BIOTRONIK Cardiac Airbag, Техническое руководство, Страница: 31 / 92

Cardiac Airbag Technical Manual 25
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U P P R E S S I O N
- The Enhanced T-Wave
Suppression setting is specifically designed to avoid double
counting of each QRS-T complex during normal sinus rhythms.
Two adjustments are made to ASC with this setting:
•
High pass filtering is increased to reduce low frequency
signal components such as T-waves and respiratory
artifacts.
•
The UT is increased to 75% of the measured R-wave.
•
The UT may not retrigger with each sensed event, it is
only triggered when the new sensed R-wave crosses the
50% point of the previous measured R-wave.
2.1.2 Minimum Ventricular Threshold
This parameter limits the minimum sensitivity of the ICD to
programmable value. Nominally, the minimum threshold is set to
0.8 mV, but it can be adjusted from 0.5 to 2.5 mV. a
entricular Tachyarrhythmia Detection
and deliver
signal to further differentiate ventricular
tachyarrhythmias. Each detected ventricular tachyarrhythmia is
clas
•
entricular Fibrillation
VF zone limit.
2.2 V
The Cardiac Airbag ICDs detect and measure the rate of sensed
cardiac signals to discriminate ventricular tachyarrhythmias from
sinus rhythm or sinus bradycardia. This is accomplished
through programmable rate detection parameters in the device.
When a tachyarrhythmia is present, the ICD classifies the
arrhythmia and delivers the appropriate therapy. If a
tachyarrhythmia continues following the first therapy attempt,
then the ICD will redetect the tachyarrhythmia
subsequent therapies as necessary.
Classification of cardiac signals is accomplished primarily by
measuring the cardiac cycle length (R-R intervals). In addition,
the ICD can also utilize abrupt changes in rate or irregularity of
the cardiac
sified into one of the following zones:
•
VT Ventricular Tachycardia Monitoring Zone
VF V
Each rhythm class is set to a separate rate with the zone limit
defining the lowest rate in each class. The upper rate limit of the
VT zone is equal to the