The QRS duration on the left  is 0.06 seconds, a normal value.   This duration indicates that all the elements of the specialized conduction system are functioning normally in this beat.  In the center, the QRS duration is 0.12 seconds.  This prolonged duration, , but not so long as that of a ventricular beat, indicates that some but not all elements of the specialized conduction system are functioning normally.  This intraventricular conduction delay, a bundle branch block, gives rise to the "rabbit ears", the jagged peaks in the QRS.  On the right, the QRS duration is about 0.16 seconds.   This duration, together with the slurred shape, tells us that the pacemaker is a focus within the ventricular myocardium and that the specialized conduction system is not organizing these depolarizations at all.