Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.

Synonyms: Fibrillation, Familial Atrial, Fibrillations, Persistent Atrial, Auricular Fibrillation, Atrial Fibrillations, Paroxysmal, Auricular Fibrillations, Fibrillation, Atrial, Fibrillations, Paroxysmal Atrial, Persistent Atrial Fibrillation, Atrial Fibrillation, Familial, Paroxysmal Atrial Fibrillations, Atrial Fibrillation, Paroxysmal, Fibrillations, Familial Atrial, Fibrillation, Paroxysmal Atrial, Fibrillation, Auricular, Fibrillation, Persistent Atrial, Atrial Fibrillation, Atrial Fibrillations, Persistent, Fibrillations, Auricular, Persistent Atrial Fibrillations, Familial Atrial Fibrillations, Atrial Fibrillations, Atrial Fibrillation, Persistent, Familial Atrial Fibrillation, Atrial Fibrillations, Familial, Fibrillations, Atrial, Paroxysmal Atrial Fibrillation