Cardioversion
Cardioversion—also known as external cardioversion—is a medical procedure used to restore a normal heart rhythm in patients with abnormal heartbeats, particularly atrial fibrillation (AF) or atrial flutter. These common arrhythmias cause the heart to beat too fast or irregularly, reducing its ability to pump blood efficiently.
There are two main types of cardioversion:
- Electrical Cardioversion: A defibrillator is used to deliver controlled, low-energy electrical shocks to the chest, typically producing immediate results.
Chemical Cardioversion: Medications are used to restore the heart’s rhythm gradually, without the need for electrical shocks.
What does it do?
The goal of cardioversion is to return the heart to a normal sinus rhythm, allowing the upper (atria) and lower (ventricles) chambers of the heart to beat in a coordinated and efficient manner.
In conditions like AF or atrial flutter, the atria beat too quickly or erratically, which may result in:
- Chest discomfort or palpitations
- Shortness of breath
- Extreme fatigue
- Reduced blood flow to the body
Cardioversion helps reset the heart’s electrical system, improving blood circulation and relieving these symptoms.
How does it work?
- Electrical Cardioversion:
Electrodes are placed on your chest and connected to a defibrillator. A brief, controlled electrical shock is delivered to the heart to restore a normal rhythm. Most patients respond immediately, although it may take days or weeks for some to fully stabilise.
Chemical Cardioversion:
Anti-arrhythmic medications are administered—usually orally or via IV—to gradually slow and correct the heart’s rhythm. These drugs relax the heart muscle, ease electrical strain, and restore rhythm over time.
Why is it performed?
Cardioversion is typically recommended when:
- Medications have not been successful in correcting the rhythm
- You are experiencing symptoms due to AF or atrial flutter
- A normal rhythm is needed to improve heart efficiency or reduce stroke risk
Your doctor may suggest cardioversion as a first-line treatment or after other methods have been tried.
The procedure
- Performed in a hospital setting
- You will receive short-acting anaesthesia so that you remain asleep and feel no pain
- Electrodes are applied to your chest and connected to a defibrillator
- One or more low-energy shocks are delivered to correct the rhythm
- Your heart will be monitored throughout and for several hours afterward
Chemical cardioversion may be done using oral or intravenous medications, depending on your condition.
Recovery
Most patients can return home the same day and resume regular activities within a few days. Your medical team will provide recovery instructions and follow-up care.
If your irregular rhythm returns, cardioversion can be repeated, or your doctor may explore alternative treatments, such as catheter ablation or medication adjustments.