METHOD AND DEVICE FOR USING IMPEDANCE MEASUREMENTS BASED ON ELECTRICAL ENERGY OF THE HEART

• US 20110087119A1
• Filed: 08/16/2010
• Published: 04/14/2011
• Est. Priority Date: 10/01/2001
• Status: Active Application

• Current Assignee: Eckhard Alt, Maik Gollasch
• Original Assignee: Eckhard Alt, Maik Gollasch
• Inventors: Alt, Eckhard, Gollasch, Maik
• Granted Patent: US 8,219,198 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• 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 1/36521 the parameter being derived from measurement of an electrical impedance

Abstract

A method and a device are disclosed for evaluating the cardio-circulatory and pulmonary condition of a patient, including determining the patient'"'"'s thoracic impedance based on information solely derived from the electrical energy generated by the patient'"'"'s own heart.

Claims

1. A method of evaluating the cardio-circulatory and ventilatory condition of a patient, which comprises the step of determining the patient'"'"'s thoracic impedance based on information solely derived from the electrical energy generated by the patient'"'"'s own heart.

14. The method of claim 1, including using the patient'"'"'s thoracic impedance information to optimize the function of a rate adaptive pacemaker.

15. The method of claim 1, including using the patient'"'"'s thoracic impedance information to optimize monitoring of the patient'"'"'s congestive heart failure.

2. A method of adjusting the heart rate of a patient by means of an implantable rate adaptive pacemaker, said method comprising the step of adjusting the pacing rate of said pacemaker in response to a determination of the patient'"'"'s intrinsic impedance derived solely from the electrical energy generated by the patient'"'"'s heart.

3. The method of claim 2, including a step of closed loop optimization of said rate adaptive pacemaker to achieve said adjustment of pacing rate.

16. The method of claim 2, including using the patient'"'"'s intrinsic impedance information to adapt the heart rate of a rate adaptive pacemaker accordingly.

17. The method of claim 2, including using the patient'"'"'s intrinsic impedance information instantaneously to influence the rate adaptation on an ongoing basis within minutes.

18. The method of claim 2, including using the patient'"'"'s intrinsic impedance information in which long term rate and cardio-circulatory response determine the rate adaptation on a long term daily or monthly basis.

4. A method of monitoring the cardiocirculatory status of a patient with an implantable device, said method comprising the step of calculating the patient'"'"'s impedance based on information derived from the electrical energy generated by the patient'"'"'s own heart.

5. The method of claim 4, wherein said implantable device is implanted subcutaneously.

6. The method of claim 4, wherein said device is adapted to monitor the patient'"'"'s EKG, and including the step of deriving changes in said impedance based on differential signal processing of said EKG.

7. The method of claim 6, including the step of applying information concerning said impedance changes within said device to determine the cardiocirculatory status of the patient.

8. The method of claim 4, wherein the patient is suffering from heart failure, and said device is adapted to monitor the patient'"'"'s heart failure by performing said calculation of impedance and processing thereof solely using said electrical energy generated by the patient'"'"'s own heart.

9. The method of enhancing the function of a body-implantable defibrillator, which comprises the steps of determining the impedance between sensing electrodes of said defibrillator, and changes in said impedance, based on energy generated by the heart of the patient in whom said defibrillator is implanted.

10. A device for evaluating the cardio-circulatory condition of a patient, said device comprising means for determining the patient'"'"'s thoracic impedance based on information solely derived from the electrical energy generated by the patient'"'"'s own heart.

11. The method of obtaining information about the cardiac function of a patient, said method comprising continuously processing electrical signal information from an EKG during depolarization and repolarization of the patient'"'"'s heart representing systole and diastole as different phases of the heart represented by said EKG, using electrical energy generated by the patient'"'"'s own heart.

12. The method of claim 11, including analyzing the impedance of the patient'"'"'s heart and its changes with systole from a point close to the T-Wave of the EKG signal, and deriving information on the diastolic status of the heart derived from an impedance signal close to the R-Wave of the EKG signal.

13. The method of claim 12, including using a comparison between systole and diastole to assess the cardio-circulatory status of the patient.

19. An implantable device for monitoring the cardio-pulmonary status of a patient, comprising means for determining the patient'"'"'s thoracic impedance from EKG signal information acquired by the device using electrical energy generated by the patient'"'"'s own heart.

20. The device of claim 19, wherein said device is adapted for subcutaneous implantation.

21. The device of claim 20, including surface mounted electrodes on said device to monitor the patient'"'"'s EKG.

22. The device of claim 19, including signal processing means for deriving information concerning changes in said impedance to determine the cardio-pulmonary status of the patient.

23. The device of claim 19, wherein said device is adapted for cardiac pacing, and includes means for negative feedback closed loop control of said cardiac pacing for optimization of pacing rate to match the fitness of the patient engaged in physical activity.