Del Mar Avionics, Inc.

Donald L Anderson

Isaac R Cherry

John A Ripley

W David Squires

David T Tanaka

Method and apparatus for arrhythmia analysis of Holter-type ECG recordings including a tape playback unit having an analog signal output of successive ECG complexes or heart beats, a converter for generating data composites representing each complex, a computer for making and storing data templates in bins corresponding to operator classification of complexes as normal, supraventricular ectopic (SVE), ventricular ectopic (VE), or unknown, for comparing successive composites with stored templates and conditions to determine a match condition, and for signaling a corresponding event to an event counter and display. In learn mode the computer signals the tape playback to stop and to display an unmatched complex for operator classification and possible subsequent generation of a new template, after which scanning is resumed.

Method and apparatus for arrhythmia analysis of ECG recordings

Apparatus is disclosed for long-term ambulatory monitoring of blood pressure by an auscultation method, employing a pressurizable cuff and requiring no intervention by the patient. Heartbeats are sensed by ECG electrodes, and a microphone is used to sense the Korotkow sounds as the pressure in the cuff is varied. The presence or absence of a Korotkow sound within a preset interval following each heartbeat is used in determining when the cuff pressure equals the systolic and diastolic pressures. Those pressures are determined in each cycle of operation and are recorded on a continuously-running portable tape recorder, along with the ECG signals. In each cycle of operation, the initial pressure to which the cuff is inflated is based on the systolic pressure measured in the immediately preceding cycle. The pressure in the inflated cuff is thereafter stepped downward in small discrete decrements triggered by successive heartbeats during the measurement phase of each cycle. After both the systolic and diastolic pressures have been determined, the remaining cuff pressure is vented through the same valve that was used to produce the stepwise pressure reduction. After a number of cycles of operation, the magnetic tape is removed from the portable recorder and inserted into an analyzer for high-speed playback and automated plotting of the heart rate and accompanying blood pressure readings on a common chart.

Blood pressure monitoring system

ECG signals from two approximately orthogonal leads are combined in a rectangular-to-polar coordinate converter to obtain signals representing the magnitude and angle of the vector. The vector angle existing at the instant the magnitude of the QRS vector reaches its peak is first identified, and a voltage corresponding to the vector angle is sampled and stored for later use. Secondly, the vector angle existing at the instant the magnitude of the T-wave vector reaches its peak later in the cardiac cycle, is identified, and a voltage corresponding to this second vector angle is sampled and stored. The voltages representing the QRS and the T-wave vector angles are then applied to a differential amplifier to obtain a difference voltage representing the angular difference existing between the two maximal vectors. This angular difference possesses certain characteristics which are diagnostically significant. A classifying circuit determines which one of a number of angular ranges the angular difference falls into. A counter is provided for each angular range to accumulate over successive heartbeats the number of differences which have fallen into each of the angular ranges, and the cumulative counts are displayed.

Method and apparatus for vector analysis of ECG arrhythmias

A miniature tape recorder intended for ambulatory recording of cardiac signals over a twenty-four-hour interval includes a clock with a visual display and an event marking circuit. Cardiac signals are recorded simultaneously on two tracks on the magnetic tape used by the recorder. The event marking circuit, activated by the patient, interrupts briefly the recording of cardiac signals on one of the tracks to record in its place an event marker signal easily recognizable on playback. The event marking circuit includes a clock circuit, a counter, and logic circuits to generate a burst of exactly eight square pulses of predetermined width, the duration of the burst being one second.

Recorder for cardiac signals with manually actuated event marking

A multi-speed ECG magnetic tape scanning device for processing and observing in a relatively short interval of time large quantities of ECG signals from two pairs of ECG leads. The ECG information is recorded on a miniature recorder which the patient carries to record the information for a long period of time, such as 24 hours. The recorder includes a built-in clock with a visible display. The recorder also includes an event marker, which is activated by the patient when the patient experiences an event. The play-back of the ECG information is in real time or at multiple high speed play-back speeds of 30, 60 and 120 times real time. During play-back at high speed, a multi-speed multi-channel paper writer reproduces analog trend data, digital printed data and event marking. The trend information is usually heart rate and ST segment level, so as to produce a scanning of an entire 24 hour information tape in as short a period as 12 minutes. The tape scanning device can run on trend to print out trend to the end of the tape, and then stop automatically. Alternatively, the tape scanning device can run on trend to the end of the tape and then automatically cycle to the beginning of the tape to print-out trend and periodically slow the tape down to real time for the print-out of predetermined events in real time. After each print-out in real time, the playback always goes back to the originally selected trend speed for the continuation of the trend print-out. Various short events may be used to slow the read-out to real time, such as an event marking on the tape which has been activated by the patient. Also, any preselected abnormalities in heart function such as abnormal VE's, SVE's, ST level, rapid heart beat, slow heart rate, etc., may be used to print-out in real time. An arrhythmia computer detects and digitally displays the number of premature ventricular contractions (VE) and superventricular ectopic beats (SVE) and actuates the event markers on a paper writer when the arrhythmia occurrences exceed a predetermined number of occurrences during a predetermined time interval. The event marking may also be used to control the slow down during trend read-out to print out the ECG signals in real time to show the arrhythmia occurrences. The arrhythmia computer includes the ability to select one or a number of parameters to determine the occurrence of an arrhythmia. These parameters may be paired beats, prematurity, width or amplitude.

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Huntington Beach, CA, United States of America

Donald L Anderson