Arrhythmia is a disturbance of your heart’s usual electrical rhythm. Arrhythmias can happen at any age and mostly they aren’t serious.
Your heart pumps oxygen-rich blood all around your body through a network of blood vessels (arteries) to tissues including organs, muscles and nerves.
The usual pattern of a heartbeat starts when an electrical impulse is produced by part of your heart called the sinus node. The impulse is conducted to the top chambers of your heart (the left atrium and right atrium). This causes them to contract, pushing your blood into two lower, larger chambers (the left and right ventricles). The electrical impulse is then transmitted to the ventricles causing them to contract. This pushes the blood out of your heart to your lungs and the rest of your body.
Your heart will usually beat between 60 and 100 times a minute when you’re resting. There are certain times when it may beat faster or slower than this, for example if you’re exercising or depending on how fit you are.
There are a number of different types of arrhythmia. Most arrhythmias that come from the top of your heart (supraventricular or atrial) can cause symptoms but tend to be less serious. Arrhythmias that arise from your ventricles (ventricular) can cause severe symptoms and can sometimes be fatal.
Atrial fibrillation is the most common type of arrhythmia and happens when the electrical impulses in your atria become disorganised, which overrides your heart’s normal rate and rhythm. This causes your atria to contract in an irregular manner or ‘fibrillate’. You may notice that your heartbeat feels uneven and it may be faster than usual. Attacks of atrial fibrillation can last from a few seconds to over a week, and can cause symptoms including:
Atrial fibrillation can potentially lead to a blood clot forming in your heart – this is because your blood isn’t able to flow through properly. If a clot forms, it may travel to your brain and cause a stroke.
There are different types of supraventricular tachycardia (SVT) and most are caused by one or more extra electrical pathways in your heart, between the atria and the ventricles. This allows electrical impulses to ‘short-circuit’ and re-enter your atria instead of going to your ventricles. This means that the impulses end up travelling around your heart in a circle.
SVT can make your heart beat very quickly, possibly 250 beats per minute or more. Attacks of SVT may only last for a few seconds but can last for several hours or, rarely, days.
In ventricular tachycardia, the electrical impulses fire too quickly from your ventricles, causing blood to be pumped out faster than usual. Your ventricles may not have enough time to fill up properly with blood and this can sometimes cause your heart to stop pumping blood around your body (cardiac arrest).
If the attack lasts for 30 seconds or more, it’s called sustained ventricular tachycardia. Ventricular tachycardia can progress to a condition called ventricular fibrillation.
In ventricular fibrillation, electrical impulses start firing from multiple sites in your ventricles, very rapidly and in an irregular rhythm. This means your heart can’t beat properly and little or no blood will be pumped. Ventricular fibrillation is a type of cardiac arrest, which can be fatal. You will lose consciousness and your pulse and breathing will stop. A cardiac arrest needs urgent medical treatment – it’s vital to get emergency cardiopulmonary resuscitation (CPR) straight away.
If you have heart block, it means there is a problem affecting how the electrical impulses are transmitted from your atria to your ventricles. There are different types of heart block – it can occur in your atrioventricular (AV) node or in the muscle fibres that lead into your ventricles. Your AV node is found between the upper and lower chambers of your heart. The symptoms of heart block vary and you may or may not need treatment depending on how severe they are.
In tachy-brady syndrome (also called sick sinus syndrome), your sinus node doesn’t function properly and causes your heart to beat slowly and then fast and abnormally. This can cause you to feel dizzy or collapse.
Your symptoms will depend on the type and severity of your arrhythmia. How often you get them will also vary, ranging from every day to very infrequently, once or twice a year for example. With some types of arrhythmia you may not get any symptoms, but general ones include:
These symptoms aren't always caused by arrhythmia but if you have them, see your GP.
An arrhythmia can be caused by a number of things. This includes certain conditions such as:
The risk of developing an arrhythmia increases as you get older, and you may also be more at risk if you’re pregnant or recently had heart surgery. Some types of arrhythmia may be caused by particular triggers, such as alcohol, caffeine, smoking tobacco or cannabis, and certain medicines. See our frequently asked questions for more information.
Often it may not be possible to find a cause for your arrhythmia. It’s important to remember that having an arrhythmia doesn’t necessarily mean that you have a serious heart problem.
Your doctor will ask about your symptoms and examine you. He or she may refer you to a cardiologist (a doctor who specialises in identifying and treating conditions of the heart and blood vessels).
Your doctor may do tests including:
Your treatment will depend on the type, cause and severity of the arrhythmia that you have.
Sometimes, such as with ectopic beats, you may not need any treatment because your arrhythmia is unlikely to cause serious problems. Try to steer clear of any triggers of your arrhythmia that you know about, such as alcohol or caffeine. Ask your GP for advice about exercising.
Your doctor may prescribe medicines to help control your heart rhythm. These can include medicines to slow down your heart rate, such as beta-blockers, or antiarrhythmic medicines, such as amiodarone and flecainide – these work in different ways to control your heartbeat.
If you have atrial fibrillation, you may be advised to take blood-thinning medicines, such as warfarin, to reduce your risk of blood clots forming.
If you need to have surgery, the exact procedure you have will depend on your condition. Your doctor will advise you which one is most suitable for you.
This may be carried out if you have atrial fibrillation. In this procedure, your doctor will apply a controlled electric shock to your chest from a machine called a defibrillator. This aims to help restore your heart to its usual rhythm. Cardioversion is usually done under general anaesthetic, which means you will be asleep during the procedure, but it can sometimes be done using only a sedative – this relieves anxiety and helps you to relax.
Your doctor ma suggest having a pacemaker if you have heart block or sinus node disease. A pacemaker is a small device, usually implanted under your skin in the upper part of your chest. Electrical signals are sent from the pacemaker to your heart to stimulate it to beat at a specific rate. Your doctor will usually fit your pacemaker under local anaesthesia – this will block pain from your chest area and you will stay awake during the operation.
You may have this procedure for atrial fibrillation, supraventricular tachycardia or ventricular tachycardia. In this procedure, your doctor identifies the abnormal areas in your heart and then inserts a catheter into your heart, via a large vein in your groin. Heat or freezing treatment is used destroy the area that is causing the abnormal rhythm. The procedure is usually done under local anaesthesia.
If you have atrial fibrillation, it’s possible that your doctor will use catheter ablation to destroy your AV node. You will probably have a pacemaker fitted before the procedure is carried out.
An implantable cardioverter defibrillator (ICD) is similar to a pacemaker. If your doctor thinks you may be at risk of a ventricular arrhythmia, you may be fitted with an ICD. This can monitor your heart rhythm and deliver a small electric shock to correct your heartbeat if it detects a problem. ICDs are usually fitted under local anaesthetic in the same way as a pacemaker.
Produced by Polly Kerr, Bupa Health Information Team, March 2013.
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For answers to frequently asked questions on this topic, see FAQs.
For sources and links to further information, see Resources.
This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.
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