Answer 12

12.  Choice C is the correct answer.  A premature atrial contraction originates from an ectopic focus in the atrium that appears much earlier than normal P wave in the EKG.  With a wandering atrial pacemaker, the pacer maker wanders from focus to focus.  The P waves are various shapes since the origin of the pacemaker comes from different areas in the atria.  With a premature junctional contraction the contraction occurs from an ectopic focus in the AV junction and fires before the normal cycle.  Usually inverted P waves occur before, during, or immediately after the QRS complex.  With premature ventricular contractions, there is a widened QRS complex occurring early then expected with a compensatory pause.