Assertion: atrial fibrillation | /r/HasProperty | complex condition
Facets:
Source sentences:
text: Caused by abnormal, irregular electrical signals from the conduction system, atrial fibrillation is a complex condition affecting close to five million people in the United States.
text: Atrial fibrillation is a complex arrhythmia (abnormal heart rhythm) affecting the upper chambers of the heart (the atria) primarily.