Atrial fibrillation (AFib) is a type of heart arrhythmia that causes the top chambers of your heart, the atria, to quiver and beat irregularly. AFib used to be described as chronic or acute, with ...

Atrial fibrillation (AFib) is a condition that causes your heart to beat in an irregular rhythm. One way to classify AFib is by what’s causing it. Valvular AFib and nonvalvular AFib are terms used to ...

Atrial fibrillation, or AFib, is the most common type of irregular heartbeat. About 2.7 million Americans have it. AFib happens when the electrical activity of the heart isn’t working the way it’s ...