PVC's are not uncommon among the general population and some folks don't even know they have them. HOWEVER, if you feel faint or short of breath when you are having them, get to a doctor of hospital asap because then it is very possibly AFIB
It's when they become couplets, bijeminy, or trijeminy that it becomes an issue. Most of the times PVC'S occur due to stress or excessive caffeine or nicotine intake.