Method and system for temperature analysis to provide an early marker of congestive heart failure progress that precedes a patient's symptoms

• US 8,855,761 B2
• Filed: 07/10/2009
• Issued: 10/07/2014
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Texas Heart Institute
• Original Assignee: Texas Heart Institute
• Inventors: Wilson, James W., Ferguson, James J., Cox, Casey D.
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): GHAND, JENNIFER LEIGH-STEWAR
• Application Number:
  US12/500,990
• Publication Number:
  US 20100010552A1
• Time in Patent Office: 1,915 Days
• Field of Search: 607/6, 607/21
• US Class Current: 607/6
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61N 1/3655 controlled by body or blood temperature
• CPC Class Codes: G16H 40/63 for local operation

Abstract

The temperature of a patient is a significant predictor of death in heart failure patients. Temperature provides a window into the physiology of the patient'"'"'s underlying condition and may be used as an early marker for CHF exacerbations. The patient'"'"'s temperature is taken to form a time series of temperature values. In accordance with some embodiments, the time series of temperature values is converted to the frequency domain by, for example, a discrete Fourier Transform. The frequency domain representation then is analyzed for a marker indicative of the worsening condition of the patient. In accordance with other embodiments, the patient'"'"'s time series of temperature values is analyzed for a marker using, for example, Cosinor analysis. In yet other embodiments, both the time and frequency domain temperature data is analyzed for markers of the patient'"'"'s worsening medical condition.

Claims

1. A method of predicting worsening of heart failure in a patient, comprising:

obtaining, by a processor, time domain temperature data (TDTD) of core body temperature of the patient taken over a time period of more than one day;

converting, by said processor, said TDTD to a frequency domain representation (FDR);

determining, by said processor, a first marker indicative of worsening of heart failure of the patient by analyzing the FDR;

determining, by said processor, a second marker indicative of worsening of heart failure by analyzing the TDTD, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding;

weighing outputs of at least two analysis techniques to render a total score indicative of the current condition of the patient, wherein the at least two analysis techniques comprise a technique for analyzing the TDTD and another technique for analyzing the FDR; and

determining that the patient is experiencing worsening heart failure based on the total score.

2. The method of claim 1 wherein said TDTD is selected from the group consisting of temperature taken by a Foley™

urinary catheter, temperature taken by a rectal probe, rectal cavity temperature, bladder temperature, esophagus temperature, trachea temperature.

3. The method of claim 1 wherein obtaining the TDTD comprises acquiring temperature values from at least one temperature sensor or reading temperature values from storage.

4. The method of claim 1 wherein converting said TDTD to FDR comprises performing at least one of Fourier transform, wavelet transform, and Chirplet transform.

5. A system comprising a processor that receives time domain temperature data (TDTD) pertaining to a patient, converts said TDTD to a frequency domain representation (FDR), and determines a first marker indicative of worsening of heart failure of the patient by analyzing the FDR and determines a second marker indicative of worsening of heart failure by analyzing the TDTD, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding, wherein the processor weighs outputs of at least two analysis techniques to render a total score indicative of the current condition of the patient, wherein the at least two analysis techniques comprise a technique for analyzing the TDTD and another technique for analyzing the FDR.

6. The system of claim 5 wherein said processor utilizes at least one of Fourier transform, wavelet transform, and Chirplet transform to convert said TDTD to FDR.

7. The system of claim 5 wherein the first marker indicative of worsening of heart failure is determined upon detecting oscillation in the amplitude of the peak at the patient'"'"'s circadian frequency in the FDR.

8. The system of claim 5 wherein the first marker indicative of worsening of heart failure is determined upon detecting an increase in the harmonics of the FDR at frequencies lower than the patient'"'"'s circadian frequency.

9. The system of claim 5 wherein the second marker indicative of worsening of heart failure is determined upon detecting a change in at least one of the mesor, amplitude, and acrophase of the Cosinor analysis of the TDTD.

10. The system of claim 5 wherein said processor reports at least one of the TDTD, the FDR, analysis outputs, and the total score to the patient or a healthcare provider, or both.

11. The system of claim 5 further comprising an alarm unit that generates an alarm upon the processor determining that at least one of the markers indicative of worsening of heart failure of the patient has exceeded a threshold.

12. The system of claim 5 further comprising a therapy delivery unit (TDU) that delivers therapy to the patient upon the processor determining that at least one of the markers indicative of worsening of heart failure of the patient has exceeded a threshold.

13. The system of claim 12, wherein the TDU comprises an implantable medical device.

14. The system of claim 12, wherein the TDU comprises an implantable pacemaker or defibrillator, comprising a pulse generator which is configured to generate an electrical stimulation signal upon determining that at least one of the markers has exceeded a threshold.

15. The system of claim 12, wherein the TDU comprises an implantable drug reservoir and a pump which is connected to the drug reservoir and configured to be activated upon determining that at least one of the markers has exceeded a threshold to deliver a drug in the reservoir to the patient.

16. The system of claim 5 further comprising a temperature sensor.

17. The system of claim 5 wherein the system is implantable.

18. The system of claim 5 further comprising an alarm unit that generates an alarm upon the processor determining that both the first and second markers indicative of worsening of heart failure of the patient have exceeded a threshold.

19. A non-transitory computer-readable storage medium (CRSM) containing software that, when executed by a processor, causes the processor to:

receive time domain temperature data (TDTD) of core body temperature of a patient taken over a time period of more than one day;

convert said TDTD to a frequency domain representation (FDR);

determine a first marker indicative of worsening of heart failure of the patient by analyzing the FDR;

determine a second marker indicative of worsening of heart failure by analyzing the TDTD, wherein analyzing the TDTD comprises performing at least one of Cosinor analysis, approximate entropy, tempogram, day-night mean temperature difference, body temperature daily range, interdaily stability, and time-lag embedding; and

weigh outputs of at least two analysis techniques to render a total score indicative of the current condition of the patient, wherein the at least two analysis techniques comprises a technique for analyzing the TDTD and another technique for analyzing the FDR.

20. The non-transitory CRSM of claim 19 wherein said software further causes the processor to report at least one of the TDTD, the FDR, analysis outputs, and the total score to the patient or a healthcare provider, or both.

21. The non-transitory CRSM of claim 19 wherein said software further causes the processor to activate an alarm unit connected to said processor to generate an alarm upon determining that at least one of the markers is indicative of worsening of heart failure of the patient.

22. An implantable medical device comprising

a pacemaker or a defibrillator including an electrical pulse generator;

and

a processor that receives time domain temperature data (TDTD) of core body temperature of a patient taken over a time period of more than one day, performs Cosinor analysis on said TDTD, converts said TDTD to a frequency domain representation (FDR), determines a first marker indicative of worsening of heart failure of the patient upon detecting a change in at least one of the mesor, amplitude, and acrophase of the Cosinor analysis of the TDTD, and determines a second marker indicative of worsening of heart failure by analyzing the FDR;

wherein said electrical pulse generator is configured to generate an electrical stimulation signal upon determination that at least one of the markers has exceeded a threshold; and

wherein the processor computes a score based on both the TDTD and the FDR.

23. The device of claim 22 further comprising an alarm unit that generates an alarm upon determining that at least one of the markers indicative of worsening of heart failure of the patient has exceeded a threshold.