Medically reviewed by Dr Nabila Laskar, Consultant Cardiologist (GMC 7040901). Atrial fibrillation (AFib) is the most common heart rhythm disorder, causing the heart's upper chambers to beat irregularly and often rapidly. It affects an estimated 1.4 million people in the UK and significantly increases stroke risk if untreated.
Symptoms include palpitations, fatigue, breathlessness, dizziness, and reduced exercise tolerance. Some people with AFib experience no symptoms at all, which is why it is often detected incidentally during routine ECG screening.
In AFib, blood can pool and clot in the heart's upper chambers due to irregular contraction. If a clot travels to the brain, it can cause a stroke. This is why AFib diagnosis typically includes stroke risk assessment and, where appropriate, blood-thinning medication.
AFib is diagnosed via ECG, which captures the heart's electrical rhythm. Because AFib can be intermittent, a Holter monitor worn over 24 hours to 7 days is often used to catch episodes that a single ECG might miss.
Treatment depends on the individual and may include rate-control medication, rhythm-control medication, blood thinners to reduce stroke risk, or in some cases a procedure such as cardioversion or ablation.
AFib itself is not usually immediately life-threatening, but it significantly increases stroke risk if left untreated, which makes diagnosis and management important.
Some people achieve long-term rhythm control through medication, lifestyle changes, or procedures such as ablation, though AFib can be a recurring condition requiring ongoing management.
Common triggers include alcohol, caffeine, stress, illness, dehydration, and lack of sleep, though AFib can also occur without an identifiable trigger.
AFib is a specific, diagnosable rhythm abnormality confirmed by ECG, whereas palpitations are a symptom that can have many causes, including AFib.