American Optical Corporation

Richard Paul Andresen

Robert L Cannon, Iii

Andrew J Griffin

Robert M Armington

An improved R-wave detector is provided for use in monitoring and/or analyzing electrical heart waveforms. Generally conventional R-wave detection means employ automatically variable scaling means for providing a threshold or reference value to a comparator which is variable not only in magnitude but also as a percentage of the average R-wave peak value from which it is derived. An ECG waveform is compared with this threshold of automatically variable percentage value and an indication of R-wave occurrence is provided when the ECG waveform exceeds the threshold. Upon an indication of R-wave occurrence, the percentage value of the threshold is rapidly increased such that a closely following T-wave of unusually large magnitude is not falsely detected as an R-wave. Then, following the interval during which a T-wave might occur and before the possible occurrence of even a premature following R-wave, the percentage value of the threshold decreases to a level capable of detecting even such premature R-waves of reduced amplitude.

Variable threshold R-wave detector

Apparatus for the recognition of ventricular premature beats by an identifying width of a QRS complex by dividing the area by the height and further noting when the width measurements is at least 40% wider than the average width of the immediately preceding several QRS complexes. Additional apparatus for indicating ventricular premature beats by determination of an early width determination which exceeds the average width by at least 20% and is additionally followed by the compensatory pause as determined by interbeat interval measurement.

Method and apparatus for monitoring electrocardiographic waveforms

A system for the cyclical time-compression of a continuous physiologic waveform provides scan-type display without loss of data during retrace by recording original data at one rate during a retrace-trace cycle, and read-out at a faster rate during the trace period for the compressed display. A feature of the system is use of a single random-access memory which has only the relatively small capacity for storing the data entered from the beginning of the retrace in a time compression cycle until readout at trace period in that cycle begins.

Time-compression system

An improved graphical recorder display system for obtaining an accurate record of one or more sensed and displayed parameter values, such as associated with one or more vital signs of a patient. The system includes a writing surface medium, such as a chart paper on a drum; means for advancing the writing surface medium relative to a galvanometer pen means, the pen means being adapted for scribing on the writing surface in a direction transverse to the direction of relative advance of the chart paper; means for generating time-incremented electrical signals for extension to the galvanometer pen means during a predetermined period for scribing a graticule on the chart paper; means, such as a dither signal, selectively extendible to the galvanometer pen means for scribing one or more cursors on the chart paper; and means providing control signals representative of one or more respective vital sign parameter values for controlling the application of the dither signal to the galvanometer pen means such that the resulting cursors are in accurately timed relation to the graticule. The dither signal is available in different amplitudes for selection by respective different parameter value signals such that the scribed cursor associated with the respective parameter values differ from one another in appearance. Further, the intensity of the scribed trace may be varied.

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Arlington, MA, United States of America

Richard Paul Andresen