When something goes wrong with this system, it's usually because of other health problems that are causing wear and tear on the heart or making it hard for the heart to do its job. Sometimes it's because of lifestyle habits-such as smoking or heavy drinking-that are hard on the heart.
Problems that affect the heart's structure
Atrial fibrillation is often caused by a health problem that directly affects the heart, including:
Other health problems
Atrial fibrillation can also be caused by other health problems, including:
In some cases, doctors cannot find the cause of atrial fibrillation.