What's the difference between vfib and afib?

Top vs Bottom : Ventricular fibrillation is from the bottom chamber; vf is worse; it usually causes cardiac arrest which is often fatal. Atrial fibrillation - from the top chamber- while not as severe, also has significant health risks. It increases the risk of stroke, which can be disabling or fatal.

Rhythm : Atrial fib is a rhythm that comes from the upper right chamber. It is a common abnormal rhythm. It has multiple foci, and doesn't follow a synchronized path. Ventricular fib, come from the lower left chamber and is a rhythm that is not sustainable for life. The heart is unable to adequately pump blood and perfuse the heart.

Location, prognosis: Fibrillation is disorganized electrical activity in cardiac cells due to numerous reasons. When it happens in the upper chambers of the heart, it's called atrial fibrillation and when it happens in the lower chambers of the heart, it's called ventricular fibrillation. Ventricular fibrillation leads to death unless the heart is defibrillated. Atrial fibrillation does not, but it can lead to stroke