Atrial fibrillation (also called AFib or AF) is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications. At least 2.7 million Americans are living with AFib.

Normally, your heart contracts and relaxes to a regular beat. In atrial fibrillation, the upper chambers of the heart (the atria) beat irregularly (quiver) instead of beating effectively to move blood into the ventricles.

If a clot breaks off, enters the bloodstream and lodges in an artery leading to the brain, a stroke results. About 15–20 percent of people who have strokes have this heart arrhythmia. This clot risk is why patients with this condition are put on blood thinners.

Although atrial fibrillation can feel weird and frightening, an “attack of AFib” usually doesn’t have harmful consequences by itself. The real danger is the increased risk for stroke. Even when symptoms are not noticeable, AFib can increase a person’s risks for stroke and related heart problems. Watch this video to show how a clot can cause a stroke as Robin Stoloff talks with Dr. William Hirsch, Chair of Cardiology at Deborah Heart and Lung Center.

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