Atrial fibrillation is a common type of arrhythmia (abnormal heart rhythm). It's a fast and chaotic beating of the atrial chambers (the upper 2 chambers of the heart), the electrical signal that causes the heart to beat becomes uncoordinated. The atria beat so rapidly as fast as 350 to 600 beats a minute instead of a single, forceful contraction. It mainly affects older people mostly due to wear and tear on the heart, those who had high blood pressure or other heart problems. Atrial fibrillation can over time cause a stroke or death.
Attribution: Straight Talk Foundation