Now study the interval, or pause, between the premature wide QRS complex labeled #1 and the following sinus beat. As shown in the ladder diagram below the ECG strip, this post extrasystolic pause measures 1.00 seconds and is greater than both the normal RR interval of 0.72 seconds and the 0.80 second pause that follows the aberrantly conducted beat (#2). The reason for this difference is that the ventricular premature beat (#1) is followed first by a non-conducted sinus P wave (arrow) with a PP interval of 0.72 seconds and then by normally conducted P wave with the same PP interval. Note that the interval between the normally conducted QRS complexes that precede and follow the ventricular premature beat (1.44 seconds) is equal to two normal RR intervals. This indicates that the post extrasystolic pause is fully compensatory, i.e. is a compensatory pause.