METHOD AND APPARATUS FOR TRENDING A PHYSIOLOGICAL CARDIAC PARAMETER

• US 20110009767A1
• Filed: 09/21/2010
• Published: 01/13/2011
• Est. Priority Date: 06/25/2003
• Status: Active Grant

• Current Assignee: Paul Goode
• Original Assignee: Paul Goode
• Inventors: Goode, Paul
• Granted Patent: US 8,340,747 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system

Abstract

The present invention relates to an implantable cardioverter-defibrillator or pacemaker whose standard circuitry is used to trend a physiological cardiac parameter using intra-cardiac impedance measurements. The trend information may be used to predict the onset of a sudden cardiac death (SCD) event. By being able to predict the onset of an SCD event, patients and their physicians may be forewarned of a life-threatening event allowing them to respond accordingly. The trend information may also be used to predict the efficacy of cardiac-related medications, monitor progress of congestive heart failure, detect the occurrence of myocardial infarction, or simply track changes in sympathetic tone.

Claims

1. A system for monitoring congestive heart failure, the system comprising:

a measuring device configured to measure intra-cardiac impedance;

a derivation module configured to derive a physiologic cardiac parameter from the measured impedance;

a trending module configured to trend the derived parameter over spaced time intervals to create trended parameter data; and

an analyzing module configured to analyze the trended parameter data and monitor congestive heart failure status from the analysis.

2. The system of claim 1, wherein the analyzing module is configured to:

compare the trended parameter data; and

detect a difference between the trended parameter data.

3. The system of claim 1, comprising a reporting module configured to report the trended parameter data to an outside source.

4. The system of claim 1, wherein the derived parameter includes at least one of stroke volume, ejection fraction, and pre-ejection period.

5. The system of claim 1, wherein the derivation module and the trending module are packaged with an implantable device.

6. The system of claim 1, comprising an external device configured to store the trended parameter data.

7. The system of claim 1, comprising a separately located device, wherein the system is configured to download the trended parameter data to the separately located device.

8. The system of claim 7, wherein the separately located device includes an external patient management system.

9. The system of claim 1, wherein the measuring device is configured to measure intra-cardiac impedance using an implantable cardiac rhythm management device.

10. The system of claim 1, wherein the measuring device is coupled to least two electrodes configured to measure a voltage resulting from a current applied between the at least two electrodes, wherein the voltage is used to determine the intra-cardiac impedance.

11. A device for trending a physiologic cardiac parameter, the device comprising:

an impedance module configured to measure an intra-cardiac impedance at spaced time intervals;

a derivation module configured to derive the physiologic cardiac parameter using the measured impedance;

a trending module configured to generate trended parameter data using the derived physiologic cardiac parameter; and

an analyzing module configured to analyze the trended parameter data and monitor congestive heart failure status from the analysis.

12. The device of claim 11, comprising a reporting module configured to report the trended parameter data to an outside source.

13. The device of claim 11, wherein the derived physiologic cardiac parameter includes at least one of stroke volume, ejection fraction, and pre-ejection period.

14. The device of claim 11, wherein the impedance module is in communication with at least two electrodes, the at least two electrodes being configured to measure a voltage resulting from a current applied between the at least two electrodes, wherein the voltage is used to determine the intra-cardiac impedance.

15. The device of claim 11, wherein the device is configured to download the trended parameter data to an external storage device.

16. A device-readable medium comprising instructions that, when performed by a previously-implanted medical device, cause the device to perform acts comprising:

measuring an intra-cardiac impedance at spaced time intervals;

deriving a physiologic cardiac parameter using the measured impedance;

generating trended parameter data using the derived physiologic cardiac parameter; and

analyzing the trended parameter data; and

monitoring congestive heart failure status from the analysis.

17. The device-readable medium of claim 16, wherein analyzing the trended parameter data includes:

comparing the trended parameter data; and

detecting a difference between the trended parameter data.

18. The device-readable medium of claim 16, comprising instructions that, when performed by the previously-implanted medical device, cause the device to perform acts comprising reporting the trended parameter data to an outside source.

19. The device-readable medium of claim 16, wherein deriving the physiologic cardiac parameter includes deriving at least one of stroke volume, ejection fraction, and pre-ejection period.

20. The device-readable medium of claim 16, comprising instructions that, when performed by the previously-implanted medical device, cause the device to perform acts comprising storing the trended parameter data on an external device.