Other sites in our network: What's on TV | Now | Pick Me Up | Puzzles and Prizes

What is atrial fibrillation?

Average rating:

If you have atrial fibrillation (AF) then:

Your heart rate is usually a lot faster than normal.
Your heart beat is irregular. This is called an abnormal heart rhythm or an 'arrhythmia'.
The force of each heart beat can vary in intensity.

What happens is that the normal controlling 'timer' in the heart is over-ridden by many random electrical impulses that 'fire off' from the heart muscle in the atria. The atria then 'fibrillate'. This means that the atria only partially contract - but very rapidly (up to 400 times per minute). Only some of these impulses pass through to the ventricles in a haphazard way. Therefore, the ventricles contract anywhere between 50 and 180 times a minute, but usually between 140 and 180 times a minute. However, the ventricles contract in an irregular way and with varying force.

Therefore, if you have AF and feel your pulse, you may count up to 180 beats per minute. Also, the force of each beat can vary, and the pulse feels erratic.

Classification of AF

AF is commonly classified in the following way:

Paroxysmal AF. The word paroxysmal means 'recurring sudden episodes of symptoms'. If you have paroxysmal AF it means that you have episodes of AF that come and go. Each episode comes on suddenly, but will stop without any treatment within seven days (usually within two days). Each episode stops just as suddenly as it starts and the heart beat goes back to a normal rate and rhythm. The period of time between each episode (each paroxysm) can vary greatly from case to case. Although paroxysmal AF means that it will stop on its own, some people with paroxysmal AF take treatment as soon as the AF develops to stop it as quickly as possible after it starts.
Persistent AF. This means AF that lasts longer than seven days and is unlikely to revert back to normal without treatment. However, the heart beat can be reverted back to a normal rhythm with 'cardioversion' treatment (see later). Persistent AF tends to be recurrent so it may come back again at some point after successful cardioversion treatment.
Permanent AF. This means that the AF is present long-term and the heart beat has not been reverted back to a normal rhythm. This may be because cardioversion treatment was tried and was not successful, or because cardioversion has not been tried. People with permanent AF are treated to bring their heart rate back down to normal, but the rhythm remains irregular (see below). Permanent AF is sometimes called 'established AF'. Most people with AF have permanent AF.