NCIt definition : A disorder characterized by an electrocardiographic finding of a supraventricular
arrhythmia characterized by the replacement of consistent P waves by rapid oscillations
or fibrillatory waves that vary in size, shape and timing and are accompanied by an
irregular ventricular response. (CDISC);
Alternative definition : FDA: Irregular heart rhythm, usually associated with a rapid rate, that is caused
by abnormal electrical activity within the atrial.; CTCAE: A disorder characterized by a dysrhythmia without discernible P waves and an
irregular ventricular response due to multiple reentry circuits. The rhythm disturbance
originates above the ventricles.; NICHD: An irregular heart rhythm, usually associated with a rapid rate, that is caused
by abnormal electrical activity within the atria.;