Just wondered if anyone could "shed any light" into this question please. I have many episodes of AF and now and then Atrial Fluttering - today I read in the Heart Magazine that:- Ventricular fibrillation (VF) - A life-threatening heart rhythm that starts in the ventricles. This causes the heart to quiver or "fibrillate" in a disordered way and the heart stoops pumping blood around the body. Just concerned when my heart acts this way when in AF or A Flutterings.