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What Causes Atrial Fibrillation?

Atrial fibrillation (AF) occurs if the heart's electrical signals don't travel through the heart in a normal way. Instead, they become very rapid and disorganized.

Damage to the heart's electrical system causes AF. The damage most often is the result of other conditions that affect the health of the heart, such as high blood pressure and coronary heart disease.

The risk of AF increases as you age. Inflammation also is thought to play a role in causing AF. 

Sometimes, the cause of AF is unknown.

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September 18, 2014 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.