Atrial Fibrillation, Explained in Less Than 2 Minutes

A heart with AFib marches to its own beat.

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That thump, thump, thump in your chest? Yea, that’s your heart beating. A normal heart has a steady beat that stays on pace like a metronome.

That beat stays regular thanks to cells in the heart that create electrical signals, which tell it to contract and pump blood. This pattern helps keep your blood flow consistent so your body can get the oxygen and nutrients it needs.

A heart with atrial fibrillation (AFib)? Now that’s a different story.

A heart with AFib marches to its own beat—literally. It happens when those electrical signals become faulty and random, and cause the heart’s two small upper chambers (atria) to beat irregularly and fast. This can make it quiver, kind of like gelatin.

This disruption can mess with blood flow, and your body needs a steady supply of blood to keep it working right. This can cause symptoms, such as:

  • Heart palpitations (feels like a fluttering in the heart)

  • Chest discomfort

  • Dizziness

  • Sweating

  • Fainting

  • Lightheadedness

  • Or shortness of breath

Because not all patients experience symptoms of AFib, many people do not even realize that they have it. That could be dangerous since AFib increases your risk of stroke by four to six times, according to the National Institute of Neurological Disorders and Stroke, as well as heart failure and other heart-related problems.

“If you have any symptoms that don’t feel right, you should always go and tell your doctor,” says Michelle Weisfelner Bloom, MD, a cardiologist at Stony Brook University Medical Center. “It’s very, very important for us to know if a patient is in atrial fibrillation, and you might not always know that yourself.”

Diagnosed with AFib? Learn more about how atrial fibrillation is treated.