Detection of function of implanted medical devices

• US 7,904,160 B2
• Filed: 11/01/2007
• Issued: 03/08/2011
• Est. Priority Date: 10/15/2003
• Status: Active Grant

• Current Assignee: GE Medical Systems Information Technologies Incorporated (General Electric Company)
• Original Assignee: GE Medical Systems Information Technologies Incorporated (General Electric Company)
• Inventors: Young, Brian J., Albert, David E., Gray, James M., Hernke, David G., Schluter, Paul S., Wolfe, Robert T., Brodnick, Donald E.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US11/933,868
• Publication Number:
  US 20080051844A1
• Time in Patent Office: 1,223 Days
• Field of Search: 607/2, 607/5, 607/9, 607 27- 31, 607/601, 128/901
• US Class Current: 607/27
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

A monitoring system and method for monitoring signals from an implantable medical device are disclosed. The monitoring system and method include a monitor configured to detect a radio frequency artifact from the signals of the implantable medical device and circuitry for processing the radio frequency artifact from the signals of the implantable medical device.

Claims

1. A method for monitoring a signal from an implantable medical device comprising:

receiving a plurality of voltage samples, each of the plurality of voltage samples from one of a plurality of channels of the signal;

filtering each of the voltage samples;

detecting at least one of a leading edge and a trailing edge for a pulse for each of the voltage samples;

measuring width of a pulse for each of the voltage samples;

measuring amplitude of the pulse for each of the voltage samples;

validating the pulse, when at least one of the plurality of voltage samples has a valid amplitude;

classifying the pulse; and

storing information about the pulse.

2. The method of claim 1 further comprising processing the signal to determine where pacing stimulus artifact occurs in an ECG and identify heart beats that are paced and heart beats that are not paced and occurrences of pacing that fail to stimulate a heart beat.

3. The method of claim 2 wherein the voltage samples are filtered to accentuate pacing stimulus artifact.

4. The method of claim 3 wherein the pulse is validated and classified by comparing the pulse to one or more pulses stored in a database.

5. The method of claim 2 wherein the voltage samples are filtered with high pass filter to preserve sharp edges to accurately measure pulse width and amplitude.

6. The method of claim 1 wherein at least one of the leading edge and the trailing edge is detected when the absolute value of the difference between two consecutive samples exceeds a threshold.

7. The method of claim 6 wherein at least one of the leading edge and the trailing edge is detected when output of a high pass filter exceeds a threshold.

8. The method of claim 6 wherein at least one of the leading edge and the trailing edge is detected when the time between two non-consecutive samples exceeds a maximum expected artifact rise time.

9. The method of claim 1 wherein the width is measured by determining the difference in time between the leading edge and the trailing edge.

10. The method of claim 9 wherein the amplitude is measured by finding a sample having the most extreme value compared to zero between the leading edge and trailing edge.

11. A system for monitoring a signal from an implantable medical device comprising:

means for receiving a plurality of voltage samples, each of the plurality of voltage samples from one of a plurality of channels of the signal;

means for filtering each of the voltage samples;

means for detecting a leading and trailing edge for a pulse for each of the voltage samples;

means for measuring width of a pulse for each of the voltage samples;

means for validating the pulse, when at least one of the plurality of voltage samples has a valid amplitude;

means for classifying the pulse; and

means for storing information about the pulse.

12. The system of claim 11 further comprising a means for processing the signal to determine where pacing stimulus artifact occurs in an ECG and identify heart beats that are paced and heart beats that are not paced and occurrences of pacing that fails to stimulate a heart beat.

13. The system of claim 12 wherein the voltage samples are filtered to accentuate pacing stimulus artifact.

14. The system of claim 13 wherein at least one of the leading edge and the trailing edge is detected when output of a high pass filter exceeds a threshold.

15. The system of claim 14 wherein the amplitude is measured by finding a sample having the most extreme value compared to zero between the leading edge and trailing edge.

16. The system of claim 13 wherein at least one of the leading edge and the trailing edge is detected when the time between two non-consecutive samples exceeds a maximum expected artifact rise time.

17. The system of claim 12 wherein the voltage samples are filtered with high pass filter to preserve sharp edges to accurately measure pulse width and amplitude.

18. The system of claim 11 wherein at least one of the leading edge and the trailing edge is detected when the absolute value of the difference between two consecutive samples exceeds a threshold.

19. The system of claim 11 wherein the width is measured by determining the difference in time between the leading edge and the trailing edge.

20. The system of claim 11 wherein the pulse is validated and classified by comparing the pulse to one or more pulses stored in a database.

21. A method for monitoring a signal from an implantable medical device comprising:

receiving a plurality of voltage samples, each of the plurality of voltage samples from one of a plurality of channels of the signal;

filtering each of the voltage samples;

processing the signal to determine where pacing stimulus artifact occurs in an ECG and identify heart beats that are paced and heart beats that are not paced and occurrences of pacing that fail to stimulate a heart beat for each of the voltage samples;

detecting at least one of a leading edge and a trailing edge for a pulse, wherein at least one of the leading edge and the trialing edge is detected when the absolute value of the difference between two consecutive samples exceeds a threshold for each of the voltage samples;

measuring width of a pulse wherein the width is measured by determining the difference in time between the leading edge and the trailing edge for each of the voltage samples;

measuring amplitude of the pulse wherein the amplitude is measured by finding a sample having the most extreme value compared to zero between the leading edge and trailing edge for each of the voltage samples;

validating the pulse, when at least one of the plurality of voltage samples has a valid amplitude;

classifying the pulse; and

storing information about the pulse.