About atrial fibrillation

Learn about atrial fibrillation and its causes. 

What is atrial fibrillation?

During a regular heartbeat, the heart’s top 2 chambers send an electrical signal that triggers the heart to pump blood.

Atrial fibrillation happens when the signal that guides the heart becomes irregular. This causes fast, uneven contractions of the chambers. As a result, blood does not pump completely through the heart. Sometimes blood is also pumped poorly through the body.

Atrial fibrillation is usually a congenital heart disease. This means that you were born with this problem in your heart’s structure.

Causes of atrial fibrillation

Some people have atrial fibrillation for no reason. Other people have it because of substance use, such as:

• alcohol
• stimulant medications like antihistamines

Still others have atrial fibrillation due to physical conditions, such as:

• physical or emotional stress
• heart surgery or a heart attack
• swelling of the sac around the heart
• a blood clot (thickened blood) in the lung
• overactive thyroid gland, which makes and releases more thyroid hormone than the body needs, leading to:
  • anxiety
  • weight loss
  • nervousness
  • hand tremors
  • sleep problems
  • rapid heartbeat
  • excessive sweating

Atrial fibrillation can also be a problem that keeps coming back. It may be caused by:

• high blood pressure (hypertension)
• coronary artery (artery of the heart) disease
• diseases of the heart valves or heart muscle

Atrial fibrillation is not usually serious in otherwise healthy people. However, it can lead to complications if it is not treated and monitored by your health care provider, such as:

• stroke
• heart failure