A PAC is not a rhythm, it is an ectopic beat that originates from the Atria. The underlying rhythm is Sinus Rhythm at 69bpm with PAC. Correct the causes to avoid usurpation (taking over) of Atrial rhythms. It can occur every other normal beat (Bigeminal), every other third normal beat (Trigeminal), or every other fourth normal beat (Quadrigeminal). It can also occur in pairs (coupled) or three or more in a row (Run, Burst, PAT). Follow AHA ACLS 2005 Guidelines narrow complex tachycardia algorithm.