I haven't experienced such PACs in recent months, but I have in the past (before I started magnesium supplementation). I think the effect of skipped beats (PACs) is that in the long interval between the full contractions of the ventricles, the heart fills more completely with blood than normally and so there is a larger volume of blood pumped, with more than usual force, through the system. This, potentially at least, creates a number of effects such as delivering an extra amount of oxygen to the brain, stimulating various baroreceptors and so forth, which produce a series of neurochemical responses in the body. Yes, such events can deliver quite a jolt. Nothing of any serious consequence ever happened to me as a result, however. Maybe if one happened when I was negotiating a steep turn at high speed on my motorcycle...