Memory loop ECG recorder with LIFO data transmission

• US 5,339,824 A
• Filed: 10/06/1992
• Issued: 08/23/1994
• Est. Priority Date: 10/06/1992
• Status: Expired due to Fees

• Current Assignee: Cardiac Evaluation Center, Inc. (SHL Telemedicine Ltd.)
• Original Assignee: Cardiac Evaluation Center, Inc. (SHL Telemedicine Ltd.)
• Inventors: Engira, Ram M.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US07/957,545
• Time in Patent Office: 686 Days
• Field of Search: 128/712, 128/696, 128/702, 128/705, 128/709, 128/710, 128/903, 128/904
• US Class Current: 600/525
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/336 Magnetic recording apparatus
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A memory loop recorder records electrocardiographic data in a random access memory for transmission to a remote display terminal via telephone line. The ECG data in the loops is transmitted in reverse time-order to the display from a point related to the occurrence of symptoms. The remote display terminal displays the transmitted data from right to left thus correcting the time access of the graphical display but allowing more rapid diagnosis of the critical ECG data.

Claims

1. An apparatus for monitoring and transmitting electrocardiographic data from a patient to a remote display terminal comprising:

an acquisition means for communication at least one electrocardiographic signal having a time-varying amplitude providing the electrocardiographic data from the patient to the apparatus;

a digitizing means communication with the acquisition means for receiving and sampling the electrocardiographic signal at a plurality of instants in time to produce samples and further digitizing the samples of the electrocardiographic signal to produce a set of time-ordered digital words indicating the amplitude of the electrocardiographic signal at the plurality of instants;

a storage means communicating with the digitizing means for receiving and storing the digital words according to their associated sampling instants in time;

an episode marker means, communicating with the storage means, for designating one instant as a transmit instant; and

a transmission means communicating with the storage means for reading the digital words in sequence from the transmit instant in reverse time-order and transmitting the read digital words to the remote display terminal.

2. The apparatus as recited in claim 1 wherein the episode marker means, includes a patient accessible switch communicating with the storage means to be activated at a time during the storage of the digital words and the episode marker means designates as the transmit instant and instant associated with a digital word being stored at the time of activation of the switch.

3. The apparatus as recited in claim 1 wherein the episode marker means, includes a patient accessible switch communicating with the storage means to be activated at a time during the storage of the digital words and the episode marker means designates as the transmit instant an instant removed in time by a predetermined amount from the instant associated with a digital word being stored at the time of activation of the switch.

4. The apparatus recited in claim 1 wherein the storage means in partitioned into at least one event loop containing a predetermined number of addresses at which digital words may be stored and wherein the digital words are stored in sequence from a first address to a last address after which the stored digital words are replaced by new digital words stored in sequence from the first address to the last address.

5. The apparatus of claim 1 wherein the acquisition means ia radio transmitter and receiver pair for communication the electrocardiographic signal from the patient to the digitizing means.

6. The apparatus of claim 5 wherein the transmission means is a modulator means for modulating an audio carrier for transmission on a telephone line.

7. The apparatus of claim 1 wherein the acquisition means is a set of electrical conductors adapted to be attached between the patient and the digitizing means.

8. The apparatus of claim 1 wherein the transmission means is a modulator means for modulating an audio carrier for transmission on a telephone line.

9. The apparatus as recited in claim 1 wherein the transmission means transmits the digital words in sequence from the transmit instant in reverse time-order so that every word transmitted is transmitted in reverse time order.

10. An apparatus for monitoring and transmitting electrocardiographic data from a patient to a remote display terminal comprising:

an acquisition means for communication at least one electrocardiographic signal having a time varying amplitude providing the electrocardiographic data from the patient to the apparatus;

a digitizing means communication with the acquisition means for receiving and sampling the electrocardiographic signal at a plurality of instants in time to produce samples and further digitizing the samples of the electrocardiographic signal to produce a set of time-ordered digital words indicating the amplitude of the electrocardiographic signal at the plurality of instants;

a storage means communication with the digitizing means for receiving and storing the digital words according to their associated sampling instants in time;

an episode marker means, communicating with the storage means, for designating one instant as a transmit instant; and

a transmission means communicating with the digitizing means and the storage means for transmitting to the display terminal the time-ordered digital words at the plurality of instants as real time data and for reading the digital words in sequence from the transmit instant in reverse time-order and also transmitting the read digital words as recorded data.

11. The apparatus of claim 10 wherein the acquisition means is a set of electrical conductors adapted to be attached between the patient and the digitizing means.

12. The apparatus of claim 10 wherein the acquisition means is a radio transmitter and receiver pair for communicating the electrocardiographic signal from the patient to the digitizing means.

13. A system for monitoring, transmitting, and displaying electrocardiographic data from a patient comprising:

an acquisition means for communication at least one electrocardiographic signal having a time varying amplitude providing the electrocardiographic data from the patient to the apparatus;

a digitizing means communication with the acquisition means for receiving and sampling the electrocardiographic signal at plurality of instants in time to produce samples and further digitizing the samples of the electrocardiographic signal to produce a set of time-ordered digital words indicating the amplitude of the electrocardiographic signal at the plurality of instants;

a storage means communicating with the digitizing means for receiving and storing the digital words according to their associated sampling instants in time;

an episode marker means, communicating with the storage means, for designating one instant as a transmit instant;

a transmission means communicating with the digitizing means and the storage means for transmitting the time-ordered digital words in a transmission order at the plurality of instants as real time data, and for reading the digital words in sequence from the transmit instant, in reverse time-order and transmitting the read digital words as recorded data in a transmission order; and

a remote display terminal for receiving the transmitted real time data and recorded data

wherein the display terminal displays the real time data and recorded data as data points in graphical form with a first and second parallel abscissa indicating time and a first and second ordinate indicating the amplitude of the electrocardiographic data associated with the data points, for the real time data and recorded data respectively, and

wherein the data points of real time data are written across the display in a first direction along the first abscissa with respect to their transmission order and wherein the data points of the recorded data are written across the display in a second direction opposite to the first direction along the second abscissa with respect to their transmission order.

14. A display apparatus for simultaneously displaying real time electrocardiographic data received in time-order and recorded electrocardiographic data received in reverse time-order, the display apparatus comprising:

a computer/interface system including input interface circuitry means for receiving the real time electrocardiographic data and recorded electrocardiographic data according to a respective transmission order and output interface circuitry means for generating in response to a computer operating in accordance to a stored program, a plurality of data points for each datum having ordinate values related to the value of the datum, and abscissa values related to the relative instants of time associated with each datum so that the abscissa values for the data points of the real time data are proportional to their transmission order and wherein the abscissa values of the data points of the recorded data are proportional to the negative of their transmission order; and

a user readable screen receiving the data points and displaying the data points at the abscissa and ordinate values.

15. An apparatus for monitoring, transmitting, and displaying electrocardiographic data from a patient comprising:

electrode means for receiving an electrocardiographic signal having a time varying amplitude providing the electrocardiographic data from the patient to the apparatus;

a memory means having addresses and communicating with the electrode means for receiving and storing the electrocardiographic data, wherein the memory means is partitioned into at least one event loop containing a predetermined number of addresses at which digital words may be stored and wherein the digital words are stored in sequence from a first address to a last address after which the stored digital words are replaced by new digital words stored in sequence from the first address to the last address;

a user activated switch means communicating with the memory means for designating one instant as a transmit instant wherein the transmit instant is an instant removed in time by a predetermined amount from the instant associated with a digital word being stored at the time of activation of the switch means;

a transmission means communicating with the memory means for reading the digital words in sequence from the transmit instant and transmitting the read digital words;

a remote terminal having a display means for receiving the read transmitted digital words and for displaying the read transmitted digital words and an inputting means for inputting input data and transmitting the input data to the apparatus; and

a reception mans for receiving a value of at least one of the predetermined amount and the first and last address from the remote terminal.