QRS detector for defibrillator/monitor

摘要

A high-accuracy QRS detector detects "activity" on the ECG waveform. Activity results from a steep slope of one sense followed shortly thereafter by a steep slope of the opposite sense. Low-pass filtering activity and multiplying by 2.5 yields a noise threshold. An activity peak which rises above this threshold may be a QRS complex. The detector waits three-fourths the average R to R interval after detecting a peak to allow for greater peaks to be detected. If none are, the peak is confirmed if it is either at least half the magnitude of the previous peak, or if it occurs at least three-fourths the average R to R interval after the last detected peak. This high-accuracy detector may be coupled with a fast QRS detector by providing it with the peak values of the previous three detections. The fast detector will detect if the slope is greater than three-fourths the average of the previous three detections, greater than the noise threshold, and more than 160 ms has elapsed since its last detection.