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Causes - Atrial fibrillation

The exact cause of atrial fibrillation is often unknown. It's more common with age.

Atrial fibrillation is common in people with other heart conditions, such as:

It's also associated with other medical conditions, including:

Not everyone with atrial fibrillation has one of these conditions. It can sometimes affect people who are physically very fit and do regular endurance exercise, such as long-distance athletes.

When no other conditions are associated with atrial fibrillation, it's known as 'lone atrial fibrillation'.


Certain situations can trigger an episode of atrial fibrillation, such as:

Page last reviewed: 26 July 2023
Next review due: 26 July 2026