What is Atrial Fibrillation

Atrial fibrillation is an abnormal heart rhythm. The heart's electrical system normally sends regularly spaced, predictable signals, telling the heart muscle to contract. The heart has two upper chambers, called atria, and two lower chambers, called ventricles.

Each signal starts in the atria and travels to the rest of the heart. In atrial fibrillation, the electrical signals from the atria are fast and irregular.

In most cases, atrial fibrillation is due to an existing heart condition. But atrial fibrillation can occur in people with no structural heart problems. Treatment for atrial fibrillation include the use of drugs to regulate heart rate and prevent blood clots.