Ventricular Fibrillation | Reference Guide.

EKG Features

Rate: Unmeasurable
Rhythm: Highly irregular
P Wave: Absent
PR Interval: Not measurable
QRS: None

Ventricular fibrillation is an abnormal, irregular heart rhythm with uncoordinated electrical activity and contractions. Because the ventricles are not contracting, blood is not circulating. Ventricular fibrillation is a medical emergency requiring immediate treatment.
External Source: http://www.nlm.nih.gov/medlineplus/ency/article/007200.htm
MedlinePlus