Atrial fibrillation

Atrial fibrillation is a heart rhythm disorder in which the atria do not contract in a coordinated way but quiver chaotically. The ventricles therefore respond irregularly, and the pulse becomes irregular and often fast. It is the most common persistent rhythm disorder in adults.

In itself it rarely poses a direct threat to life. Its seriousness lies elsewhere: blood pools in the quivering atrium, a clot can form there, and that clot can travel to a blood vessel in the brain and cause a stroke. It is because of this risk that atrial fibrillation is worth recognising even when it causes no symptoms.

How people notice it

The best-known description is a pounding or skipping heart, often with a feeling that the pulse has no rhythm. This may be joined by breathlessness during activities that used to be easy, unexplained tiredness, tightness in the chest, dizziness and reduced physical fitness.

In some people the disorder causes nothing at all. It is discovered by chance, when blood pressure is measured, on an ECG before a procedure, or through an alert from a smartwatch. Having no symptoms does not mean the risk of stroke is lower.

Episodes can be short and end on their own, or the rhythm can settle into a permanent form over time. It is therefore useful to note when the disorder appeared, how long it lasted and what you were doing at the time.

What makes it more likely and what triggers it

The most common companions are age, high blood pressure, heart failure, heart valve disease, diabetes, excess body weight and breathing disorders during sleep. An overactive thyroid is a cause that is always considered at the first assessment, as it can be cured.

An individual episode is often triggered by alcohol, even in an amount that seems harmless. Other triggers are a sleepless night, an acute infection, strenuous exertion, dehydration and the period after surgery.

For most people coffee is a weaker trigger than its reputation suggests. If your episodes reliably follow coffee, cut down on it; otherwise it is more important to limit alcohol and sort out your sleep.

When it is an emergency

Call 112 immediately if a pounding heart is accompanied by pain or strong tightness in the chest, severe shortness of breath, loss of consciousness or a feeling that you are about to collapse.

The same applies to signs of a stroke, which are particularly important with this rhythm disorder: sudden weakness or numbness on one side of the body, a drooping corner of the mouth, difficulty speaking or understanding, sudden disturbed vision and a sudden severe headache with confusion. In a stroke every minute counts, so do not wait for the signs to pass and do not drive yourself.

An episode of a fast irregular pulse without these signs is not a reason to call 112, but it is a reason to book an examination and not to put it off for months.

How it is confirmed

The diagnosis is made with an ECG that catches the disorder while it is happening. When episodes are short, a recording at the clinic often misses them, so a longer heart rhythm recording is made; how long is decided according to how often the symptoms occur.

This is followed by an ultrasound of the heart, which assesses the size of the atria, the function of the heart muscle and the valves. Important laboratory tests include thyroid hormones, a blood count, electrolytes and kidney function, as they also affect the choice of medicines.

A reading from a smartwatch or phone is a useful hint, but it is not a diagnosis. Show the recording to the doctor; confirmation must come from an ECG.

How it is treated

Treatment has two separate parts that are often confused. The first is preventing stroke with blood-thinning medicines. Whether you need them is not decided by how often you feel the disorder, but by a risk assessment that takes into account age, blood pressure, diabetes, heart failure and previous vascular events. Aspirin is not a suitable substitute for this purpose.

The second part is controlling the rhythm or the rate. For some people the goal is a return to normal rhythm, for others slowing the pulse while the fibrillation continues. The decision depends on age, symptoms, how long the disorder has lasted and the condition of the heart.

When medicines are not enough, the conversation turns to electrophysiological procedures, including catheter ablation. These are carried out at institutions equipped for them, and the cardiologist will explain what the procedure involves and where to refer you.