Cardioversion

Cardioversion is a procedure that helps to get your heart’s rhythm back to normal if it’s beating unevenly or too fast. Cardioversion can treat abnormal heartbeats (arrhythmias) or atrial fibrillation (an irregular and abnormally fast heartbeat). Here we look at a type of cardioversion called electrical or direct-current (DC) cardioversion.

About cardioversion

An abnormal heart rhythm is called an arrhythmia. It happens when the normal electrical signals in your heart don’t work properly and your heart beats too fast, too slow or irregularly.

Cardioversion involves shocking your heart if it’s beating too fast. To get your heart’s rhythm back to normal, an electric shock is delivered to your heart from a machine called a defibrillator. For this procedure, you’ll be asleep with a general anaesthetic or heavily sedated.

A cardioversion procedure can treat different types of arrhythmia including:

• atrial fibrillation
• atrial flutter
• ventricular tachycardia

Cardioversion usually works well, but it isn’t suitable for everyone. Ask your doctor if it’s an option for you. Whether or not it’s right for you may depend on:

• how long you’ve had the arrhythmia
• your symptoms
• your medical history

Preparation for cardioversion

Preparation for an urgent cardioversion

If you need to have cardioversion urgently, there may be nothing you need to do to get ready for it.

A doctor may give you a medicine (called an anticoagulant) that stops your blood clotting. You’re likely to have this through a drip into a vein in your hand or arm.

You may also have a scan called a transoesophageal echocardiogram to check for blood clots in your heart. An ultrasound sensor is put into your oesophagus (gullet) to look at your heart. Your oesophagus is the pipe that goes from your mouth to your stomach. You’ll have cardioversion as soon as your doctor has checked it’s safe to go ahead.

Preparation for a planned cardioversion

If your cardioversion is planned, there’ll be time for you to take any medicines your doctor prescribes before the procedure. They may prescribe:

• oral anticoagulant medicines – these are tablets that help stop your blood clotting
• anti-arrhythmic medicines – these help to control your heart’s rhythm, which means the cardioversion is more likely to work

You may need to take these medicines for several weeks before and after your cardioversion. You will have some tests in hospital before cardioversion. These will help your doctor decide if cardioversion is right for you. You will have an electrocardiogram (ECG), which measures the electrical activity in your heart and its rhythm. You may also have the following tests.

• Blood tests – these will check for lots of things, including how well your blood clots.
• An echocardiogram – this is an ultrasound scan of your heart. It provides a clear image of your heart muscles and valves, and shows how well your heart is working.
• A transoesophageal echocardiogram – this is a scan to check for blood clots in your heart.

A planned cardioversion is done as a day-case procedure. This means you’ll probably be able to go home on the same day, but it’s possible you may need to stay in hospital overnight. You usually can’t eat or drink on the day of your cardioversion, but follow your doctor’s advice.

Don’t put any powders, lotions or creams on your chest for 24 hours before your cardioversion. These can cause problems with the paddles used for passing the electrical current. If you have any chest hair where the paddles will go, a doctor or nurse may shave it off. You’ll be asked to remove any jewellery before your cardioversion.

Your doctor will discuss with you what will happen before, during and after your procedure. If you’re unsure about anything, don’t be afraid to ask. No question is too small. It’s important that you feel fully informed, so you feel happy to give your consent for the procedure to go ahead.

Ask a friend or relative to drive you home and stay with you after your cardioversion.

Cardioversion procedure

Cardioversion usually takes up to 30 minutes. You’ll be given a sedative or a short-acting general anaesthetic so you’ll be asleep during the procedure.

Your doctor will put two pads (electrodes) on the upper right and lower left of your chest. Sometimes the pads may be put on the front and back of your chest instead. These pads are linked to a defibrillator machine. They’ll give your heart a brief, controlled electric shock in time with the beat of your heart. The electric shock works across your whole heart at once to re-set your heart rate and rhythm back to normal.

Your doctor will monitor your heart rate and rhythm during the procedure. This means they can see straightaway whether the procedure has reset your heart to its normal rhythm. Your doctor may give you one or two more electric shocks to reset your heart if the first one doesn’t work properly.

Aftercare following cardioversion

When you wake up after cardioversion, you may feel tired or unsteady. You’ll need to rest for a few hours until the anaesthetic or sedation has worn off. Your hospital team will let you know when you can go home.

The doctors and nurses will use an ECG machine to monitor your heartbeat. Once they’re happy you’re recovering well and you feel ready, you can get out of bed and walk around.

You’ll probably be given a date for a follow-up appointment before you leave. Your doctor will usually prescribe anticoagulant and anti-arrhythmia medicines for you to take at home.

If you were given anticoagulants before your procedure to thin your blood, you need to continue taking them at home as well.

Arrange for someone to drive you home. General anaesthesia and sedation can make it harder to coordinate your movements and to think clearly. So, it’s a good idea to ask someone to stay with you for the first 24 hours. Don’t drive, look after children, cook, drink alcohol, operate machinery or sign legal documents during this time.

Recovery following cardioversion

Take it easy for a few days after your procedure. Your doctor will give you advice about what to do. If the paddles have made your skin a little sore (like you have sunburn), you may need to use some creams. Your doctor will usually tell you what to use. They’ll also give you advice about when you can go back to work and start exercising again.

It’s important to keep taking any medicines for as long as your doctor recommends. Anticoagulant medicines will lower your chances of getting a blood clot. You may also need to take anti-arrhythmic medicines – for example, amiodarone – for a while after your cardioversion. This will help to keep your heart rate stable. If you have any questions about your medicines or how to take them, ask a pharmacist.

You’ll have check-ups with your doctor after cardioversion. The first will be around three months after cardioversion.

Contact your GP if you notice any changes in your heartbeat or if your symptoms come back. If your abnormal heart rhythm comes back after you’ve had cardioversion, you may need more treatment. Your doctor may recommend you have cardioversion again. But usually after two or three cardioversions, your doctor may recommend that you have a different treatment, such as medicines or ablation.

Side-effects of cardioversion

Side-effects are unwanted, but mostly temporary, effects you may get after having a procedure. After cardioversion you may:

• notice your chest feels a bit sore where you had the shock
• have some burns on the skin on your chest
• have a headache or feel dizzy if your blood pressure dropped for a while during the procedure

Some of the medicines you’re given to take before or after your cardioversion can have some side-effects too. Ask your doctor about any risks or side-effects of medicines they recommend for you.

Complications of cardioversion

Cardioversion is usually a safe procedure, but sometimes it can cause complications.

In some people, cardioversion doesn’t work or their symptoms come back again. Cardioversion may cause other problems with your heart rhythm. You may need to take a medicine to treat this.

You may get a blood clot. Having a blood clot after cardioversion for some types of arrhythmia can make you more likely to have a stroke. But your doctor may prescribe anticoagulant medicines before and after your procedure to reduce the chances of this happening.

Alternatives to cardioversion

• This information is about electrical or DC cardioversion. Chemical (or pharmacological) cardioversion is when your doctor gives you medicines to bring back your regular heart rhythm rather than using electricity. Ask your doctor if this could be an option for you, and what it involves. A pharmacological cardioversion procedure should be the same as an electrical cardioversion procedure. Your doctor may suggest other treatments to help regulate your heart’s rate and rhythm. The best one for you will depend on the type of arrhythmia you have and your general health.
• Anti-arrhythmic medicines – you must take these tablets long-term to help control your heart’s rate and rhythm. Your doctor may also offer you anticoagulant medicines to prevent blood clots.
• Ablation – this procedure involves putting a thin tube through one of your veins (often in your groin) to reach into your heart. The area of your heart muscle that’s causing the abnormal heart rate is then heated or frozen to form a scar. This scar doesn’t conduct electricity, so it stops any abnormal electrical signals.
• Pacemaker – if you have this device fitted, it can regulate your heartbeat if you have a slow heart rhythm. It’s often an option if medicines haven’t worked for you.

Speak to your doctor about whether or not any of these treatment options are right for you.