Arrhythmias happen when the electrical signals that your heart uses to beat don’t start in the right place or don’t move across your heart properly. This can alter your heart’s rhythm.
Most arrhythmias that come from the top of your heart (supraventricular or atrial arrhythmias) can cause symptoms but tend to be less serious. However, arrhythmias that arise from your ventricles (ventricular arrhythmias) can cause severe symptoms and can sometimes be fatal.
Atrial fibrillation is a common arrhythmia. It happens when the electrical impulses in your atria become disorganised and overrides your heart’s normal rate and rhythm. This causes your atria to contract in an irregular manner. You may notice that your heartbeat feels uneven and it may be faster than usual.
Atrial fibrillation puts you at a greater risk of developing a blood clot in your heart, which could cause a stroke. Therefore, if you have atrial fibrillation, your doctor is likely to recommend you take medication to reduce your risk of stroke.
There are different types of supraventricular tachycardia (SVT). Most are caused by one or more extra electrical pathways in your heart, between the atria and the ventricles. This can make your heart beat very quickly, possibly 250 beats per minute or more. Attacks of SVT often come and go spontaneously (usually in minutes).
If you have ventricular tachycardia, the electrical impulses fire too quickly from your ventricles, causing blood to be pumped out faster than usual. This can make your blood pressure very low and put you at risk of having a cardiac arrest (your heart stops beating).
If the attack lasts for 30 seconds or more, it’s called sustained ventricular tachycardia. Most people with ventricular tachycardia have a significant heart problem. This condition can develop into ventricular fibrillation and cardiac arrest.
If you have ventricular fibrillation, electrical impulses start firing from multiple sites in your ventricles. This happens very rapidly and causes your heart’s ventricles to quiver rather than pump. This means your heart can’t beat properly and little or no blood will be pumped. Ventricular fibrillation happens in seven out of 10 people having a cardiac arrest.
If you have ventricular fibrillation, you’ll quickly lose consciousness. Cardiac arrests are fatal unless treated immediately. It’s vital to start emergency cardiopulmonary resuscitation (CPR) straight away.
If you have heart block, there’s a problem with 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 what type of heart block it is.
If you have tachy-brady syndrome, your sinoatrial node, which generates the electric pulses in your heart, doesn’t function properly. This is called sick sinus syndrome. It causes your heart to beat slowly and then fast due to an atrial arrhythmia. This can cause palpitations (heartbeats that suddenly become more noticeable) and blackouts.
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:
- palpitations – an unpleasant awareness of your heartbeat, often described as a thumping in your chest
- dizziness, light-headedness or feeling faint
- fainting or collapsing
- chest discomfort
These symptoms aren't always caused by arrhythmia but if you have them see your GP immediately. If you have chest pains and other signs of a heart attack, call an ambulance right away.
Your doctor will ask about your symptoms and examine you. They may refer you to a cardiologist (a doctor who specialises in identifying and treating conditions of the heart and blood vessels). Your may have one or more of the following tests.
- Blood tests. These can test for certain substances in your blood, such as potassium.
- Electrocardiogram (ECG). This records the electrical activity of your heart to see how well it’s working.
- 24-hour heart monitor (ambulatory ECG). This records the electrical activity of your heart over 24 hours or longer.
- Exercise ECG. This can check for other problems with your heart and may trigger abnormal heart rhythms.
- Electrophysiological study. This determines if you have any extra electrical pathways in your heart that are causing an abnormal heart rhythm.
- Echocardiogram. This uses ultrasound (sound waves) to look at your heart’s structure, valves and pumping action.
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. To reduce palpitations (an unpleasant awareness of your heartbeat), try to steer clear of anything that triggers your arrhythmia such as alcohol or caffeine. Keeping a diary can help you monitor this. 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 anticoagulant medicines. These are known as blood-thinning medicines, such as warfarin. They can reduce your risk of having a blood clot that could cause a stroke.
Some medicines are given to stop an arrhythmia, while others are used to prevent them occurring. The medicine you take and how long you need to take it for will depend on the type of arrhythmia you have.
If you need to have a procedure to correct your arrhythmia, the procedure you have will depend on your condition. Your doctor will advise you which procedure is most suitable for you and explain the risks and benefits. If you’re having any of these procedures you’ll be monitored carefully throughout.
A cardioversion may be carried out if you have atrial fibrillation. 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, so you’ll be asleep during the procedure. However, it can sometimes be done using only a sedative. The sedative helps relieve any anxiety you may have and helps you relax.
Your doctor may suggest fitting a pacemaker if you have heart block or sinus node disease. A pacemaker is a small device that’s 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 using local anaesthetic. This will block pain from your chest area. You’ll stay awake during the operation, but may have a sedative to help you relax.
Implantable cardioverter defibrillator
An implantable cardioverter defibrillator (ICD) is similar to a pacemaker. If your doctor thinks you may be at risk of ventricular arrhythmia, you may be fitted with an ICD. This can monitor your heart rhythm and will deliver a small electric shock to correct your heartbeat if it detects a problem. ICDs are usually fitted under local anaesthetic and sedation in the same way as a pacemaker.
Catheter ablation therapy
You may have this procedure for atrial fibrillation, supraventricular tachycardia or ventricular tachycardia. Your doctor will insert a thin tube, called a catheter, into your heart, via a large vein in your groin. Heat or freezing treatment is used destroy the area of your heart that’s causing the abnormal rhythm. This procedure is usually done under local anaesthesia, with sedation to help you relax. If you have atrial fibrillation, it’s possible that your doctor will use catheter ablation to destroy your AV node (see image). You’ll have a pacemaker or ICD fitted before or as part of the procedure.
Arrhythmia can be caused by a number of things, including:
- heart attack or heart failure
- heart valve disease
- thyroid problems, eg hyperthyroidism
- sleep apnoea – a condition that causes gaps in your breathing while sleeping
- electrolyte disorders – an imbalance of minerals in your body
- high blood pressure
- coronary heart disease
- Wolff-Parkinson-White syndrome – an extra electrical connection in the heart that can cause SVT
The risk of developing atrial fibrillation increases as you get older. You may also be more at risk if you’re pregnant, smoke, an alcoholic or if you’ve had heart surgery.
Some types of arrhythmia may be caused by particular triggers, such as alcohol, caffeine, smoking tobacco, stress and anxiety, exercise and certain medicines. See our FAQs for more information.
It may not be possible to find a cause for your arrhythmia. It’s important to remember that having arrhythmia doesn’t necessarily mean that you have a serious heart problem.
Sometimes my heart skips a beat and thumps. What is this and do I need treatment?
Sometimes it may feel as though your heart has missed a beat or thumped suddenly. This is likely to be an ectopic heartbeat. Ectopic beats don’t usually cause problems but occasionally, if they happen frequently, they can be a sign of a more serious condition.
Usually your heartbeat originates in the sinus node in your heart. An ectopic beat occurs when an extra beat starts somewhere else in your heart. This happens before the usual beat can come from the sinus node.
Ectopic beats are generally completely harmless and don’t usually need treatment. However, if you do find the ectopic beats worrying, you can be treated with medicine.
Ectopic heartbeats are very common and you may not notice if you have one. However, if you have any other symptoms, see your GP. Don’t delay in calling an ambulance if you have chest pain or other signs of a heart attack.
Very rarely, ectopic beats can be linked to an underlying problem such as:
- chronic obstructive pulmonary disease (COPD) – a long-term condition that causes breathing problems
- coronary heart disease
- structural problems with your heart
If your ectopic beats are very frequent, or if you have other signs of heart disease, your GP may refer you to a cardiologist. A cardiologist is a doctor who specialises in identifying and treating conditions of the heart and blood vessels.
I think my medicine is affecting my heart rate. Should I stop taking it?
No. Don’t stop taking a prescription medicine without speaking to your GP first. If you’re taking an over-the-counter medicine, ask your pharmacist for advice.
Everyone has some variation in their heartbeat and you may occasionally feel a palpitation. A palpitation is a sudden awareness of your heartbeat. This is often described as a thumping in your chest.
Arrhythmia is a disturbance of the usual electrical rhythm of your heart. Most people will have some arrhythmia, with a symptom of palpitation, at some point in their life.
Arrhythmias can be caused by taking certain prescription or over-the-counter medicines, such as:
- beta-blockers used to treat some heart conditions
- digoxin used to treat heart failure
- calcium-channel blockers mainly used to treat high blood pressure
- levothyroxine used to treat hypothyroidism
- inhaled bronchodilators used to treat asthma
Over-the-counter medicines that act as stimulants, including decongestants found in cough and cold medicines and some herbal and nutritional supplements can also cause palpitations.
Some illicit drugs can also cause palpitations and, sometimes, medicines that are prescribed to treat an arrhythmia can actually make it worse.
Always read the patient information leaflet that comes with your medicine. If you think your medicine is causing an arrhythmia or making it worse, speak to your GP or pharmacist for more advice.
Can I drive a car or motorcycle if I have an arrhythmia?
The rules about whether you can drive depend on the type of arrhythmia you have, how well it is controlled and the type of vehicle you drive.
You’ll probably be able to drive a car or motorcycle as long as you don’t have any symptoms that could distract you when driving. However, the cause of your arrhythmia must have been identified and your condition controlled for at least four weeks. You therefore need to speak with your doctor to check they agree your condition is controlled.
You mustn’t drive if your arrhythmia causes symptoms that could distract you or affect your ability, such as dizziness or breathlessness. See your doctor for advice as you may need to change your treatment.
If you have a procedure to treat your arrhythmia, you won’t be able to drive for some time, depending on the treatment you have. How long you have to stop driving for can range from a week to several months. It will also vary according to how severe your condition is and whether or not you have other conditions that may prevent you from driving. Not driving until it’s confirmed that your arrhythmia is under control means that you won’t be putting yourself or others in danger.
The rules about driving are different if you have an arrhythmia and drive a lorry or are responsible for passengers. For example, you’ll not be allowed to drive a lorry or bus if your heart function is below a certain level.
If you’re in any doubt about driving, always follow your doctor’s advice and the DVLA’s. Also contact your motor insurer so that you’re aware of their recommendations.
- Overview of arrhythmias. The Merck Manuals. www.merckmanuals.com, published October 2013
- Arrhythmia. National Institutes of Health. www.nhlbi.nih.gov, published July 2011
- Campbell NA. Biology. 4th ed. Menlo Park, California: The Benjamin/Cummings Publishing Company, Inc.; 1996
- Types of arrhythmia. Arrhythmia Alliance. www.heartrhythmcharity.org.uk, accessed 12 November 2014
- Atrial fibrillation (AF). The Merck Manuals. www.merckmanuals.com, published October 2013
- Map of Medicine. Atrial fibrillation. International View. London: Map of Medicine; 2013 (Issue 4)
- Ventricular tachycardia (VT). The Merck Manuals. www.merckmanuals.com, published September 2013
- Ventricular fibrillation (VF). The Merck Manuals. www.merckmanuals.com, published September 2013
- How can palpitations be prevented? National Institutes of Health. www.nhlbi.nih.gov, published July 2013
- Map of Medicine. Bradyarrhythmias. International View. London: Map of Medicine; 2011 (Issue 2)
- Map of Medicine. Tachyarrhythmias. International View. London: Map of Medicine; 2014 (Issue 4)
- Ectopic Supracentricular rhythms. The Merck Manuals. www.merckmanuals.com, published September 2013
- Raviele A, Giada F, Bergfeldt L, et al. Management of patients with palpitations: A position paper from the European Heart Rhythm Association. Europace 2011; 13(7):920–34.
- What causes palpitations? National Institutes of Health. www.nhlbi.nih.gov, published July 2011
- For medical practitioners. At a glance guide to the current medical standards of fitness to drive. Drivers Medical Group. www.dft.gov.uk/dvla, published May 2014
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