1 in 7
strokes is caused by atrial fibrillation
5×
higher risk of ischaemic stroke with AFib
12.1m
people in the US projected to have AFib by 2050
Often 0
symptoms — AFib can be completely silent
1Why AFib matters more than it sounds
Atrial fibrillation is an irregular, often rapid heart rhythm. On its own it may feel like nothing. Its danger is what it does to blood flow.1
When the upper chambers of the heart quiver instead of beating cleanly, blood can pool and form clots. If a clot travels to the brain, it causes a stroke. That is why a rhythm problem many people never feel is behind roughly one in seven of all strokes — and why AFib carries about a fivefold increase in ischaemic stroke risk even after accounting for other risk factors.1
In the US, AFib appeared on 232,030 death certificates in 2021 and was the underlying cause in 28,037 of them. It drives over 454,000 hospitalisations a year.1
2What it feels like — and why that's the problem
AFib is episodic in many people. It can come and go, which is exactly why a single check in a clinic can miss it.
⚑ Symptoms to know
- Irregular heartbeat or fluttering
- Heart palpitations
- Lightheadedness
- Extreme fatigue
- Shortness of breath
- Chest pain
⚠ The catch
- Many people have no symptoms at all. The CDC lists asymptomatic AFib alongside the symptom list1
- Episodes may last minutes and stop before you reach a doctor
- A normal reading today does not rule it out tomorrow
3Who is most at risk
The CDC lists these risk factors. High blood pressure alone accounts for roughly one in five AFib cases.1
| Risk factor | Risk factor |
|---|
| Advancing age | Heart failure |
| High blood pressure | Ischaemic heart disease |
| Obesity | Hyperthyroidism |
| Diabetes | Chronic kidney disease |
| Moderate-to-heavy alcohol use | Smoking |
4What a wearable ECG actually does
Worth being precise here, because the gap between "detects an irregular rhythm" and "diagnoses AFib" is where most confusion lives.
✓ What it can do
- Record a single-lead ECG trace, which can flag an irregular rhythm
- Catch episodic AFib that happens outside clinic hours — its real advantage
- Produce a timestamped trace you can show a clinician
- Prompt you to seek a proper assessment you might otherwise skip
✗ What it cannot do
- Diagnose. Clinical diagnosis uses a 12-lead ECG read by a clinician — a watch records one lead
- Detect heart attack. A wearable ECG is not designed for this
- Rule AFib out. A normal trace means normal at that moment, nothing more
- Replace a Holter monitor or longer-term clinical rhythm monitoring
If you get an irregular-rhythm alert
Don't panic and don't ignore it. Save the trace, note the time and what you were doing, and take it to a doctor. False positives happen — so do true positives in people who had no idea.
Seek emergency care immediately for chest pain, severe shortness of breath, fainting, or sudden weakness or numbness on one side, or difficulty speaking — these are stroke and cardiac emergency signs, not something to check on a watch.