Skip to content

Press your hand against your chest. Those little thumps you feel are your heart pumping, moving blood into and out of its chambers and through the rest of your body.

Normally, the top part of your heart (the atria) squeezes first, then the bottom part (the ventricles). The timing of these contractions is what moves the blood. But for more than 2 million Americans, the electrical signals that control this system are off-kilter. Instead of working together, the atria do their own thing. This fast, fluttering heartbeat, what doctors call arrhythmia, is atrial fibrillation, or AFib.

More than annoying, it can be serious. Because your blood isn't moving well, you're at greater risk for heart failure. That's when your heart can't keep up with the needs of your body. Blood can also pool inside your heart and form clots. If one gets stuck in your brain, you can have a stroke.

Who Gets It?

Anyone can have AFib, but it's more common in people who are 60 or older.

Other heart problems can make it more likely:

People with certain medical conditions have a greater chance, too:

Certain medicines (including adenosine, digitalis, and theophylline) can raise the risk of AFib.

Sometimes, it's linked to:

  • Heavy alcohol, caffeine, or drug use
  • Infections
  • The genes you got from your parents


When your heart is in AFib, you might feel:

  • Like your heart is racing or fluttering in your chest (palpitations)
  • Fatigued or weak
  • Dizzy or lightheaded
  • Chest pain or pressure
  • Short of breath

If you have these symptoms, call your doctor and make an appointment as soon as possible. If they last more than 24 hours, go to the hospital.

Sometimes it doesn't cause any symptoms, though. If you're at risk, talk to your doctor about your chances for having AFib, and get regular checkups.

Life With Atrial Fibrillation

Tips and facts to help you
live your best with atrial
View slideshow

Atrial Fibrillation Poll

Which atrial fibrillation symptom bothers you the most?

View Results

WebMD Video Series

Click here to wach video: Atrial Fibrillation

Discover what happens during atrial fibrillation and what your doctor can do to manage it.

Click here to watch video: Atrial Fibrillation