ECG, arrhythmia, and ST segment
226
Instructions for use – Infinity Acute Care System – Monitoring Applications VG6.n
Monitoring ST overview
ST analysis examines normal QRS complexes
from up to 12 ECG leads. The M540 learns each
ST lead, combines the measurements into an
average QRS complex, and derives the ST
segment deviation. ST monitoring is available for
adult and pediatric patients.
The ST segment deviation is defined as the
displacement (in mm or mV) above or below the
isoelectric line. The deviation measurement
compares the isoelectric point to the ST
measurement point. The following figure identifies
the measured elements of a QRS complex.
A
Fiducial point
B
ST level
C
ST measurement point
D
QRS offset
E
QRS onset
F
Isoelectric point
Refer to the instructions for use
Infinity Acute Care
System – Infinity M540
for a detailed description of
the M540 ST functions.
The ST monitoring functions are configurable on
parameter-specific setup pages (see page 234).
Before performing any monitoring functions, refer
to the section “For your safety and that of your
patients“on page 13.
Standard ST monitoring
The 6-wire lead set monitors eight ECG leads, of
which two are chest leads (V and V+). 12-lead ST
analysis provides the most comprehensive view of
a patient’s condition. However, with optimal
placement of the V and V+ leads and using only
eight leads, you can achieve an ST analysis that is
almost as comprehensive but with fewer
electrodes.
326
A
B
C
D
E
F
NOTE
ST analysis is always performed using a
dedicated filter which ensures diagnostic quality.
The ECG filter settings (
ESU
,
Monitor
, and
Off
)
are not of diagnostic quality, and as a result, the
ST segment of the ECG waveform may appear
differently from the ST segment of the ST
complex. An ECG report is not of diagnostic
quality. Therefore, the ST segment of the ECG
waveform on the report may appear differently
from the ST segment of the ST complex. The only
report of ECG diagnostic quality is a Rest ECG
report.
