User's Manual

Arrhythmia
9-5
Detecting Abnormal Beats
The system compares each incoming beat with the dominant class. It examines
morphology and the intervals between both the previous and following beats to
determine whether the beat does or does not match the dominant. If the system
determines the beat is abnormal, it compares the new beat with each of the
abnormal shapes categorized since the learn sequence was completed. If the
current beat fails to match any of the existing shapes (and after five occurrences),
the system classifies it as a new abnormal class.
Detecting Pauses
The system classifies an R-R interval that is 1.8 times (or 80%) longer than the
average R-R interval as a pause.
The last beat detected preceding the pause is displayed to the left of center in the
pause class. The system does not count two consecutive, long R-R intervals both
in the pause class. Instead, it assumes that a sudden rate change occurred and
updates the heart rate immediately.
Detecting Paced Beats
If the Paced mode is enabled in the ECG Setup menu and the system does not
detect a paced beat during the learn sequence, a paced class will be created once
the system detects the first paced beat.
The system identifies two different types of paced beats:
•paced
• AV-paced
The paced class is created for ventricular-paced beats defined as a QRS complex
which is preceded by a single pacemaker pulse.
The AV-paced class is created for beats that are preceded by two pacemaker
pulses.
The QRS complex must follow the pacemaker pulse within 150 msec for the beat
to be classified into either paced class. If the pacemaker pulse precedes the QRS
complex by more than 150 msec, the beat may be triggered by an atrial
pacemaker and is not classified in either paced class.
Relearning the Dominant Waveform
You can relearn the dominant rhythm and establish a new dominant at any time
during monitoring. After touching the RELEARN key, you can either clear the
memory or save the memory. Once a selection is made, the relearn sequence is
initiated during which ECG alarms are suspended. The old dominant is labeled as
exdominant and stored as an abnormal class.
WARNING:
• Until the patient’s rate and morphology are learned, ECG
alarms for high rate, low rate, run, couplet, abnormal per
minute, and tachycardia are not active.
To relearn the dominant
waveform:
1 Touch ECG.
2 Touch RELEARN.
3 Select SAVE MEMORY or
CLEAR MEMORY.