Electrocardiogram filter

• US 6,823,209 B2
• Filed: 10/19/2001
• Issued: 11/23/2004
• Est. Priority Date: 10/19/2001
• Status: Expired due to Term

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Medtronic Physio-Control Corp. (Medtronic Plc)
• Inventors: Van Ess, David, Olson, Dana J., Schweizer, Scott O., Hart, Tyler R.
• Primary Examiner(s): Layno, Carl
• Application Number:
  US09/982,111
• Publication Number:
  US 20030078510A1
• Time in Patent Office: 1,131 Days
• Field of Search: 600/509-510, 600/513, 600/529, 607/9, 607/27-28
• US Class Current: 600/510
• CPC Class Codes: A61B 5/276 Protection against electrode failure
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

The invention presents techniques for identifying signals detected by electrodes on the body of a patient as part of a reading of the patient'"'"'s electrocardiogram. A signal processor digitally filters the signal from the body, resulting in an electrocardiogram signal and a signal that identifies the presence and timing of signals from a pacemaker in the body. Other signals, such as a signal that reflects the quality of the electrical connection of the electrode to the body, may also be obtained by digital filtering.

Claims

1. A device comprising:

a first digital filter that receives a digital signal representative of a signal from a body and generates a pacemaker signal as a function of pacing pulses supplied by a pace maker; and

a second digital filter that receives the digital signal and generates an electrocardiogram signal.

3. The device of claim 1, the second digital filter passes frequencies below 150 Hz.

4. The device of claim 1, further comprising a third digit filter that receives the digital signal and generates a signal indicative of the quality of the electrical connection of an electrode to the body.

5. The device of claim 4, wherein the third digital filter passes frequencies of 300 Hz.

6. The device of claim 1, further comprising:

an anti-aliasing filter that receives an analog signal from the body and generates a filtered analog signal; and

an analog-to-digital converter that receives the filtered analog signal and generates the digital signal.

7. The device of claim 6, further comprising:

a first electrode in contact with the body;

a second electrode in contact with the body; and

a difference amplifier that supplies the analog signal to the anti-aliasing filter as a function of the potential difference between the first electrode and the second electrode.

8. The device of claim 7, further comprising:

a third electrode in contact with the body;

a fourth electrode in contact with the body; and

a second difference amplifier that supplies a second analog signal to a second anti-aliasing filter as a function of the potential difference between the third electrode and the fourth electrode.

9. The device of claim 1, further comprising an analog-to-digital converter that receives a filtered signal and supplies the digital signal to the first digital filter and the second digital filter.

10. The device of claim 1, further comprising a processing system that includes the first digital filter and the second digital filter.

11. The device of claim 10, the processing system further comprising a digital signal processor that performs the functions of the first digital filter and the second digital filter.

12. The device of claim 1, further comprising a defibrillator that delivers a shock to the body as a function of the electrocardiogram signal.

2. The device of 1, wherein the first digital filter passes frequency components above 300 Hz.

13. A method comprising:

digitally filtering an electrical signal representative of a signal from a body to generate a pacemaker signal as a function of pacing pulses supplied by a pacemaker; and

digitally filtering the electrical signal to generate an electrocardiogram signal.

14. The method of claim 13, further comprising digitally filtering the electrical signal to generate a signal indicative of the quality of the electrical connection of an electrode to the body.

15. The method of claim 14, further comprising analyzing the electrocardiogram signal.

16. The method of claim 15, further comprising commencing a defibrillation sequence as a function of the analysis.

17. The method of claim 13, further comprising converting the electrical signal to a digital signal.

18. A device comprising:

an analog-to-digital converter that receives an electrical signal from a body and generates a digital signal; and

a processor that receives the digital signal and that digitally filters the digital signal to generate a pacemaker signal as a function of pacing pulses supplied by a pacemaker and digitally filters the digital signal to monitor an electrocardiogram signal.

19. The device of claim 18, further comprising an anti-aliasing filter that receives the electrical signal from the body and supplies a filtered electrical signal to the analog-to-digital converter.

20. The device of claim 19, further comprising:

a first electrode in contact with the body;

a second electrode in contact with the body; and

a difference amplifier that supplies the electrical signal to the anti-aliasing filter as a function of the potential difference between the first electrode and the second electrode.

21. The device of claim 20, further comprising:

a third electrode in contact with the body;

a fourth electrode in contact with the body; and

a second difference amplifier that supplies a second electrical signal to a second anti-aliasing filter as a function of the potential difference between the third electrode and the fourth electrode.

22. The device of claim 18, wherein the processor further digitally filters the digital signal to monitor the quality of an electrical connection of an electrode to the body.

23. The device of claim 18, further comprising an optical coupling that conveys the digital signal from the analog-to-digital converter to the processor.

24. The device of claim 18, further comprising a defibrillator that delivers a shock to the body as a function of the electrocardiogram signal.

25. A method comprising:

digitally filtering an electrical signal representative of a signal from a body to generate an electrocardiogram signal; and

simultaneously digitally filtering the electrical signal to generate a second patient signal.

26. The method of claim 25, wherein the second patient signal is one of a pacemaker signal as a function of pacing pulses supplied by a pacemaker, a signal indicative of the quality of the electrical connection of an electrode to the body, a signal as a function of respiration and a signal as a function of telemetry signals supplied by a device implanted in the body.