System and method for monitoring myocardial performance using sensed ventricular pressures

• US 20060167514A1
• Filed: 01/27/2005
• Published: 07/27/2006
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: Barbro M. Kjellstrom, Edward Chinchoy, Kathryn E. Hilpisch
• Original Assignee: Barbro M. Kjellstrom, Edward Chinchoy, Kathryn E. Hilpisch
• Inventors: Chinchoy, Edward, Kjellstrom, Barbro M., Hilpisch, Kathryn E.
• Granted Patent: US 7,192,399 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36564 controlled by blood pressure

Abstract

A medical device chronically monitors cardiac function in a patient. An input circuit of the medical device receives a pressure signal representative of a pressure sensed within a ventricle of the patient'"'"'s heart as a function of time. A processor derives from the pressure signal a myocardial performance index based upon pressures in the ventricle. The processor then provides an output based upon the myocardial performance index.

Claims

1. A medical device for chronically monitoring cardiac function in a patient, comprising:

an input circuit that receives a pressure signal representative of a pressure sensed within a ventricle of a heart as a function of time; and

a processor that derives from the pressure signal a myocardial performance index based upon pressures in the ventricle and provides an output based upon the myocardial performance index.

2. A medical device according to claim 1 and further comprising a blood pressure sensor located in the ventricle for providing the pressure signal to the input circuit.

3. A medical device according to claim 2 wherein the blood pressure sensor is located in the right ventricle.

4. A medical device according to claim 1 wherein the input circuit also receives an electrical signal representative of electrical activity in the heart as a function of time.

5. A medical device according to claim 4 wherein the processor determines the myocardial performance index as a function of a pre-ejection interval and a systolic time interval, the intervals being derived from the pressure and electrical signals.

6. A medical device according to claim 5 wherein the input circuit also receives a heart rate signal representative of a heart rate of the patient as a function of time, and wherein the processor further determines a heart-rate normalized myocardial performance index as a function of the myocardial performance index and the heart rate.

7. A medical device according to claim 4 wherein the processor determines the myocardial performance index as a function of a pre-ejection interval, a post-ejection interval, and a systolic time interval, the intervals each being derived from the pressure and electrical signals.

8. A medical device according to claim 1 and further comprising a memory for storage of a myocardial performance index threshold determined for the patient, wherein the processor detects when the myocardial performance index is greater than the myocardial performance index threshold.

9. A medical device according to claim 8 wherein the output provided by the processor is a warning signal indicating that the myocardial performance index has risen above the myocardial performance index threshold.

10. A medical device according to claim 1 wherein the output provided by the processor is a therapy control signal based upon the myocardial performance index, the control signal being provided to adjust a therapy of the patient.

11. A medical device according to claim 1 wherein the output is a waveform representative of the myocardial performance index as a function of time.

12. A method for chronically monitoring cardiac function in a patient, the method comprising:

sensing a blood pressure within a ventricle of the patient'"'"'s heart as a function of time;

deriving from the sensed blood pressure a myocardial performance index based upon pressure in the ventricle; and

providing an output based upon the myocardial performance index.

13. A method according to claim 12 wherein the blood pressure is sensed by a blood pressure sensor adapted to be located in the ventricle.

14. A method according to claim 13 wherein the ventricle comprises the right ventricle.

15. A method according to claim 12 and further comprising:

obtaining an electrical signal representative of the electrical activity in the heart as a function of time.

16. A method according to claim 15 wherein deriving a myocardial performance index comprises:

determining from the pressure signal and the electrical signal a pre-ejection interval and a systolic time interval; and

determining the myocardial performance index as a function of the pre-ejection interval and the systolic time interval.

17. A method according to claim 16 and further comprising:

obtaining a heart rate signal representative of a heart rate of the patient; and

determining a heart-rate normalized myocardial performance index as a function of the myocardial performance index and the heart rate.

18. A method according to claim 15 wherein deriving a myocardial performance index further comprises:

determining from the pressure signal and the electrical signal a pre-ejection interval, a post-ejection interval, and a systolic time interval; and

determining the myocardial performance index as a function of the pre-ejection interval, the post-ejection interval, and the systolic time interval.

19. A method according to claim 12 and further comprising:

determining a myocardial performance index threshold for the patient; and

detecting when the myocardial performance index is greater than the myocardial performance index threshold.

20. A method according to claim 19 wherein providing an output based upon the myocardial performance index comprises:

providing a warning signal upon the detection of the myocardial performance index rising above the myocardial performance index threshold.

21. A method according to claim 12 wherein providing an output based upon the myocardial performance index comprises:

providing a therapy control signal based upon the myocardial performance index to adjust a therapy of the patient.

22. A method according to claim 12 wherein providing an output based upon the myocardial performance index comprises:

outputting a waveform representative of the myocardial performance index as a function of time.

23. A method for determining a set of pacing settings for a pacemaker implanted in a patient, the method comprising:

administering a plurality of pacing settings, each pacing setting being administered for a period of time;

monitoring an effect of each pacing setting on a myocardial performance index, the myocardial performance index being determined from a pressure signal sensed from within a ventricle of the patient'"'"'s heart; and

selecting from the plurality of pacing settings a set of pacing settings based upon the myocardial performance index.