Specifications

7 x 9 inches (178 mm x 229 mm)
Medtronic Confidential
Refer to the “Reference man.” category in doc#163256 for Printing
Instructions.
196407001 Rev A
Magnet Mode Operation
Overview
When the programming head (or other powerful magnet) is placed over the
pacemaker, an internal reed switch closes to initiate Magnet Mode
operation. Magnet application initiates a Threshold Margin Test and may
temporarily suspend the operation of specific features.
Magnet Mode Functions
When the magnetic reed switch closes during normal operations, the
pacemaker performs the following actions:
■
A Threshold Margin Test (TMT) is performed at 100 ppm, with pulse
width reduced by 25% on the third pacing cycle as a check for loss of
capture.
WARNING: Loss of capture during TMT indicates that the
stimulation threshold safety margin is inadequate. Immediately
perform a Pacing Threshold Test and reprogram outputs to establish a
2:1 voltage safety margin.
■
The pacemaker switches to an asynchronous mode and paces at the
magnet rate.
- Magnet modes are as follows: DOO in modes with dual chamber
pacing, VOO in the VDD mode, and VOO/AOO in single chamber
modes.
- Magnet rate for normal operation is 85 ppm for all modes.
- Magnet rate is 65 ppm when the Elective Replacement Indicator is
set or a full electrical reset has occurred.
■
Telemetry is enabled.
■
Diagnostic data collection is suspended.
16-2 Understanding Pacemaker Operations
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