Atrial Fibrillation

The term Atrial Fibrillation (AF) describes one of a number of common types of irregular heart rhythms. It is used to describe a very fast, uncontrolled and irregular heartbeat which occurs when the electrical impulses in the upper chambers of the heart (the Atria) have become disorganised.

Normally the resting heart beats at about 70-100 beats per minute, but when Atrial Fibrillation occurs, this rate sometimes reaches 300-500 beats per minute.

The electrical impulses which control the heart's beating originate in the body's natural pacemaker inside the right atrium - the sino atrial node. This causes the atria to contract. Every contraction of the atrium in the normal heart leads to a contraction of the ventricle (the lower chamber of the heart) as the electrical impulse moves through the heart.

Atrial fibrillation is caused by electrical problems in the atria

In Atrial Fibrillation this system becomes disorganised. The atria no longer contract in a regular manner but twitch and quiver very rapidly and at random. This, in turn means that the ventricles no longer respond efficiently. They, too, become disorganised because of the lack of systematic electrical impulses.

The ventricles beat irregularly and therefore no longer pump the blood around the body efficiently. Thus, in Atrial Fibrillation, the heart is pumping the blood around the body in a weak and ineffective manner.

Forms of atrial fibrillation

There are three forms of Atrial Fibrillation:-

1. Short periods where the heart beats erratically and quickly but soon settles down again.
2. Periods where the heartbeat is so rapid, erratic and persistent that some form of medical help is required to restore it to normality. This is usually attained by taking prescribed drugs.
3. Permanent fibrillation where patients need to take medication for the rest of their life.

Atrial Fibrillation Cause >>