Abstract:
An electrocardiographic patient lead cable apparatus comprises an elongated cable part and a connector. The cable part has a plurality of connecting wires with connectors for the electrodes. The connecting wires are joined together for varying portions of their length to form a flat common portion of the cable part. The common portion is connected at one end to the connector. The connecting wires separate from the common portion at the selected locations along the extension of the common part from the end connected to the connector to form relatively short separated connecting wires. The lead cable apparatus so formed facilitates correct connection of electrodes positioned at various locations on the body of the patient and reduces or eliminates tangling of the connecting wires. The connector is of compact, lightweight construction.
Abstract:
A low power pulse oximeter includes an input stage for amplifying a signal received from a light detector that is switchably connected to the power supply that powers the amplifier. The oximeter also includes an output stage with an LED driver circuit that is switchably connected to the power supply that powers the LED driver circuit. The input and output stages are switchably connected to the power supply when measurements need to be taken. When measurements do not need to be taken, they are switched off to reduce the power consumption of the oximeter.
Abstract:
Disclosed herein is a method and apparatus employing a D.C. drive motor and digital printhead for recording electrocardiographic data or other digital data on a chart at a constant time scale, regardless of temporary variations in the D.C. motor speed. A buffer memory stores sensed digital ECG data, and a data count register provides a count indicative of the amount of data stored. A pulse width register controls the width of long and short pulses generated by a motor driver for the selected paper speed. An experience count register has a count indicative of the relative number of long and short pulses generated. The original or current width of the pulses may be adjusted by the pulse width register, subject to the count of the experience count register, for controlling the speed of the D.C. drive motor. The motor speed is increased if the buffer memory is storing more than a preselected amount of data, and the motor speed is decreased if the buffer memory is storing less than a preselected amount of data. Means, including a tach count register, regulate the output of ECG data from the buffer memory to the digital printhead for recording at a rate proportional to the speed of the D.C. drive motor, to produce a constant time scale chart record of such data, regardless of temporary variations in the D.C. motor speed.
Abstract:
An analog-to-digital converter (ADC) controlled in a manner to increase its precision. The signal to be digitized is one input to an analog signal summing means whose output is the input to the ADC. A stepped or dither voltage signal is applied to the other summing means input during each analog signal sampling period of the ADC. The dither voltage steps are equal to the voltage equivalent of one ADC count plus 1/N where N is the number of steps per ADC count chosen to obtain a desired degree of precision in the digital signals that are output by the ADC. The dither voltage step that is combined with the current analog signal sample in the summing means amounts to displacing the sample in steps within each count of the ADC. The ADC converts each combined signal during a sampling interval to a succession of binary digital values which are summed. The result of the summation is a binary number having a value that corresponds more precisely to the true value of the analog signal samples than would be the case if they were converted directly by the ADC.
Abstract:
A waveform processor for processing waveforms of the ECG type from surface electrodes connected to the human body. Differential lead waveforms are sampled by a fast, high resolution A/D converter which are thereafter provided to a preprocessor where filtering and a reconstruction of the leads waveforms takes place. The waveforms are then detected, classified, and averaged to form composites of the X, Y, and Z terminal leads. Special filtering is used to detect the high frequency low amplitude features of the composite waveforms.
Abstract:
An apparatus and method directed to an adaptive noise filtering arrangement. The arrangement has the ability to estimate a first set of data for a first time-dependent variable based upon at least two sets of data for two time-dependent variables related to the first time-dependent variable. Additionally, the arrangement has the ability to filter an actual set of data for the first time-dependent variable based upon the first set of data and the actual set of data. The estimated first set of data and filtered actual set of data can be printed or displayed in a graphical format for analysis.
Abstract:
An apparatus and method directed to an adaptive noise filtering arrangement. The arrangement has the ability to estimate a first set of data for a first time-dependent variable based upon at least two sets of data for two time-dependent variables related to the first time-dependent variable. Additionally, the arrangement has the ability to filter an actual set of data for the first time-dependent variable based upon the first set of data and the actual set of data. The estimated first set of data and filtered actual set of data can be printed or displayed in a graphical format for analysis.
Abstract:
A method and means for graphically recording electrocardiographic data reduces the amount of redundant data displayed so as to reduce the size of the electrocardiogram. However, arrhythmias and other aberrant ekg signal complexes are reproduced in context for diagnostic purposes. Typical or normal signal complexes received from the patient are used to establish an ekg signal complex pattern. In the absence of aberrant signal complexes, this pattern is recorded in lieu of the patient data at a speed which is less than the normal recording speed to form the electrocardiogram. One such pattern may be recorded for every 25 complexes in the patient data, thereby achieving the reduction in the size of electrocardiogram. When an aberrant signal complex occurs, it is entered in the electrocardiogram at the normal higher recording speed. For repetitiously occurring aberrant signal complexes, only certain occurrences of such aberrancies are entered in the electrocardiogram. The proportionality of aberrant to normal signal complexes appearing in the electrocardiogram is thus maintained the same as that appearing in the electrocardiographic data from the patient.
Abstract:
A method of identifying and measuring altemans in an electrocardiographic (ECG) signal representative of the electric activity of a heart of a patient. The ECG signals from the patient are divided into individual cardiac cycles and the amplitude of four segments of the repolarization portion and the depolarization portion of each cardiac cycle are measured. The amplitude for each of the repolarization segments are measured from a reference baseline that is determined by a first base segment occurring immediately prior to the repolarization portion of the present cardiac cycle and a second base segment occurring immediately before the depolarization portion of the next cardiac cycle in the sequence. Based upon the amplitude measurements over the repolarization and the depolarization portions of each cardiac cycle, digital signal processing is applied to the measurements to generate eigenvariables. A spectral density is calculated for each of the eigenvariables, which spectral densities can be used to determine both the presence of altemans and the respiratory frequency.