Method and apparatus for detecting ischemia

• US 20050004476A1
• Filed: 05/28/2004
• Published: 01/06/2005
• Est. Priority Date: 05/28/2003
• Status: Abandoned Application

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Payvar, Saeed, Casscells, Samuel Ward III
• Application Number:
  US10/857,603
• Publication Number:
  US 20050004476A1
• Time in Patent Office: Days
• US Class Current: 600/481
• 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: A61N 1/3655 controlled by body or blood temperature

Abstract

The current invention includes methods to monitor and detect myocardial ischemia/infarction using apical regional temperature and/or coronary sinus blood temperature, and comparing those measurements to regional baselines as well as the core body temperature. Methods for combining such temperature measurements with a broad series of other indicators of myocardial ischemia/infarction are explained. This invention also includes description of devices that put the above described method in use, as well as includes means to provide the patient and/or his health-care provider with easily accessible information leading to timely initiated therapy, and also means to communicate with other devices that provide such early treatment.

Claims

1. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart and taking a blood core temperature (T_C) elsewhere, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus and determining if T_CS increases relative to T_C.

2. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart after taking a baseline temperature (T-baseline) in the right atrium of the heart with said sensor, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus and determining if T_CS increases relative to T-baseline.

3. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart and a temperature sensor in the right atrium of a heart, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus and measuring temperature in the right atrium (T_RA) sensed by said sensor in the right atrium and determining if T_CS increases relative to TRA.

4. A method of detecting cardiac ischemia comprising attaching a temperature sensor in the wall of the apex of a heart, taking a blood core temperature (T_C) elsewhere, measuring temperature of the apex (T-apex) sensed by said sensor in said wall and determining if T-apex decreases relative to T_C.

5. A method of detecting cardiac ischemia comprising attaching a temperature sensor in the wall of the apex of a heart after taking a baseline temperature (T-baseline) in the right atrium of the heart with said sensor, measuring temperature of the apex (T-apex) sensed by said sensor in said wall and determining if T-apex decreases relative to T-baseline.

6. A method of detecting cardiac ischemia comprising attaching a temperature sensor in the wall of the apex of a heart and a temperature sensor in the right atrium of a heart, measuring temperature of the apex (T-apex) sensed by said sensor in said wall and measuring temperature in the right atrium (T_RA) sensed by said sensor in the right atrium and determining if T-apex decreases relative to T_RA.

7. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart, taking a blood core temperature (T_C) elsewhere, attaching a temperature sensor in the wall of the apex of a heart, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus, measuring temperature of the apex (T-apex) sensed by said sensor in said wall, and determining if the ratio of T_CS to T-apex increases.

8. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart after taking a baseline temperature (T-baseline) in the right atrium of the heart with said sensor, attaching a temperature sensor in the wall of the apex of a heart, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus, measuring temperature of the apex (T-apex) sensed by said sensor in said wall, and determining if and determining if the ratio of T_CS to T-apex increases.

9. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart and a temperature sensor in the right atrium of a heart, attaching a temperature sensor in the wall of the apex of a heart, measuring temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus, measuring temperature of the apex (T-apex) sensed by said sensor in said wall, and determining if the ratio of T_CS to T-apex increases.

10. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline and determining if the average of the waveforms increases.

11. The method of claim 10 further characterized by determining if the average increased waveform is characterized by a rapid slope of increase slowing to a plateau.

12. The method of claim 10 further characterized in that said average is the mean of the oscillation of the waveform.

13. The method of claim 10 further characterized in that said average is the size of the area of the curve under the waveform.

14. The method of claim 10 in which said core temperature baseline is taken by said sensor in the right atrium of the heart before placing the sensor in the coronary sinus.

15. The method of claim 10 further comprising placing a temperature sensor in the right atrium of the heart and measuring temperature in the right atrium (T_RA) sensed by said sensor in the right atrium to establish baseline core temperature.

16. The method of claim 10 further comprising determining the size and/or severity of a region of ischemia by determining the increase of average of the waveforms before cessation of an event of ischemia.

17. The method of claim 10 further comprising determining cessation of an event of ischemia by determining when the waveform average decreases after said increase, to values below pre-ischemic values.

18. The method of claim 10 further comprising determining cessation of an event of ischemia by determining that the slope of decrease of the average of the waveform is sharper than the slope of increase of the waveform.

19. A method of detecting cardiac ischemia involving tachycardia comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline and determining if the frequency of the waveforms increases.

20. The method of claim 19 further comprising determining the size and/or severity of a region of ischemia by determining an increase of frequency the waveforms before cessation of an event of ischemia.

21. The method of claim 19 comprising determining cessation of an event of ischemia by determining when the waveform frequency decreases after said increase to pre-ischemic values.

22. The method of claim 19 in which said core temperature baseline is taken by said sensor in the right atrium of the heart before placing the sensor in the coronary sinus.

23. The method of claim 19 further comprising placing a temperature sensor in the right atrium of the heart and measuring temperature in the right atrium (T_RA) sensed by said sensor in the right atrium to establish baseline core temperature.

24. A method of detecting cardiac ischemia comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline, and determining if the amplitude of the waveforms decreases.

25. The method of claim 24 further comprising determining the size and/or severity of a region of ischemia by determining the decrease of amplitude of the waveforms.

26. The method of claim 24 in which said core temperature baseline is taken by said sensor in the right atrium of the heart before placing the sensor in the coronary sinus.

27. The method of claim 24 further comprising placing a temperature sensor in the right atrium of the heart and measuring temperature in the right atrium (T_RA) sensed by said sensor in the right atrium to establish baseline core temperature.

28. A method of detecting rhythm abnormality of the heart comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline, and determining if the waveforms of temperature in the coronary sinus is atypical for waveforms of temperature in the normal heart.

29. A method of tracing pressure in coronary arteries comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline, and ascertaining the phase of said waveforms.

30. A method of determining blood flow in coronary arteries comprising placing a temperature sensor in the coronary sinus of a heart, measuring the waveforms of temperature in the coronary sinus (T_CS) sensed by said sensor in the coronary sinus relative to a core blood temperature baseline, and ascertaining the shape of said waveforms.

31. A method of monitoring a patient with coronary artery disease for occurrence of myocardial ischemia and/or infarction, which:

(a) measures patient'"'"'s core body temperature,

(b) measures patient'"'"'s right ventricular apex myocardial temperature,

(c) calculates their difference,

(c) uses the above said to indicate a change in the temperature gradient as criteria to indicate occurrence of ischemia and/or infarction.

(d) selectively alarms the patient or the health caregiver in a time that best suits patient'"'"'s condition.

32. The method of claim 31 that is further characterized by that to indicate ischemia and/or infarction, it analyzes the characteristics of the pattern of temperature change across the coronary sinus and the great cardiac vein at two or more locations.

34. The method of claim 31 or 32 that is further characterized in that to indicate ischemia and/or infarction, the above said criteria would be adjusted based on the desired sensitivity of the alarming algorithm.

35. The method of claim 31 or 32 that is further characterized in that to indicate ischemia, it uses the above said in addition to any one or more of the following internal and external factors that affect patient'"'"'s body temperature and the activity of the heart:

(a) patient'"'"'s level of activity

(b) use of medications, alcohol consumption, and smoking

36. The method of claim 31 in which said temperature change will be corrected for coronary sinus flow.

37. The method of claim 31 in which information regarding one or more of the following factors will be analyzed to indicate the occurrence of myocardial ischemia and/or infarction:

increased coronary sinus pressure, decreased coronary sinus pH, decreased coronary sinus pO2, increased coronary sinus pCO2, increased coronary sinus lactate, increased ratio of lactate to pyruvate in the coronary sinus, increased ratio of the reduced form of nicotine amide adenine dinucleotide (NADH) to nicotine amide adenine dinucleotide (NAD+) in the coronary sinus, increased ratio of the reduced form of nicotinamine-adenine dinucleotide phosphate (NADPH) to nicotinamine-adenine dinucleotide phosphate (NADPH) in the coronary sinus, increased ST segment, decreased ST segment, ventricular tachycardia, T wave changes, QRS changes, decreased patient activity, increased respiratory rate, decreased transthoracic impedance, decreased cardiac output, increased pulmonary artery diastolic pressure, increased myocardial creatinine kinase, increased troponin, and changed myocardial wall motion.

38. The method of claim 32 in which information regarding one or more of the following factors will be analyzed to indicate the occurrence of myocardial ischemia and/or infarction:

decreased local myocardial pressure, decreased myocardial pH, decreased myocardial pO2, increased myocardial pCO2, increased myocardial lactate, increased ratio of lactate to pyruvate in the myocardium, increased ratio of the reduced form of nicotine amide adenine dinucleotide (NADH) to nicotine amide adenine dinucleotide (NAD⁺) in the myocardium, increased ratio of the reduced form of nicotinamine-adenine dinucleotide phosphate (NADPH) to nicotinamine-adenine dinucleotide phosphate (NADPH) in the myocardium, increased ST segment, decreased ST segment, ventricular tachycardia, T wave changes, QRS changes, decreased patient activity, increased respiratory rate, decreased transthoracic impedance, decreased cardiac output, increased pulmonary artery diastolic pressure, increased myocardial creatinine kinase, increased troponin, and changed myocardial wall motion.

33. The method of claim 33 that is further characterized by that data from two or more locations across the coronary sinus and the great cardiac vein is used to indicate the specific region of the heart that suffers ischemia and/or infarction.

39. Apparatus and software for monitoring a patient with coronary artery disease and indicate occurrence of myocardial ischemia and/or infarction, comprising:

(a) rewritable data storage that keeps patients customized alarming criteria, and other information detailed below,

(b) two temperature detectors for sensing temperatures of a patient'"'"'s right atrium and coronary sinus and generating signals representative of the sensed temperatures,

(c) output device providing means for alarming the occurrence of myocardial ischemia and/or infarction,

(d) processing unit that;

(i) communicates with temperature sensors and rewritable data storage

(ii) runs the software that records temperature measurements, calculates the gradient and its change over time and analyses the pattern of temperature change based on the output of (b), stores these on a time stamped basis in (a), and uses such to detect occurrence of myocardial ischemia and/or infarction.

(iii) communicates with the output device (c) to alarm the patient or patient'"'"'s health caregiver.

40. The apparatus of claim 40 in which said detectors are located in the right atrium and right ventricular apex.