User's Manual

41
Timing Functions
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Rate range AV delay (in ms) for
programming the dynamic AV
delay to
Low Medium High
Basic rate (for non-
rate-adaptive modes)
180 180 180
Less than 70 ppm 180 180 180
70 - 90 ppm 170 160 150
91 -110 ppm 160 140 120
111 - 130 ppm 150 120 100
Over 130 ppm 140 100 75
Table 3: Dynamic AV delays
The dynamic AV delay serves to prevent pacemaker-mediated
tachycardias and supraventricular tachycardias. See also the
"Antitachycardia Functions" section.
AV Hysteresis
An AV hysteresis can be programmed to a low, medium or high setting
to promote intrinsic AV conduction. With AV hysteresis active, the AV
delay is extended by a defined time period after sensing an intrinsic
ventricular event. The long AV interval remains intact as long as an
intrinsic ventricular activity is measured during the extended AV delay.
The short AV delay interval without extension by the hysteresis value
follows after ventricular pacing.
Caution! If AV hysteresis is enabled along with the algorithm
for detecting and terminating pacemaker-mediated
tachycardias (PMT Management), the variations in
the AV delay for detection and termination of a
PMT have priority over any possible simultaneous
activation of the AV hysteresis.