User Manual Part 2

5-46
PACING THERAPIES
VENTRICULAR TACHY SENSING INTERACTIONS
Programming Considerations
Certain programmed combinations of pacing parameters are known to interfere
with ventricular tachy detection. The risk of ventricular tachy undersensing
due to device refractory periods is indicated by the interactive warnings on
the parameter screen.
As with all device programming, you should evaluate the benefits and the
risks o f the programmed features for eac h patient (for exam ple, th e ben efit
of Rate Smoothing with a long AV Delay versus the risk of ventricular tachy
undersensing).
The following programming recommendations a re provided to reduce the risk
of ventricular undersensing due to the refractory period caused by an atrial
pace (V-Blank after A-Pace):
• If a dual-chamber pacing mode with Rate Smoothing or Rate Adaptive
Pacing is necessary:
– Reduce the LRL
– Shorten the AV Delay or use Dynamic AV Delay and reduce the
minimum Dynamic AV Delay setting
– Reduce the percent AV Search Hystere sis
– Increase the Down Rate Smoothing percentage to the largest possible
value
– Decrease the recovery time for Rate Adaptive Pacing modes
– Reduce the MTR or MPR if Down Rate Smoothing is on
– Reduce the MSR if the pacing mode is rate adaptive
• If Rate Smoothing or Rate Adaptive Pacing are not required for the patient,
consider programming these features Off. Programming these features Off
can reduce the lik elihood of atrial pacing a t e levated rates.
• If atrial pacing is not required for the patient, consider using VDD rather
than DDD pacing mode.
- DRAFT -