Saadat ALBORZ B9, Руководство оператора

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Chapter 6: Arrhythmia Monitoring User Manual
6-3
Arrhythmia detection algorithm principle
The arrhythmia algorithm is based on template matching. (A template is a group of beats
matching the same morphology). The algorithm detects QRS complexes, generates QRS
templates and performs beat labelling. This algorithm is divided into three parts: detector,
classifier and labelling.
The detector algorithm detects waves in ECG signal that could be QRS complexes.
The classifier algorithm forms templates of similar QRS complexes. During the learning phase
an initial set of QRS template is built. Then the monitor creates a reference template based on its
identification of the patient’s dominant QRS pattern. When a new true QRS complex is detected,
it is compared with the existing templates. If no match is found, a new QRS template is added to
the template set.
The labelling algorithm analyses all templates. Each template and the beats belonging to it are
labelled with one of the following names: normal beats, ventricular beats and questionable beats.
Through this process, the monitor can verify a
n arrhythmia event’s occurrence.
Parallel to this process there is an algorithm for detection of ventricular fibrillation.
Detection of ventricular fibrillation is based on waveform analysis. AFIB arrhythmia is detected
through obtained parameters in the previous parts and analysis of R-R intervals. Maximum one
minute after occurring AFIB arrhythmia, related alarm will be activated and time of arrhythmia
occurrence will be recorded in the Trend window.
Beat and rhythm classification
Beat clas sification refers to the analysis of individual beats. If the new beat’s features do not
match those of the normal template, the new beat is classified as premature or questionable.
The monitor uses all detected beats to calculate the heart rate, eliminating questionable beats
from arrhythmia classification.
Rhythm classification refers to analysis of sequences of beats. The monitor compares the
sequence of the last twelve beats with the sequences stored in the monitor’s memory. If it detects
two or more events simultaneously, the monitor alarms in order of event priority.