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Lumax Technical Manual 113
2.9.8.2 Post Mode Switch Response
Whenever Mode Switching event terminates, deactivating the
mode switch pacing, the device can be programmed to react with
a different basic rate for a specified amount of time. Two
parameters are used to set the Post Mode Switch Response.
Post ModeSw Rate sets the rate difference (from permanent
program) in pacing rate during the programmed Post ModeSw
Duration time period. After the Post ModeSw Duration expires,
the pacing rate is ramped down to the programmed basic rate.
2.9.9 PMT Management
A PMT is defined as a tachycardia caused by inadvertently
tracking retrograde P-waves. The PMT management feature
includes PMT Protection/Termination and a programmable PMT
detection and termination algorithm.
2.9.9.1 Protection
PMT
protection is accomplished by the following mechanisms
(see Figure 12
):
Upon detection of a ventricular extrasystole (VES), the
lower rate interval and the atrial refractory period (ARP)
are reset. Additionally, in VDD mode, the atrial refractory
period is initiated with a ventricular pacing pulse that has
not been triggered by atrial detection. This prevents a
retrograde P-wave with a VA conduction time shorter
than the ARP from being sensed and thus from triggering
a ventricular pacing pulse. This provides an automatic
PMT protection.
A programmable atrial refractory period extension
(ARPE) is available in the DDD and VDD modes. To
prevent the initiation of a pacemaker mediated
tachycardia (PMT) by a ventricular depolarization not
preceded by an atrial depolarization, the ARP will be
extended by the ARPE if the ARP was:
o started by a ventricular sense event outside of the AV
delay (e.g., PVC) in DDD and VDD or
o reset by a ventricular pulse not triggered by an atrial
sense event in VDD.