https://www.sciencedaily.com/releases/2020/03/200331093248.htm

Atrial fibrillation (AF) is a heart rhythm condition that causes an irregular and sometimes, abnormally fast heart rate. In AF, the heart's upper chambers (atria) contract randomly and sometimes so fast that the heart muscle cannot relax properly between contractions. This reduces the heart's efficiency and performance -- but also leads to a higher risk of blood clots.

AF is the most common heart rhythm disturbance, affecting around one million people in the UK. People with AF are at increased risk of having a stroke and dying, as well as heart failure and dementia. Currently, low detection due to lack of visible symptoms and non-adherence are major problems in current management approaches for patients with suspected AF.