What is atrial fibrillation?
Atrial fibrillation is an alteration of the normal heart rate, an arrhythmia. There are many types of arrhythmic alterations, from mild unimportant alterations to more severe alterations that require immediate intervention.
In the case of atrial fibrillation, the heart contracts and relaxes in an irregular rhythm. This means that the upper chambers of the heart (the atrium) beat in an irregular manner instead of beating efficiently to move the blood towards the ventricles. People who experience atrial fibrillation may feel their pulse becomes more irregular (not rhythmic), and in the majority of cases, quicker, but it can also become slower or stay the same.
If you would like to find more detailed information you can consult: Atrial Fibrillation: a guide for patients. The information contained in the guide is extensive. Some sections try to explain what atrial fibrillation is, others deal with practical matters as to how to live with it.