Atrial Fibrillation Video
Atrial fibrillation or AF, is a common arrhythmia. An arrhythmia is a problem with the speed or rhythm of the heartbeat. A disorder in the heart’s electrical system causes atrial fibrillation and other types of arrhythmias.
Atrial Fibrillation occurs when rapid, disorganized electrical signals in the heart’s two upper chambers, called the atria, cause them to contract very fast and irregularly. As a result, blood pools in the atria and isn’t pumped completely into the heart’s two lower chambers, called the ventricles. When this happens, the heart’s upper and lower chambers don’t work together as they should.
Often, people who have Atrial Fibrillation may not even feel symptoms. However, even when not noticed, atrial fibrillation can lead to an increased risk of stroke. In many patients, particularly when the rhythm is extremely rapid, atrial fibrillation can cause chest pain, heart attack, or heart failure. Atrial Fibrillation may occur rarely or every now and then, or it may become a persistent or permanent heart rhythm lasting for years.
Understanding the Electrical Problem in Atrial Fibrillation
In atrial fibrillation, the heart’s electrical signal begins in a different part of the atria or the nearby pulmonary veins and is conducted abnormally. The signal doesn’t travel through normal pathways, but may spread throughout the atria in a rapid, disorganized way. This can cause the atria to beat more than 300 times a minute in a chaotic fashion. The atria’s rapid, irregular, and uncoordinated beating is called fibrillation.
The abnormal signal from the SA node floods the AV node with electrical impulses. As a result, the ventricles also begin to beat very fast. However, the AV node can’t conduct the signals to the ventricles as fast as they arrive, so even though the ventricles may be beating faster than normal, they aren’t beating as fast as the atria. The atria and ventricles no longer beat in a coordinated fashion, creating a fast and irregular heart rhythm. In atrial fibrillation, the ventricles may beat up to 100–175 times a minute, in contrast to the normal rate of 60–100 beats a minute.
When this happens, blood isn’t pumped into the ventricles as well as it should be, and the amount of blood pumped out of the ventricles is based on the randomness of the atrial beats. In atrial fibrillation, instead of the body receiving a constant, regular amount of blood from the ventricles, it receives rapid, small amounts and occasional random, larger amounts, depending on how much blood has flowed from the atria to the ventricles with each beat.
Most of the symptoms of atrial fibrillation are related to how fast the heart is beating. If medicines or age slow the heart rate, the effect of the irregular beats is minimized.
Atrial fibrillation may be brief, with symptoms that come and go (also called paroxysmal) and end on their own, or it may be persistent and require treatment. Or, atrial fibrillaton can be permanent, in which case medicines or other interventions can’t restore a normal rhythm.