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:
- high blood pressure (hypertension)
- disease of your blood vessels (atherosclerosis)
- heart valve disease
- congenital (from birth) heart disease
- cardiomyopathy
- pericarditis
It's also associated with other medical conditions, including:
- an overactive thyroid gland
- pneumonia
- asthma
- chronic obstructive pulmonary disease (COPD)
- lung cancer
- type 2 diabetes
- pulmonary embolism
- carbon monoxide poisoning
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'.
Triggers
Certain situations can trigger an episode of atrial fibrillation, such as:
- drinking too much alcohol, particularly binge drinking
- living with obesity
- drinking lots of caffeine, such as tea, coffee or energy drinks
- taking illegal drugs, particularly amphetamines or cocaine
- smoking