Mondo Description 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)

Disease Ontology Description A heart conduction disease that is characterized by uncoordinated electrical activity in the heart's upper chambers (the atria), which causes the heartbeat to become fast and irregular and has symptoms palpitations, weakness, fatigue, lightheadedness, dizziness, confusion, shortness of breath and chest pain.