte disturbances Consider β blockers
Most survivors should be treated with an ICD (implantable cardiac defibrillator)

Question 6

Complications

Answer 6

NS ischaemic injury, myocardial injury, death

Question 7

Prognosis

Answer 7

prognosis for survivors of VF strongly depends on the time elapsed between onset and medical intervention
Prognosis is poor without intervention by 4-6 minutes after onset of VF
Early defibrillation often makes the difference between long-term disability and functional recovery

Question 8

Risk factors

Answer 8

commonly associated with coronary artery disease
May be due to an acute MI or ischemia, or a chronic infarction scar

Can be due to: antiarrhythmic drugs; hypoxia; ischaemia; AF; pre- excitation syndrome; electric shock administration

Question 9

Epidemiology

Answer 9

Most commonly identified arrhythmia in cardiac arrest pts Peak age 45 - 75 years