at 22 hereinafter referred to as ventricular wenckebach during ventricular wenckebach like pacing behavior ventricular pacing occurs due to atrial tracking until a sensed atrial event falls within the preset pvarp allowing an intrinsically conducted r wave to occur which inhibits ventricular pacing for that sinus beat to restore ventricular pacing when the sensed atrial event falls within the preset pvarp the subsequent intrinsically conducted r wave is tracked and the ventricle is paced after a preset pacing delay subject to other variables discussed in further detail below as the sinus rate represented by dotted line 16 increases above the amtr as at 15 the average ventricular pacing rate slowly decreases due to wenckebach hike pacing at 22 until the sinus rate reaches a 2 1 ventricular tracking rate as at 24 once the sinus rate exceeds the preset ventricular maximum tracking rate or ventricular pacing is inhibited importantly unlike the resulting behavior of an atrial tracking pacemaker there is no significant hysteresis as the sinus rate falls below the vmtr or amtr of the ventricular tracking pacemaker fig6 22 are various plots illustrating the occurrence of a sensed p wave and the resulting tracked r wave plotted over time with respect to the ventricular tracking pacemaker 39 s preset timing intervals and varying sinus rates the time of occurrence of the ventricular pacing stimulation is indicated by labeled block u201c v u201d at 30 the time of occurrence of a sensed p wave is indicated by labeled block u201c p u201d at 32 a tracked p wave is indicated by.