Method for recognizing rejection of transplanted hearts

• US 4,905,707 A
• Filed: 12/08/1986
• Issued: 03/06/1990
• Est. Priority Date: 11/20/1986
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Lekholm, Bengt A., Davies, David W.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/939,343
• Time in Patent Office: 1,184 Days
• Field of Search: 128/702-705
• US Class Current: 600/515
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

A method is disclosed for monitoring the body reaction against a heart transplant. When a heart is newly transplanted, electrocardiac signals from the transplanted heart are detected. The analog signals are converted to digital signals. A first differentiation of the digital signals is carried out over a continuous time period to create reference differentiated signals. At a later time during monitoring of the transplanted heart, analog electrocardiac signals are again detected from the transplanted heart. These analog signals are converted to digital signals. A first differentiation is carried out of these digital signals over a continuous time period to create monitored differentiated signals. The reference differentiated signals and the monitored differentiated signals are compared at least with respect to amplitude to create comparison results. All of the above operations occur within the body. These comparison results are recorded and stored for use in determining body rejection of the transplanted heart.

Claims

1. A method of monitoring a body reaction against a heart transplanted therein, comprising steps of:

detecting inside the body analog electrocardiac signals from a newly transplanted heart in the body;

within the body converting the analog signals to digital signals;

within the body carrying out a first differentiation of the digital signals over a continuous time period to create reference differentiated signals;

at a later time during monitoring of the heart, again detecting within the body analog electrocardiac signals from the transplanted heart;

within the body converting the analog signals to digital signals;

within the body carrying out a first differentiation of the digital signals over a continuous time period to create newly monitored differentiated signals;

within the body comparing the newly monitored differentiated signals with the reference differentiated signals to create comparison results;

recording and storing within the body the comparison results; and

at a desired time, transmitting the stored comparison results from inside the body to outside the body for use in analyzing body rejection of the transplanted heart.

2. A method according to claim 1 wherein amplitudes of the reference and newly monitored differentiated signals are compared.

3. A method according to claim 1 wherein intervals of the reference and newly monitored differentiated signals are also compared.

4. A method according to claim 1 wherein polarities of the reference and newly monitored differentiated signals are compared.

5. A method according to claim 1 wherein an amplitude sequence of said reference and newly monitored differentiated signals are also compared.

6. A method according to claim 1 including an additional step of supplying said compared results on demand by telemetry from internally to externally of the body.

7. A method according to claim 6 including the step of altering a patient to an unfavorable assessment of the comparison results.

8. A method according to claim 7 wherein the unfavorable assessment of the comparison results is indicated in an audible manner to the patient having said transplanted heart.

9. A method according to claim 1 wherein only analog electrocardiac signals with a frequency signal range of 0.016 Hz to 1 KHz are supplied for conversion to the digital signals.

10. A method according to claim 1 wherein said analog to digital conversion occurs at a frequency of 1024 Hz.

11. A method according to claim 1 wherein the newly monitored differentiated signals and corresponding comparison results are periodically created.

12. A method of monitoring a body reaction against a heart transplanted therein, comprising steps of:

detecting inside the body analog electrocardiac signals from a newly transplanted heart in the body;

within the body converting the analog signals to digital signals;

within the body carrying out a first differentiation of the digital signals over a continuous time period to create reference differentiated signals;

at a later time during monitoring of the heart, again detecting within the body analog electrocardiac signals from the transplanted heart;

within the body converting the analog signals to digital signals;

within the body carrying out a first differentiation of the digital signals over a continuous time period to create newly monitored differentiated signals;

within the body comparing at least with respect to amplitude the newly monitored differentiated signals with the reference differentiated signals to create comparison results;

recording and storing within the body the comparison results; and

using the stored comparison results for analyzing body rejection of the transplanted heart.