Cardiac Science Powerheart AED G3 Plus 9390A Operator's And Service Manual page 33

Introduction
Non-committed shock
After the AED advises a shock, it continues to monitor the patient
ECG rhythm. If the patient's rhythm changes to a non-shockable
rhythm before the actual shock is delivered, the AED will advise that
the rhythm has changed and issue the prompt "RHYTHM
CHANGED. SHOCK CANCELLED." The AED will override the
charge.
Synchronized shock
The AED is designed to automatically attempt to synchronize shock
delivery on the R-wave if one is present. If delivery cannot be
synchronized within one second, a non-synchronized shock will be
delivered.
Pacemaker pulse detection
The AED contains pacemaker pulse detection circuitry to detect pulses
from an implanted pacemaker.
SVT discriminators
The AED is supplied with the SVT Discriminator enabled and with
the default setting "NO THERAPY FOR SVT". With the factory
default setting of "NO THERAPY FOR SVT", the AED will not
shock an SVT rhythm.
SVT Discriminators are sophisticated filters that analyze the
morphology of the ECG waveforms and distinguish VF/VT from SVT
and Normal Sinus Rhythms (NSR). The SVT Discriminator will only
be applied to rhythms that fall between the Detection Rate and the
SVT Rate. The factory default setting for this feature is "NO
THERAPY FOR SVT", however the Medical Director can enable this
feature using MDLink on the Powerheart AED.
SVT rate
All rhythms with rates between the Detection Rate and SVT Rate will
be screened through a number of SVT Discriminators to classify them
into VF/VT or SVT. Rhythms classified as SVT between the two set
rates are not shockable. All SVT rhythms above the rates will be
classified as shockable. The SVT Rate must be greater than the
70-00914-01 F Powerheart® AED G3 Plus 9390A and 9390E
2-4