Understanding Atrial Fibrillation: Symptoms, Causes, and Stroke Prevention

Atrial fibrillation (AF) is the most common heart rhythm disturbance (arrhythmia) in the UK. It occurs when the electrical impulses in the upper chambers of the heart (the atria) become disorganized and chaotic. Instead of the heart beating in a regular, coordinated fashion, the atria quiver or 'fibrillate'.

This irregular activity often causes the heart to beat faster than normal—sometimes significantly so. While AF itself is not usually life-threatening, it causes the blood to flow less efficiently through the heart. This can lead to the formation of blood clots, which is why AF is a major risk factor for strokes. According to the NHS, AF affects approximately 1.4 million people in the UK, particularly those over the age of 65.

Many individuals with atrial fibrillation do not experience any obvious symptoms. In these cases, the condition may only be discovered during a routine medical check-up. However, for those who do experience symptoms, the most common indicator is heart palpitations.

Palpitations can feel like:

• A racing or 'thumping' heart.
• A fluttering sensation in the chest.
• The feeling that the heart is skipping a beat or beating irregularly.

Other common symptoms of AF include persistent tiredness or lethargy, shortness of breath (especially during physical activity), feeling faint or lightheaded, and chest pain. Because these symptoms can mimic other health conditions, it is important to have an irregular pulse investigated by a healthcare professional.

The exact cause of AF isn't always clear, but it is often linked to other cardiovascular conditions that put strain on the heart. High blood pressure (hypertension) is one of the leading contributors to AF in the UK, as it causes the heart muscle to thicken and change shape over time.

Other common causes and risk factors include:

• Coronary heart disease or a history of heart attacks.
• Heart valve disease.
• An overactive thyroid gland (hyperthyroidism).
• Obesity and a sedentary lifestyle.
• Sleep apnoea.
• Excessive alcohol consumption or binge drinking (sometimes referred to as 'holiday heart syndrome').

In some cases, people develop AF without any identifiable underlying health issues; this is known as 'lone atrial fibrillation'.

The most serious complication of atrial fibrillation is an ischaemic stroke. When the heart does not pump effectively, blood can pool in the atria. This stagnant blood is more likely to form clots. If a clot is pumped out of the heart and travels to the brain, it can block an artery and cause a stroke.

Patients with AF are five times more likely to have a stroke than those without the condition. Furthermore, AF-related strokes are often more severe and carry a higher risk of long-term disability. This is why a central part of managing AF in the UK involves the use of anticoagulant medications (blood thinners) to reduce the risk of clot formation.

Diagnosing AF starts with a simple pulse check. If your pulse feels irregular or 'persistently erratic', a GP will usually refer you for an Electrocardiogram (ECG). An ECG records the electrical activity of your heart and is the definitive way to confirm an AF diagnosis.

Treatment focuses on two main goals: managing the heart rhythm and preventing strokes. Options include:

• Rate Control: Medications like beta-blockers or calcium channel blockers to slow the heart rate down to a normal level.
• Rhythm Control: Medications or procedures like cardioversion (a controlled electric shock) to restore the heart's normal sinus rhythm.
• Anticoagulation: Drugs such as warfarin or newer Direct Oral Anticoagulants (DOACs) like apixaban or rivaroxaban are prescribed to thin the blood.
• Catheter Ablation: A procedure where a small area of heart tissue causing the irregular signals is destroyed using radiofrequency energy.

While medical intervention is necessary, lifestyle changes play a significant role in managing AF and improving quality of life. Maintaining a healthy weight reduces the strain on the heart and has been shown to reduce the frequency of AF episodes. Reducing alcohol intake and quitting smoking are also highly recommended.

Many patients find that stress or high caffeine intake can trigger palpitations. Keeping a 'trigger diary' can help you identify factors that worsen your symptoms, allowing you to make informed adjustments to your daily routine alongside your clinical treatment plan.

If you have noticed that your heart rate feels irregular, even if you feel otherwise well, you should seek medical advice. An online GP can discuss your symptoms, review your medical history, and advise on whether you need a face-to-face appointment for a physical examination or an ECG.

You should also consult a GP if you are experiencing new palpitations, increased breathlessness, or if you are concerned about your stroke risk due to a family history of heart disease. Prompt consultation ensures that you receive the necessary screening and can begin preventative treatment as soon as possible.