Atrial fibrillation, often called AF, is a common heart rhythm in which the upper chambers of the heart beat irregularly. It is usually manageable; the two things that matter most are stroke risk and symptom control, and both are treatable.
What AF actually is
Normally, each heartbeat starts from an organised electrical signal. In AF, electrical activity in the atria becomes irregular and disorganised, so the pulse often feels irregular rather than steady.
That irregularity can feel like fluttering, racing, breathlessness, reduced exercise tolerance or fatigue. Some people feel nothing at all, and AF is only found on an ECG, watch recording or heart monitor.
Why AF matters
AF matters because blood may move less smoothly through the atria, which can allow clots to form. If a clot travels to the brain, it can cause a stroke.
Your personal stroke risk cannot be judged from symptoms alone. A doctor assesses it formally using your age, medical history and other risk factors, and that risk can often be reduced with treatment.
What can change it
Real data
In REVERSE-AF (Middeldorp et al., Europace 2018, doi:10.1093/europace/euy117), greater weight loss was associated with greater improvement in the pattern of atrial fibrillation. Among 355 people with AF and a BMI of 27 or above:
- Losing less than 3% of body weight: 26% went from persistent AF back to occasional or no AF — and 41% got worse.
- Losing 3–9%: 49% improved.
- Losing 10% or more: 88% improved, and only 3% got worse.
Two honest limits. This followed people offered a weight-management programme rather than randomising them, so it shows a strong association rather than proof of cause. And everyone in it had a BMI of 27 or above, so it does not tell you what happens if your weight is already in the healthy range.
Source: Middeldorp ME, Pathak RK, Meredith M, et al. PREVEntion and regReSsive Effect of weight-loss and risk factor modification on Atrial Fibrillation: the REVERSE-AF study. Europace 2018;20(12):1929-1935. doi:10.1093/europace/euy117
AF can be influenced by alcohol, poor sleep, stress, excess weight, high blood pressure, sleep apnoea, thyroid disease, infection, dehydration and some stimulants or medicines. The relevant factors differ from person to person.
Lifestyle changes can help some people reduce AF burden or improve symptoms, but the size of the effect depends on the person and the evidence source. It is better to discuss realistic, safe changes with your GP or cardiologist than to chase a single online rule.
What treatment usually involves
Treatment is usually discussed in categories. Rate control slows how fast the lower chambers respond. Rhythm control tries to restore or maintain a more regular rhythm. Ablation treats small areas of heart tissue that help sustain the rhythm problem. Anticoagulation reduces clot and stroke risk in people whose formal risk assessment supports it.
A doctor chooses between these options using the type of AF, symptoms, heart structure, other conditions, medicine risks and your preferences. This page is not a treatment recommendation.
When AF needs urgent help
Fast AF with chest pain, breathlessness at rest or too breathless to speak normally, fainting or feeling so unwell that you cannot stand or function normally needs urgent assessment. Call 999 for those symptoms.
Would you like specialist advice?
I offer face-to-face appointments, normally 30 minutes, at the Finchley Road clinic.