Specifications

Automatic PVARP Extension After a PVC
The programmed PVARP duration may be overridden when a pacemaker-
defined premature ventricular contraction (PVC) occurs. A pacemaker-
defined PVC starts an extended PVARP to 400 ms if the programmed
PVARP is less than 400 ms. This extended PVARP causes retrograde P-
waves within 400 ms to be identified as refractory sensed events.
■
In dual chamber modes, except VDD, a pacemaker-defined PVC is any
ventricular sensed event (refractory or nonrefractory) that follows a
ventricular event (pace, refractory or nonrefractory sense) without an
intervening atrial event (pace, refractory or nonrefractory sense).
■
In the VDD mode, a ventricular paced event delivered at the Lower
Rate and not preceded by an atrial sensed event is also considered a
PVC.
In the DDDR mode, a pacemaker-defined PVC always enables Non-
Competitive Atrial Pacing (NCAP) for one cycle when NCAP is
programmed OFF. This occurs when the PVARP extension occurs. If Mode
Switch is programmed ON, pacemaker-defined PVCs are not detected
when the pacemaker switches to a non-atrial tracking mode. Detection
resumes upon return to an atrial tracking mode.
NOTE: The pacemaker automatically counts PVCs and runs of two or
more consecutive PVCs. Both counts are included in the Event Summary
report described in Chapter 17.
Automatic PVARP Extension After a PMT
The programmed PVARP duration may be overridden by the PMT
Intervention feature. When PMT Intervention is programmed ON and a
pacemaker-defined PMT is detected, the PVARP is forced to 400 ms after
the ninth paced ventricular event of the PMT.
Refer to Chapter 14 for further details on PMT Intervention and its
interactions with PVARP.
12-18 Understanding Pacemaker Operations
9879EN-12_9501043EN/CTC.qxd 5/10/99 11:27 Page 12-18
7 x 9 inches (178 mm x 229 mm)
Medtronic Confidential
Refer to the “Reference man.” category in doc#163256 for Printing
Instructions.
196407001 Rev A