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Lumax Technical Manual 87
The ICDs/CRT-Ds may be programmed to use ventricular-only
information, or both atrial and ventricular information for the
discrimination of ventricular tachyarrhythmias. With SMART
Detection™ turned ON, the Lumax ICDs/CRT-Ds use atrial and
ventricular signals for discrimination of fast heart rhythms. With
SMART Detection™ turned OFF, only the ventricular rate is used
to discriminate between ventricular rhythm classes. If SMART
Detection is enabled, this algorithm evaluates all cardiac signals
within the VT range and increments the VT Sample Count for all
intervals that are deemed VT. A full description of SMART
Detection™ is provided in Section
2.5.4.
In addition, when the Lumax senses the programmed number of
consecutive intervals (termination count) within the sinus rate
zone, all tachyarrhythmia detection criteria, including the VT
sample counters are reset.
2.5.4 SMART Detection™
DR and HF versions only
This discrimination algorithm enhances VT-1 and VT-2 detection
by applying a series of tests to the sensed cardiac signal. SMART
Detection™ is intended to discriminate VT from a variety of
supraventricular arrhythmias that are conducted to the ventricle
and that would otherwise satisfy VT-1 or VT-2 rate detection
criteria.
First, the average ventricular rate is compared to the average
atrial rate. In the event that the measured ventricular rate is faster
than the atrial rate, the device immediately declares the rhythm a
VT and delivers programmed ventricular therapy for the detected
VT zone.
In the event that an atrial rate is faster compared to the ventricular
rate one of three tests are performed:
Ventricular rhythm stability, (see Stability in Section
2.5.6 if the
ventricular signal is unstable, then the rhythm is declared a
supraventricular tachyarrhythmia, (SVT) and ventricular therapy is
typically withheld.
If the ventricular signal is stable, and the atrial rate is a multiple of
the ventricle rate, then the rhythm is declared a supraventricular
tachyarrhythmia (SVT) and ventricular therapy is typically
withheld.