I currently work on a telemetry floor and being a tele nurse means know how to interpret strips... Right? You'd be surprised by how many nurses I work with, where tele is their full time floor have no freakin' clue how I differentiate between SR with frequebt PAC's and Afib. P waves are not discernible in AFib. Think of it like the heart is trying to tell the atrias to contract but they're not too sure... Getting part of the way then pulling back. Thus the quivering " p waves". PAC's are simply another conductive spot in the atrias firing before the SA node. Review the actual conductive path of the heart along side the rhythms and it will clear a lot up!