DC cardioversion

Question 1

Define cardioversion.

Answer 1

The delivery of energy that is synchronised to the QRS complex

Question 2

Define defibrillation.

Answer 2

Asynchronous delivery of a shock randomly during the cardiac cycle.

Question 3

How is DC cardioversion carried out?

Answer 3

• To prevent VTE anticoagulation is required for 3-4 weeks before and after cardioversion OR exclude thrombus by echo
• Sedation administered by anaesthetist e.g. propofol
• Monitoring set up for ECG, BP, O2, CO2 end tidal
• Remove oxygen delivery device during shock delivery in case of electrical arcing causing fire
• Anterior posterior pads are placed
• Shock is delivered

Question 4

What energy levels are used for DC cardioversion in different conditions?

Answer 4

AF - 120-200J
Atrial flutter - 50-100J
VT with pulse - 100J
VF or pulseless VT - 200-360J

In obese patients higher energy may be required.

Question 5

What are the complications of DC cardioversion?

Answer 5

• ECG changes
• Hypotension due to sedation +/- vasodilation
• Skin irritation
• Arrhythmias
• Thromboembolism