What Is Atrial Fibrillation?

Atrial fibrillation is an electrical disorder affecting the upper chambers of the heart, called the atria.  In this condition, electrical signals in the upper chambers circulate rapidly.  Rather than taking a specific path within these chambers, the electrical signal swirls around at a rate of many hundreds of beats per minute.  An analogy of a sandstorm or a windstorm may be used.  The impulse in the upper chamber can travel from the upper chamber to the lower chamber by a connector called the AV node, like a staircase connecting the top to the bottom floors of the building.

A consequence of these rapid electrical signals is that the upper chambers do not contract in an organized fashion. Therefore, rather than pumping out blood with considerable force, as during normal rhythm, the blood empties from the atria to the ventricles passively on its own.

This decreased pumping function may result in the patient having less energy or cause a limitation of exertion. In addition, the lack of coordinated contraction of the upper chambers can lead to less forceful blood flow and therefore some stagnation or pooling of blood within the heart, within the upper chambers.  This may lead to an increased risk of blood clots or stroke.

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