User's Manual

76
Antitachycardia Functions
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Figure 16: Incremental rate reduction with preventive overdrive pacing
Safety Function of the Algorithm
Preventive overdrive pacing provides various safety functions which
are, for example, effective for high atrial rates:
• When the programmed maximum overdrive rate (MOR) is exceeded,
such as in the case of atrial tachycardias, then the algorithm is
automatically deactivated. Should the rate fall below the MOR, the
overdrive algorithm is reactivated.
• The function is likewise deactivated when the average atrial rate of
the last 64,000 cycles exceeds the average safety rate (ASR). In this
case, the pacing rate is incrementally decreased to the basic rate.
The ASR is dependent on the programmed basic rate and the MOR.
When the average atrial heart rate falls below the ASR, preventive
overdrive pacing is reactivated.
The overdrive remains permanently switched off after the fourth
deactivation due to the ASR being exceeded. The overdrive mode can
be reactivated only after the next interrogation of the pacemaker.