Glossary

atrial fibrillation

Atrial fibrillation is a type of arrhythmia where the heart’s atria (the chambers where blood enters the heart) beat very rapidly and irregularly. This is not usually acutely life-threatening, but with time it can increase the risk of having a stroke. This is due to small blood clots that are then more likely to occur in the atria because the normal flow of blood is affected.