User Manual

ST Segment Analysis Arrhythmia and ST Analysis
4 - 12 0070-10-0690-01 Panorama™ Operating Instructions
Beat Detection and Typing
The following table describes the leads that are used for beat detection and beat typing.
The search for the next beat begins after a refractory period to avoid detecting T-waves as
valid QRS complexes. The minimum QRS amplitude that can be detected is between 0.15
mV and 0.45 mV depending on the width of the QRS complex.
Beat typing aligns and compares each new heart beat to reference templates that were
previously stored in the system. A beat typing algorithm classifies the beats.
• If an incoming beat matches a template that has already been classified, it is given the
same label as the template. The template parameters are updated with the features from
this new beat.
The real time ECG analysis library incorporates ventricular ectopic beat detection as a part
of arrhythmia analysis.
• Beats are measured for compensatory pause, QRS width, QRS positive and negative
areas, and R wave positive and negative amplitudes. This process uses multiple leads
when available.
• A scoring algorithm is then applied to those measurements to determine whether or not a
beat is ectopic.Beat detection and typing uses the monitored lead whenever a 3-wire lead
set is used.
4.3 ST Segment Analysis
The ST segment of an ECG waveform (shown in FIGURE 4-17) represents the period from the
end of ventricular de-polarization, to the beginning of ventricular re-polarization, or the end
of the QRS complex (the J point) and the beginning of the T-wave. ST Segment analysis is
used to monitor the oxygen supply and the viability of the heart muscle.
ST deviation is the vertical distance between the isoelectric (ISO) point level and signal level
at ST point.
The ISO point is located between the end of the P-wave and the onset of the QRS complex.
The ISO point provides the baseline for this measurement.
The ST point is a fixed distance from the J point at the end of the QRS complex. The ST point
can be configured to 40, 60, or 80 milliseconds past the J-point, independent of the heart
rate. By default, the ST point is positioned as follows:
• at 80 milliseconds for heart rates less than or equal to 120 beats per minute
• at 60 milliseconds for higher heart rates
DESCRIPTION 3-WIRE LEAD SET 5-WIRE LEAD SET VIEW 12
™
CARD
Leads used for Beat
Detection
Determined by viewed
lead
II and V V1 and V5
Leads used for Beat
Typing
Determined by viewed
lead
II, V, and I V1, V5, and II
Leads used for V-Fib
Detection
Determined by viewed
lead
II and V V1 and V5