Ventricular fibrillation is technically not a rapid heart rhythm because the heart ceases to beat. In ventricular fibrillation, the ventricles do not have a coordinated electrical pattern and the ventricles, instead of beating, just jiggle, or fibrillate. Since the heart doesn’t beat, blood is not circulated to the body or brain and all bodily …
https://www.medicinenet.com/heart_rhythm_disorders/article.htm

