User's Manual

71
Antitachycardia Functions
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Confirmation of 2:1 Lock-In
Detection of a 2:1 situation is determined as follows:
— The AV delay is lengthened for one cycle by a maximum of 300
ms, in order to confirm the 2:1 lock-in situation. In this manner,
events that previously fell within the blanking period are detected
by the implant as atrial refractory events. At the same time, the
minimum PVARP function is activated for the time of the AV
delay extension.
Termination
Termination is initiated as follows:
— If the As-Ars interval attains the mode switch rate, the implant
immediately switches to the previously selected ventricular mode
(without first waiting for the criteria for X/Z-out-of-8 mode
switching).
— If the rate that corresponds to the As-Ars interval is greater than
the mode switching rate, then the AV delay is reduced to the
current value in increments of 50 ms.
Programmable Parameters
The following parameter is displayed on Mode Switching screen, where
you can make the necessary settings.
2:1 Lock-in Protection
ON; OFF
PMT Management
The following features are provided for the prevention, detection, and
termination of pacemaker-mediated tachycardias (PMT):
PMT is prevented by
— Restarting the basic interval and the atrial refractory period
— Extending the atrial refractory period
PMT protection is offered by
— PMT detection
— PMT termination