Arrhythmias
Atrial fibrillation AF
Atrial fibrillation, commonly known as AF, is a condition where the atria, or upper chambers of the heart, fire chaotic electrical impulses. This leads the muscle to quiver, or fibrillate, instead of beat, so the heartbeat becomes irregular and is often faster than normal. It is one of the most common heart rhythm issues and around 1.7 million people in the UK have been diagnosed with it.
What happens in the heart
Every heartbeat begins with an electrical signal. In a normal rhythm that signal starts in a small structure called the sinus node, often described as the heart's natural pacemaker. It travels through the upper chambers of the heart, the atria, and then passes to the lower chambers, the ventricles, which allows the heart to pump blood efficiently around the body.
In atrial fibrillation the electrical signals in the atria become disorganised. Instead of a single organised signal controlling the heartbeat, many rapid impulses occur at the same time, so the atria quiver rather than contract properly.
Because of this disruption the ventricles receive irregular signals and the overall heartbeat becomes uneven. Some people experience a rapid heart rate during episodes of atrial fibrillation, while others notice mainly the irregular rhythm. The condition can occur occasionally in short episodes, or it may become persistent over time.
The symptoms people notice
The symptoms of atrial fibrillation vary widely from one person to another. Some people are very aware of changes in their heartbeat, while others may not notice anything unusual at all.
Common symptoms include the following.
In some cases atrial fibrillation is discovered during a routine medical check, even when there are no symptoms. A significant proportion of cases go undiagnosed because the rhythm is often silent or intermittent. However it is found, proper assessment is important.
- Palpitations or a fluttering sensation in the chest
- A heartbeat that feels irregular or pounding
- Shortness of breath
- Dizziness or light-headedness
- Fatigue or reduced energy levels
- Reduced ability to exercise
Why atrial fibrillation matters
One of the reasons cardiologists pay close attention to atrial fibrillation is its link with stroke. When the atria do not contract effectively, blood is not pumped properly and can stagnate in the heart, which allows small clots to form.
If a clot travels from the heart to the brain it can block the blood supply and cause a stroke, and clots can also travel to other organs. Ischaemic stroke, the type caused by a clot blocking the blood supply, accounts for around 85% of strokes in the UK.
Untreated AF raises the risk of stroke significantly, and effective treatment is available once a diagnosis is in place. Blood thinning medication can help prevent clots forming and protect against stroke. Managing atrial fibrillation therefore involves more than simply controlling the heart rhythm. It also focuses on reducing long-term cardiovascular risk.
What causes atrial fibrillation
There are many possible causes of atrial fibrillation, and sometimes more than one factor is involved. Common contributors include the following.
Age also plays a role, as the likelihood of atrial fibrillation increases over time. In other cases atrial fibrillation occurs in people with otherwise healthy hearts, sometimes triggered by stress, illness or lifestyle factors.
Untreated sleep apnoea is a recognised risk factor for atrial fibrillation, as well as for high blood pressure and heart failure, so heavy snoring and poor sleep are worth mentioning at a consultation. Identifying the underlying cause helps guide treatment decisions.
- High blood pressure
- Coronary artery disease
- Heart valve problems
- Thyroid disorders
- Excess alcohol intake
How atrial fibrillation is diagnosed
Diagnosing atrial fibrillation involves recording the electrical activity of the heart. An electrocardiogram, or ECG, is the most common test used to confirm the diagnosis. It measures the heart's electrical signals and shows whether the rhythm is irregular.
If symptoms occur only occasionally, longer monitoring may be recommended. A Holter monitor is a prolonged ECG recording, worn for 24 hours or longer, which gives a fuller understanding of the heart rhythm during normal daily life. An echocardiogram may also be used to examine the structure and function of the heart. Once treatment has started, regular ECGs are conducted to make sure it is working as it should.
Wearable devices are now part of this picture too. Writing about wearable heart monitoring, Dr Jogiya has said that in his own clinical experience around one in five new AF diagnoses he makes in private practice now starts with a smartwatch alert. A smartwatch ECG is a single-lead trace, which is enough to flag AF reasonably well but not enough to diagnose more complex rhythm problems or to assess the heart's structure, so any alert still needs proper interpretation.
If a device flags AF or another rhythm abnormality, the advice is not to panic and not to dismiss it. Save the trace or take a screenshot, note when it happened and how you felt, and arrange to see your GP or a cardiologist.
How atrial fibrillation is treated
Treatment for AF usually begins with medication to control the heart rate and regulate heart function. Patients diagnosed with AF may often also be commenced on blood thinning medication to prevent the risks of stroke or other blood clot formations in the heart.
Other treatments can include DC cardioversion and ablation procedures, which aim to reset the heart to its natural rhythm. Catheter ablation targets the areas of heart tissue responsible for triggering the abnormal electrical signals. In some cases a pacemaker is implanted to regulate the heart rhythm at a set pace.
The most appropriate treatment plan depends on factors such as age, overall health, symptoms and other medical conditions, which is why Dr Jogiya discusses the options with each patient rather than applying a single approach to everyone.
Daily habits matter alongside medical treatment, and several lifestyle measures support heart rhythm health.
- Maintaining regular physical activity
- Managing stress levels
- Limiting alcohol intake
- Prioritising good sleep
- Monitoring blood pressure
When to seek help
Palpitations, breathlessness, dizziness or a heartbeat that feels irregular are all worth having assessed, even when they come and go. Because atrial fibrillation can be silent or intermittent, symptoms that seem mild still deserve a proper look.
Call 999 immediately if you or someone with you has chest pain or sudden severe breathlessness, collapses, or shows signs of a stroke such as the face dropping on one side, weakness in one arm or slurred speech. A stroke is a serious, life-threatening condition that requires immediate and urgent treatment to minimise damage to the brain.
For symptoms that are not an emergency, assessment usually starts with an ECG, with a longer recording where the rhythm comes and goes and an echocardiogram where the structure of the heart needs to be assessed. This page is general information about atrial fibrillation and is not individual medical advice, so please speak to your GP or a cardiologist about your own symptoms.
Where the figures on this page come from
Every figure above is quoted from one of these. This page is general information, not individual medical advice.
More in arrhythmias
Related conditions he treats.
- Atrial flutterAtrial flutter is a heart rhythm problem that affects the upper chambers of the heart, known as the atria. Instead of beating at a normal pace, the atria beat rapidly, but in a regular and organised pattern rather than a chaotic one. Because the chambers do not have enough time to fill properly, blood is not pumped efficiently from the top chambers to the bottom chambers, which is what leads to shortness of breath.
- Atrial tachycardiaAtrial tachycardia is a fast heart rhythm that starts in the atria, the two upper chambers of the heart. An electrical signal emerges from another section of the atria and causes a rapid repeating beat, which means the atria beat very fast. It is one form of supraventricular tachycardia, or SVT, and short bouts of it can be common.
- Bundle branch blockBundle branch block describes a block in the part of the heart's conduction system known as the bundle branches. These branches carry the electrical impulse from the AV node down to each ventricle, and when one of them is blocked the signal reaches one side of the heart before the other, so the two ventricles no longer contract in step. It is a pattern picked up on an ECG, and mostly it is something monitored rather than actively treated.
- First degree heart blockFirst degree heart block is common, and it can affect anyone at any age. It describes a delay in the electrical signal as it travels from the upper chambers of the heart to the lower chambers, rather than a true blockage. Every signal still gets through, which is why many people notice nothing at all and why the condition is usually diagnosed when testing is being done for something else.
- Second degree heart blockSecond degree heart block is a fault in the heart's electrical wiring, not a blockage in an artery. Some of the electrical signals travelling from the upper chambers of the heart fail to reach the lower chambers, so a heartbeat is occasionally missed. There are two types, known as Mobitz I and Mobitz II, and they are treated very differently.
- Sick sinus syndromeSick sinus syndrome, also called sinus node disease, is a condition where the sinus node, the small area of tissue that acts as the heart's own natural pacemaker, is not functioning properly. Sometimes the node will send an impulse as it should, and sometimes it may not fire an impulse at all, or the impulses may be out of sync. Some patients notice symptoms such as palpitations and shortness of breath, and because the node is unreliable rather than permanently stopped, those symptoms often come and go.
- Supraventricular tachycardiaSupraventricular tachycardia, usually shortened to SVT, is a fast heart rhythm that starts above the ventricles, in the upper part of the heart. Symptoms vary widely from one person to another, so some people are very aware of an episode while others barely notice one. Short bouts of SVT can be common, and can usually be treated very easily.
- Tachy brady syndromeTachy brady syndrome is a heart rhythm problem in which the heart rate increases and then decreases spontaneously, without any external influence. Instead of settling at a pace that matches what you are doing, the heart swings between periods of a slow rate and sudden bursts of a fast one. It is closely linked to sinus node disease, and it occurs mostly alongside atrial fibrillation.