Atrial fibrillation

What is atrial fibrillation?

Atrial fibrillation (also known as AF or Afib) is a heart condition that causes an irregular, often very fast heart rhythm in a part of your heart known as the atrium. It's the most common form of cardiac arrhythmia (abnormal heart rhythm), affecting more than two million people in the UK. 

It may cause your heart to beat up to 200 BPM in an irregular pattern, compared to a normal consistent heart rate at rest of between 60 - 100 BPM. 

The condition causes the atria (your heart's two upper chambers) to quiver or twitch, known as fibrillation, due to out-of-control electrical signals. These signals are sent to the heart's lower chambers (the ventricles) – which are responsible for pumping blood around your body – causing them to also beat rapidly. 

Atrial fibrillation isn't usually life-threatening but can lead to serious complications such as stroke or heart failure without diagnosis and treatment. 

How to check your own heartbeat

Palpitations causing a fast, irregular heartbeat is the main symptom of atrial fibrillation. You can test your heartbeat by taking your pulse in your neck:

1. Sit down for at least five minutes and avoid drinking caffeinated beverages beforehand to make sure you're taking a resting heart rate.
2. Place the index and middle finger of your right hand on the pulse in your neck, and count the number of beats in a 30-second period. 
3. Double this number to find out your BPM. 

A normal resting heart rate is between 60 and 100 BPM. If you have atrial fibrillation, your heart will often be beating at over 100 BPM. 

Atrial fibrillation is due to abnormal electrical impulses in your heart's upper chambers that affect its normal rhythm. It’s most often due to the effects of normal ageing on the heart and from high blood pressure. Other factors which are associated with AF include:

• Coronary artery disease
• Heart valve disease
• Heart failure
• Being overweight
• Heart problems you're born with, known as congenital heart defects
• Previous heart surgery
• Myocarditis (inflammation of your heart muscle)
• Cardiomyopathy (diseases of your heart muscle)
• An overactive thyroid gland
• Infections, particularly pneumonia
• Obstructive sleep apnoea
• Recent surgery
• Excess alcohol consumption
• A family history of AF

Atrial fibrillation is more common in older people because of the electrical changes that happen in the atria as we age, but also it’s more common to have other heart-related problems as we get older. 

Lifestyle factors including obesity, alcohol, stress, smoking and substance abuse can also play a part. 

You can still develop atrial fibrillation without any of these pre-existing conditions or risk factors. When a cause can't be identified, this is known as lone atrial fibrillation.

How is atrial fibrillation diagnosed?

You may be diagnosed with atrial fibrillation after experiencing symptoms and visiting a GP or cardiologist. It can also be caught during routine health check-ups or checks for other problems, and it’s increasingly common for people to self-diagnose using wearable gadgets such as ECG watches.

If you do have atrial fibrillation symptoms, a health professional will examine you – including checking your pulse – and ask questions about your symptoms and medical history. They may follow this up with various tests depending on their findings, including:

• Blood tests to check for other health conditions that may be affecting your heart such as an overactive thyroid gland
• An electrocardiogram (ECG), a quick test to measure the electrical activity of your heart at the time using sticky patches connected to your body and wires connected to a computer
• An ambulatory electrocardiogram, which is a portable ECG worn to monitor your heartbeat constantly for 24 hours or longer, as recommended by your consultant. A more discrete device known as a Zio patch can be worn instead for up to two weeks and let you go about your regular activities.
• An implantable loop recorder, a very small device placed under your skin to look for episodes of AF over as long as four years. This is often used to look for AF in young people who have had an unexplained stroke (called a cryptogenic stroke).
• An echocardiogram, an ultrasound scan to assess your heart's structure and function for damage.

There are several different treatments for atrial fibrillation if you receive a diagnosis. For some patients, treating the underlying cause (such as an overactive thyroid) is enough. However, most people do require treatment for atrial fibrillation itself. 

Your doctor will advise you on the best course of treatment for you depending on:

• Your type and cause of atrial fibrillation
• Your age (atrial fibrillation treatment for elderly people can sometimes differ from younger patients, for example) 
• Your general health including any other medical conditions you may have

The main aims of treatment are to to control your heart rate and rhythm, make you feel better and to reduce the risks of stroke and heart failure. Possible options include atrial fibrillation catheter ablation, medications, arrhythmia surgery and implantable devices such as pacemakers. 

Atrial fibrillation (Afib) medication

Medication for atrial fibrillation may include:

• Flecainide to help maintain normal heart rhythm
• Beta-blockers such as bisoprolol to slow the heart rate down and help maintain normal heart rhythm 
• Calcium channel blockers such as verapamil or diltiazem to reduce your heart rate in Afib 
• Digoxin to help lower your heart rate in Afib further 
• Amiodarone to help restore and maintain normal rhythm

If you're at risk of a stroke, your doctor will also prescribe an anticoagulant to help prevent your blood from clotting and causing a stroke, such as rivaroxaban, apixaban, edoxaban, dabigatran or sometimes warfarin. 

Possible side effects

Like most medications, some of these medicines can have side effects. 

• Anticoagulants can sometimes cause bleeding.
• Beta-blockers can cause tiredness, cold hands and feet, low blood pressure, low mood and impotence.
• Flecainide can make you feel sick and in rare cases causes heart rhythm disorders.
• Verapamil can cause constipation, low blood pressure and ankle swelling. 
• Amiodarone can cause thyroid derangement, liver function abnormality and lung scarring, and is rarely used for long-term treatment.

If you're worried about the possible side effects of any of these medications, speak to your cardiologist or GP for advice. 

Atrial fibrillation procedures

Electrical cardioversion

In some cases, a procedure known as electrical cardioversion (or DC Cardioversion, or DCCV) may be recommended to try and restore a normal heart rhythm. 

In cardioversion, large sticky pads will be placed on your front and back. These are then connected to a defibrillator machine, which gives your heart a small, controlled electric shock to make it beat normally again. This is done under a quick, light general anaesthetic (you will be asleep).

In people with implanted defibrillators, cardioversion can also be done using your device internally. A quick, light general anaesthetic is also used.

Catheter ablation

Catheter ablation is a type of atrial fibrillation surgery and is typically carried out under general anaesthetic. Small, flexible tubes are inserted into the veins at the top of your leg, and fine wires (catheters) are guided through the tubes into your heart. 

Areas of tissue in your heart which cause atrial fibrillation are destroyed using either radiofrequency energy or by freezing (cryo-ablation). This procedure corrects your heartbeat so that it beats regularly.

Pulmonary vein isolation

Pulmonary vein isolation is one type of AF ablation that uses hot or cold energy to create tiny scars in the upper left chamber of the heart and block irregular electrical signals. The upper left heart chamber is where the four lung veins connect, known as the pulmonary veins. 

Atrioventricular node ablation

This ablation procedure is used in people with permanent AF to help control heart rate. It uses heat energy to create a tiny scar and block the pathway between the upper and lower chambers of your heart - an area known as the atrioventricular node - stopping the fast, irregular signals associated with atrial fibrillation. It requires insertion of a permanent pacemaker first. 

Pulse field ablation

Pulse field ablation is a new ablation technique that uses electrical energy to target affected heart tissue with minimal damage to surrounding structures.  

Surgical AF ablation (including Surgical MAZE)

Surgical treatment for AF is sometimes offered, particularly when you need surgery to another part of your heart e.g. a heart valve. It’s also used when the atria are large and can be minimally invasive, known as a convergent hybrid ablation procedure. 

A surgical MAZE procedure creates multiple scars through heat, freezing or a scalpel to electrically break up the upper chambers of your heart to stop atrial fibrillation. This can also be carried out through a catheter approach. 

Atrial fibrillation devices

Pacemaker

If medication and other procedures are unsuccessful in treating your atrial fibrillation, then your doctor may suggest fitting a pacemaker so that you can have an AV node ablation procedure. 

Pacemakers are smaller than a matchbox and are usually fitted inside your chest below the collarbone. They work by sending out an electrical signal which stop the heart beating slowly.

Atrial fibrillation can cause serious health problems in some cases, particularly if left undiagnosed and untreated. If you have atrial fibrillation, you may be at greater risk of:

Stroke

An irregular rhythm in the upper chambers of the heart (the atria) can cause blood clots to form. In some cases, these clots travel from the heart to the brain, blocking blood flow and causing a stroke. 

If you have atrial fibrillation you are five times more likely to have a stroke than people without it, though your personal risk depends on a range of factors including your age and other health conditions. 

Heart failure

In rare cases, atrial fibrillation which isn't controlled can lead to heart failure. This is because the excess strain placed on your heart muscle over time causes it to weaken, until it's unable to pump sufficient blood around your body. 

Dementia

Recurrent strokes from AF and damage to the brain can cause dementia.

Death

AF increases the risk of dying, though there is increasing evidence that treatment, especially AF ablation, reduces this risk.

Can you prevent atrial fibrillation?

It's not always possible to prevent atrial fibrillation, particularly if it's due to normal ageing or caused by an underlying health problem. However, there are several steps you can take to reduce your risk including:

• Giving up smoking 
• Losing weight (if you are overweight)
• Stopping or reducing alcohol consumption
• Eating a healthy diet: a qualified nutritionist will be able to advise you on a heart-healthy diet (rich in fresh fruit, vegetables and pulses, and low in saturated fats)
• Getting plenty of exercise
• Avoiding excessive stress and anger, which are linked to heart rhythm problems
• Controlling your cholesterol levels and blood pressure (with regular checks and treatment if necessary)
• Getting good sleep (between seven to nine hours a night)

The more positive changes you can make, the more your heart and general health can improve.