Implantable cardiac stimulation device, system and method which provides an electrogram signal having the appearance of a surface electrocardiogram

• US 6,658,283 B1
• Filed: 09/25/2001
• Issued: 12/02/2003
• Est. Priority Date: 09/25/2001
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Florio, Joseph J., Bradley, Kerry, Bornzin, Gene A.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US09/963,207
• Time in Patent Office: 798 Days
• Field of Search: 607/1-28, 600/508-521
• US Class Current: 600/510
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

An implantable cardiac stimulation system and method provides an external display of a heart activity signal sensed internally by an implantable cardiac stimulation device which has the appearance of a surface EKG. The heart activity signal is sensed by the implanted device and is processed by the device or the external display to have frequency characteristics resembling that of a surface EKG. The heart activity signal to be displayed takes the form of an intracardiac electrogram signal with a low frequency roll-on of no greater than 0.4 Hz and a high frequency cutoff of no less than 20 Hz. This provides a heart activity signal for display which has the appearance and most attributes of a surface EKG.

Claims

1. In an implantable cardiac stimulation system comprising an implantable cardiac stimulation device and an external display device, the system providing a heart activity signal of a heart for display having the appearance of a surface electrocardiogram, the system comprising:

at least one implantable electrode that senses cardiac electrical activity and provides an intracardiac electrogram signal; and

a filter that filters the intracardiac electrogram signal with a low frequency cutoff of no greater than about 0.4 Hz and a high frequency cutoff of no less than about 20 Hz to provide the heart activity signal for display;

wherein the external display device comprises the filter.

2. The system of claim 1 wherein the implantable cardiac stimulation device comprises a telemetry circuit that transmits the heart activity signal to the external display device for display of the heart activity signal.

3. The system of claim 2 wherein the implantable cardiac stimulation device comprises a memory that stores the heart activity signal prior to transmission of the heart activity signal.

4. The system of claim 1 wherein the external display device comprises a memory that stores the heart activity signal prior to displaying the heart activity signal.

5. The system of claim 1 wherein the implantable cardiac stimulation device comprises a telemetry circuit that transmits the intracardiac electrogram signal to the external display device for filtering and display and wherein the external device comprises a receiving circuit that receives the intracardiac electrogram signal from the implantable cardiac stimulation device.

6. The system of claim 5 wherein the implantable cardiac stimulation device comprises a memory that stores the intracardiac electrogram signal prior to transmitting the intracardiac electrogram signal to the external display device.

7. The system of claim 5 wherein the external display device comprises a memory that stores the intracardiac signal prior to filtering and display.

8. The system of claim 1 wherein the filter is a high pass filter.

9. The system of claim 1 wherein the filter is a digital filter.

10. The system of claim 9 wherein the digital filter is an equalizer.

11. The system of claim 1 wherein the at least one electrode is adapted for implant in or proximal to an atrium of the heart.

12. The system of claim 1 wherein the at least one electrode is adapted for implant in the right atrium of the heart.

13. The system of claim 1 wherein the at least one electrode is adapted for implant in or proximal to a ventricle of the heart.

14. The system of claim 1 wherein the at least one electrode is adapted for implant in the right ventricle of the heart.

15. The system of claim 14 wherein the implantable cardiac stimulation device comprises a ventricular defibrillator and wherein the at least one electrode is a right ventricular defibrillation electrode.

16. The system of claim 1 wherein the at least one electrode comprises a first electrode adapted for implant in or proximal to an atrium of the heart and a second electrode adapted for implant in or proximal to a ventricle of the heart.

17. The system of claim 1 wherein the at least one electrode comprises a first electrode adapted for implant in the right atrium of the heart and a second electrode adapted for implant in the right ventricle of the heart.

18. In an implantable cardiac stimulation system comprising an implantable cardiac stimulation device and an external display device the system providing a heart activity signal of a heart for display having the appearance of a surface electrocardiogram, the system comprising:

sensing means for sensing cardiac electrical activity and providing an intracardiac electrogram signal; and

filter means for filtering the intracardiac signal with a low frequency cutoff of no greater than 0.4 Hz and a high frequency cutoff of no less than 20 Hz for providing the heart activity signal for display;

wherein the external device comprises the filter means.

19. The system of claim 18 wherein the implantable cardiac stimulation device comprises telemetry means for transmitting the heart activity signal to the external device for display of the heart activity signal.

20. The system of claim 19 wherein the implantable cardiac stimulation device comprises memory means for storing the heart activity signal prior to transmission of the heart activity signal.

21. The system of claim 20 wherein the external device comprises memory means for storing the heart activity signal prior to displaying the heart activity signal.

22. The system of claim 18 wherein the implantable cardiac stimulation device comprises telemetry means for transmitting the intracardiac electrogram signal to the external device for filtering and display and wherein the external device comprises receiving means for receiving the intracardiac electrogram signal from the implantable cardiac stimulation device.

23. The system of claim 22 wherein the implantable cardiac stimulation device comprises memory means for storing the intracardiac electrogram signal prior to transmitting the intracardiac electrogram signal to the external device.

24. The system of claim 22 wherein the external device comprises memory means for storing the intracardiac signal prior to filtering and display.

25. The system of claim 18 wherein the filter means comprises a high pass filter.

26. The system of claim 18 wherein the filter means comprises a digital filter.

27. The system of claim 26 wherein the digital filter is an equalizer.

28. The system of claim 18 wherein the sensing means comprises at least one electrode adapted for implant in or proximal to an atrium of the heart.

29. The system of claim 18 wherein the sensing means comprises at least one electrode adapted for implant in the right atrium of the heart.

30. The system of claim 18 wherein the sensing means comprises at least one electrode adapted for implant in or proximal to a ventricle of the heart.

31. The system of claim 18 wherein the sensing means comprises at least one electrode adapted for implant in the right ventricle of the heart.

32. The system of claim 31 wherein the implantable cardiac stimulation device comprises a ventricular defibrillator and wherein the sensing means comprises at least a right ventricular defibrillation electrode.

33. The system of claim 18 wherein the sensing means comprises a first electrode adapted for implant in or proximal to an atrium of the heart and a second electrode adapted for implant in or proximal to a ventricle of the heart.

34. The system of claim 18 wherein the sensing means comprises a first electrode adapted for implant in the right atrium of the heart and a second electrode adapted for implant in the right ventricle of the heart.

35. In an implantable cardiac stimulation system comprising an implantable cardiac stimulation device and an external display device, a method of providing a heart activity signal of a heart which, when displayed, resembles a surface electrocardiogram, the method comprising:

sensing cardiac electrical activity with at least one implanted electrode to provide an intracardiac electrogram signal; and

filtering the intracardiac signal with a high pass filter having a low frequency cutoff of no greater than 1 to 2 Hz and a high frequency cutoff of no less than 20 Hz;

transmitting the filtered intracardiac signal to the external display device;

further filtering the filtered intracardiac signal with an equalizing filter to resemble a surface electrocardiogram, the further filtering step performed within the external display device.

36. The method of claim 35 comprising the further step of storing the heart activity signal in a memory prior to transmitting heart activity signal to the external display device.

37. The method of claim 36 comprising the further step of storing the heart activity signal within the external display device prior to displaying the heart activity signal.

38. The method of claim 35 wherein the equalizing filter is a digital equalizing filter having a first stage to high pass filter with a low end cutoff of about 0.05 Hz and a second stage to boost low frequencies.

39. An implantable cardiac stimulation system comprising:

an implantable cardiac stimulation device to provide a heart activity signal of a heart;

an implantable electrode coupled to the implantable cardiac stimulating device, the implantable electrode to sense cardiac electrical activity and to provide an intracardiac electrogram signal; and

a filter to filter the intracardiac electrogram signal with a low frequency cutoff of no greater than about 0.4 Hz and a high frequency cutoff of no less than about 20 Hz to provide a filtered intracardiac electrogram signal, the filtered intracardiac electrogram signal resembling a surface electrocardiogram; and

an external display device to display the filtered intracardiac electrogram signal.

40. An implantable cardiac stimulation system comprising:

an implantable cardiac stimulation device to provide a heart activity signal of a heart;

an implantable electrode coupled to the implantable cardiac stimulating device, the implantable electrode to sense cardiac electrical activity and to provide an intracardiac electrogram signal;

a first filter to filter the intracardiac electrogram signal with a low frequency cutoff of no greater than about 1 to 2 Hz and a high frequency cutoff of no less than about 250 Hz to provide a filtered intracardiac electrogram signal, and

an external display device having a second filter to further filter the filtered intracardiac electrogram signal, the further filtered intracardiac electrogram resembling a surface electrocardiogram, and the external display device to display the further filtered intracardiac electrogram signal.

41. The system of claim 40 wherein the second filter is a digital equalizing filter.

42. The system of claim 41 wherein the digital equalizing filter has a and a second stage.

43. The system of claim 42 wherein the first stage is a high pass filter end cutoff of about 0.05 Hz and the second stage boosts low frequencies.