Definition for atrial fibrillation

Atrial fibrillation (AF or afib) is a cardiac arrhythmia (abnormal heart rhythm) that involves the two upper chambers (atria) of the heart. more

Atrial fibrillation (AF or afib) is a cardiac arrhythmia (abnormal heart rhythm) that involves the two upper chambers (atria) of the heart. It is defined as being irregularly irregular, and can often be identified as such when taking a pulse. Atrial fibrillation is the most common arrhythmia; risk increases with age, with 8% of people over 80 having AF. In atrial fibrillation, the electrical impulses that are normally generated by the sinoatrial node are replaced by disorganized activity in the atria, leading to irregular conduction of impulses to the ventricles that generate the heartbeat. The result is an irregular heartbeat. This may be continuous (persistent or permanent AF) or alternating between periods of a normal heart rhythm (paroxysmal AF). The natural tendency of atrial fibrillation is to become a chronic condition. Chronic AF leads to an increased risk of death. less