Electrocardiogram strips showing an atrial premature beat, followed by a noncompensatory pause

Simultaneous electrocardiographic recording from surface leads V1, II, and V5 shows an atrial premature beat (P'), which is conducted with aberration. The P wave is different from that of the sinus beat and the PR interval is longer,due to delayed conduction in the atrioventricular node. A noncompensatory pause is present (ie, the interval measured from the sinus beat before and after the atrial premature beat is less than 2 sinus RR intervals).