User's Manual

2. Verify magnet function and telemetry to ensure the pulse generator is within acceptable range.
3. Program the appropriate parameters and change the pulse generator Tachy Mode to Monitor + Therapy.
4. Perform the induction using the programmer.
Determine DFT
Defibrillation threshold (DFT) testing should be performed at implant to ensure adequate safety margins for the
shock energy (safety margin = device maximum shocking energy minus DFT). The DFT is the minimum energy
tested that reliably converts VF or polymorphic VT in a series of arrhythmia trials with decreasing energy steps.
To determine DFT, induce VF (or PVT or ventricular flutter if VF is not inducible). Attempt to convert the
arrhythmia with a 31-J shock; if conversion is successful, then induce again and attempt to convert the
arrhythmia at 29 J. Continue in this manner, decreasing the energy level until failure to convert VF occurs or 3 J
is successful. If the initial conversion at 31 J is unsuccessful, reposition the lead, or reverse polarity, or add an
additional lead. The energy level that last successfully converted the arrhythmia is the DFT. It is a matter of
clinical judgment as to what constitutes a demonstration of reliable conversion.
Shocks intended for VF therapy should be programmed with a 10 J safety margin above the shock energy
level that the physician determines is required for successful VF conversion. In some situations an alternative
safety margin may be determined by the physician to be adequate above the shock energy level required
for successful VF conversion.
NOTE: Since the results of any single test may be an example of statistical variation, a one-time conversion of
a rhythm disturbance at a particular energy level does not guarantee or assure that the energy level is reliable
for conversion. As a safety margin, it is recommended that you perform the conversion test at the DFT two
times if the DFT is 31 J, or one time if the DFT is 29 J with no failures to convert.
Step J: Implant the Pulse Generator
1. Program the Tachy Mode to Off.
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