Atrial fibrillation is a heart rhythm disorder. It is caused by irregularities in the electrical signals from part of the heart.
The heart is a muscle that continuously contracts and relaxes rhythmically throughout our lives. Each heartbeat is stimulated by an electrical signal generated in the conduction system of the heart.
A normal heartbeat repeats 60 to 100 times per minute. Sometimes, due to a malfunction of the conduction system, the heart beats too fast, too slow, or irregularly. The electrical activity of the heart can be measured with an electrocardiogram study.
In a normal heartbeat, the heart signal travels through the heart along a certain route. The signal begins in the sinoatrial node, abbreviated SA node, which is located in the right atrium. The SA node stimulates the atria to contract, pushing blood into the ventricles. The electrical signal then goes through the atrioventricular node, abbreviated AV node, enters the ventricles of the heart. The signal causes the ventricles to contract, pumping blood to the lungs and the rest of the body.
Atrial fibrillation is one of the types cardiac arrhythmias. The phenomenon is caused by irregularities in the electrical signals from the atria. During such an arrhythmia, the normal, coordinated contractions of the atria and ventricles are disrupted, and the heart can no longer pump blood efficiently to the body.
In people who suffer from atrial fibrillation, a large number of rapid electrical impulses are sent from different parts of the heart to the atria. These impulses cause a very fast and chaotic heart rhythm. This rhythm causes the atria contractions to become irregular. These irregular contractions do not fill the ventricles properly with blood, and therefore the contractions of the ventricles also become irregular. The heart rate can reach 100 to 175 beats per minute, or even more.
Atrial fibrillation can be the cause of fainting, weakness, blood clot formation, and other complications. Atrial fibrillation can be treated with medications or surgery. In some patients, a pacemaker may be placed to regulate the heart rhythm.