next cycle to the following the atrial maximum tracking rate interval is set to equal the preset rv interval the sav interval is set to equal the preset rav interval and the pvarp interval set to be less than the time of the rv interval minus the pr interval with these reset timing intervals a conventional atrial tracking algorithm is used to control ventricular pacing for the cycle a conventional atrial tracking algorithm may include the following when a p wave is sensed outside of pvarp the sav interval is initiated and when it expires the ventricle is paced unless the maximum tracking rate interval has not expired in which case the ventricular pace is delayed until the end of the maximum tracking rate interval after the cycle the rv interval sav interval and pvarp intervals return to their preset intervals those skilled in the art will appreciate that this algorithm will produce the same pacing behavior as that described above in conjunction with fig2 it is recognized that the length of the rv delay and rav intervals may be varied relative to other timing intervals of the pacemaker to control the ventricular tracking behavior of the ventricular tracking pacemaker further the varied length of the rv delay and rav intervals may also depend on features of a conventional atrial tracking pacemaker this invention has.