Rhythm Restoration
Electrical Cardioversion
Electrical cardioversion is a planned procedure that uses a carefully timed electrical impulse to return an abnormal heart rhythm to a normal one. It is used in selected patients after assessment.
On this page
Understanding the treatment
What Is Electrical Cardioversion?
Electrical cardioversion is a procedure in which a brief electrical impulse is delivered through the chest, timed to the heart’s own electrical activity. The aim is to stop an abnormal, usually fast, rhythm so that the heart’s normal rhythm can take over again.
It is usually planned in advance and performed under short sedation or anaesthesia, so patients are not aware of the impulse.
Conceptual illustration of rhythm before and after cardioversion
Two different things
Cardioversion vs Defibrillation
Planned
Synchronised cardioversion
Timed to the heartbeat and used to treat certain organised fast rhythms, usually in a planned and controlled setting.
Performed after assessment and preparation.
Emergency
Defibrillation
Used in life-threatening situations such as cardiac arrest, when the heart has lost an organised rhythm.
Not timed to the heartbeat and not a planned procedure.
Clinical context
When It May Be Considered
Cardioversion may be considered in selected patients whose rhythm problem is causing symptoms, or where restoring a normal rhythm is part of the treatment plan. Whether it is suitable depends on the rhythm, how long it has been present, the symptoms and the overall health of the patient.
In selected patients, to restore a normal rhythm. See the atrial fibrillation page.
Cardioversion is one of the options for selected patients.
Other fast rhythms
Some other tachyarrhythmias may be treated this way when the doctor considers it appropriate.
Before deciding
Rhythm Assessment
The rhythm is confirmed before any decision is made. An ECG records the rhythm at the time of the visit, and ambulatory monitoring may show how the rhythm behaves over time.
The doctor also considers the symptoms, heart structure, other health conditions and previous treatment.
Safety
Anticoagulation Considerations
When the heart has been in an irregular rhythm, restoring a normal rhythm can carry a risk of clot-related problems such as stroke. For this reason, your doctor will consider your clot risk before and after cardioversion.
Whether and how blood-thinning treatment or additional imaging is needed is decided for each patient. Medication plans are always given by your own doctor and should not be changed on your own.
General preparation
Preparation
The care team will explain what to expect before the day of the procedure. Instructions differ between patients and centres, so follow the guidance you are given.
Instructions
You are told about fasting and about your usual medicines.
Tests
Recent tests may be reviewed or repeated.
Questions
You can ask about risks, alternatives and what recovery will involve.
The procedure
How the Procedure Is Done
Cardioversion is usually carried out as a day-case procedure. The steps below describe the general outline.
Monitoring
Heart rhythm and vital signs are monitored.
Sedation
Short sedation or anaesthesia is given.
Electrodes
Pads are placed on the chest.
Synchronised impulse
A timed impulse is delivered.
Rhythm check
The rhythm is checked on the monitor.
Recovery
After the Procedure
Patients are observed until the sedation wears off, and the rhythm is checked again. Many people can go home the same day, usually with someone to accompany them, as advised by the care team.
The skin under the pads may look pink or feel sore for a short time. You will be told what to do about blood-thinning treatment and which symptoms need medical advice. Contact your care team if you have chest pain, breathlessness, fainting or any new neurological symptom.
The wider picture
Cardioversion and Atrial Fibrillation
In atrial fibrillation, cardioversion can restore a normal rhythm, but it does not remove the underlying tendency to develop the rhythm problem. For this reason, it is often part of a broader plan that may include medicines, risk-factor management or catheter ablation.
Looking ahead
Recurrence and Follow-up
The abnormal rhythm may return after cardioversion in some patients. This does not mean the treatment has failed; it gives useful information for planning the next steps.
Follow-up may include an ECG, ambulatory monitoring and a review of symptoms and treatment. If the rhythm returns, your doctor will discuss the options with you.
Questions
Frequently Asked Questions
What is electrical cardioversion?
A planned procedure in which a timed electrical impulse is used to return an abnormal heart rhythm to a normal one.
Is it the same as defibrillation?
No. Cardioversion is planned and timed to the heartbeat. Defibrillation is used in emergencies.
Will I feel the impulse?
Sedation or anaesthesia is used so that you are not aware of the impulse.
Do I need to stay in hospital?
Usually it is a day-case procedure, but this depends on the patient.
Why is blood-thinning treatment discussed?
Because restoring the rhythm can carry a clot-related risk. Your doctor will explain what applies to you.
Can the rhythm come back?
It can. Follow-up helps to decide the next steps.
Does it cure atrial fibrillation?
It can restore a normal rhythm but does not remove the underlying tendency to the condition.
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