Cardiac monitoring system

• US 5,003,983 A
• Filed: 08/25/1988
• Issued: 04/02/1991
• Est. Priority Date: 08/25/1988
• Status: Expired due to Fees

• Current Assignee: Cortec Corporation
• Original Assignee: Cortec Corporation
• Inventors: Bellin, Howard T., Dingwall, Robert P.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US07/236,899
• Time in Patent Office: 950 Days
• Field of Search: 128/704, 128/703, 128/702, 128/696
• US Class Current: 600/517
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/358 Detecting ST segments

Abstract

A cardiac monitor system reads an EKG signal and conditions the EKG waveform in a manner that accentuates the information on ST segment location, within the waveform. ST segment location is used to modulate pulse width of a generated square wave permitting fast and accurate access to information regarding ST segment elevation and depression.

Claims

1. An apparatus for monitoring and converting an EKG waveform comprising electrical sensors for detecting said EKG waveform, a signal conditioning means in communication with said electrical sensors for inverting all negative portions of said detected EKG waveform, a pulse generator means including a low pass filter means for generating pulses having pulse width modulated by a change in location of a ST segment of said EKG waveform, and a comparator means for determining the amount of ST segment deviation from a normal value.

2. In an apparatus as in claim 1, further comprising output means including an alarm for indicating if said ST segment deviation has exceeded pre-selected limits.

3. In a system for monitoring a heart for the detection of abnormalities is an EKG signal apparatus comprising:

(a) signal acquisition means for detecting signal;

(b) signal conditioning means in communication with said signal acquisition means and comprising;

means for receiving said detected EKG signal;

signal adjustment means for normalizing said detected EKG signal; and

a signal inverting means for converting said normalized EKG signal into a DC signal; and

(c) pulse modulating means in communication with said signal conditioning means and comprising;

means for receiving said DC signal;

low pass filter means for processing said DC signal; and

pulse generating means generating an output pulse, wherein said output pulse is pulse width modulated by said processed DC signal.

4. The apparatus of claim 3, wherein said signal adjustment means further comprises an automatic gain control circuit with feedback control of said detected EKG signal.

5. The apparatus of claim 4, wherein said signal inverting means further comprises an inverting amplifier in parallel with a standard amplifier, wherein each amplifier is in series with a separate diode.

6. The apparatus of claim 5, wherein said pulse generating means comprises a gated pulse generating amplifier.

7. The apparatus of claim 6, wherein said gated pulse generating amplifier is adapted to receive a set point value, and compare said received C signal to said point value.

8. The apparatus of claim 7, wherein said gated pulse generating amplifier generates a pulse when said DC signal exceeds said set point value, and terminates said pulse when said DC signal drops below said set point value.

9. The apparatus of claim 8, wherein said gated pulse generating amplifier generates a square wave.

10. A method for detecting ST segment deviation comprising the steps of:

a) detecting an EKG waveform;

b) conditioning the EKG waveform by inverting all negative portions of said waveform to positive values and passing said inverted EKG waveform through a low pass filter;

c) generating a pulse wherein said pulse is modulated by the change in ST segment location of said EKG waveform; and

d) comparing said generated puls with a pulse modulated by an EKG waveform having a normal ST segment location.

11. The method of claim 10, wherein said conditioning the EKG waveform includes normalizing the gain in said EKG waveform.

12. The method of claim 10 further comprising the step of collecting plural pulses and determining an ST deviation based on time averaged changes in the pulses as generated.