ELECTROMEDICAL IMPLANT AND MONITORING SYSTEM INCLUDING THE ELECTROMEDICAL IMPLANT

• US 20110224527A1
• Filed: 03/02/2011
• Published: 09/15/2011
• Est. Priority Date: 03/09/2010
• Status: Active Grant

• Current Assignee: Biotronik SE & Company KG
• Original Assignee: Biotronik SE & Company KG
• Inventors: Lippert, Michael, Czygan, Gerald, Skerl, Olaf
• Granted Patent: US 8,491,485 B2
• Time in Patent Office: Days
• US Class Current: 600/374
• 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 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• 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

Abstract

An electromedical implant (100, 101, 102, 103) for monitoring a cardiac blood flow (B1) of a patient includes a detector (10, 10′, 10″) which obtains a first measurement signal (S1) associated with the cardiac blood flow (B1) and a second measurement signal (S2) associated with the epithoracic, peripheral blood flow (B2). A monitoring assembly (20) then generates a first parameter (P1) from the first measurement signal (S1) which is indicative of a time (t_sys) at which blood is ejected from the heart, and a second parameter (2) from the second measurement signal (S2) which is indicative of a time (t_gef) of a blood pulse in the thoracic tissue which is associated with the ejection of blood. An evaluation unit (30) then generates a pulse transit time (Δt=t_gef−t_sys) from the first parameter (P1) and the second parameter (P2). The detector (10, 10′, 10″) includes an impedance measuring unit (12) having an electrode assembly (11, 11′) for detection of at least the second measurement signal (S2) in the form of an impedance signal.

Claims

1. An electromedical implant including:

a. a detector configured to obtain;

(1) a first measurement signal (S1) associated with a cardiac blood flow (B1) of a living being, and

(2) a second measurement signal (S2) associated with an epithoracic, peripheral blood flow (B2) of the living being, the second measurement signal (S2) being an impedance signal;

b. a monitoring assembly in communication with the detector, the monitoring assembly being configured to obtain;

(1) a first parameter (P1) from the first measurement signal (S1) representative of a time (t_sys) at which blood is ejected from the heart, and

(2) a second parameter (P2) from the second measurement signal (S2) representative of a time (t_gef) of a blood pulse in the thoracic tissue which is associated with the ejection of blood;

c. an evaluation unit in communication with the monitoring assembly, the evaluation unit being configured to generate a pulse transit time (Δ

t) from the first parameter (P1) and the second parameter (P2).

2. The implant of claim 1 wherein the first measurement signal (S1) is an impedance signal (S).

3. The implant of claim 1 wherein the first measurement signal (S1) is an ECG (electrocardiogram) signal.

4. The implant of claim 1 wherein the detector includes:

a. an impedance measuring unit configured to determine impedance, and

b. an electrode assembly in communication with the impedance measuring unit

5. The implant of claim 4 wherein the electrode assembly includes several poles whereby several impedance signals (S) can be determined by the impedance measuring unit.

6. The implant of claim 4 wherein the impedance measuring unit includes:

a. an exciter module for delivering an electric current via the electrode assembly, and

b. a sampling module for receiving a voltage via the electrode assembly.

7. The implant of claim 1 wherein the detector includes an electrode assembly, the electrode assembly including at least one electrode defined on a housing container defined about the implant.

8. The implant of claim 1 wherein the detector includes an electrode assembly, the electrode assembly including at least one electrode extending about the entirety of the circumference of a housing container defined about the implant.

9. The implant of claim 1 wherein the first measurement signal (S1) and the second measurement signal (S2) are obtained at different frequencies.

10. The implant of claim 1 wherein the second measurement signal (S2) is obtained at a frequency lower than any frequency at which the first measurement signal (S1) is determined.

11. The implant of claim 1 wherein the detector unit is configured to obtain the first measurement signal (S1) and the second measurement signal (S2) at different times.

12. The implant of claim 1 wherein the detector unit is configured to obtain a background impedance measurement signal at a frequency higher than any frequency at which the first measurement signal (S1) and second measurement signal (S2) are obtained.

13. The implant of claim 1 wherein the first measurement signal (S1) and the second measurement signal (S2) are defined by a portions of a time-varying impedance measurement signal (S) on opposite sides of an amplitude threshold.

14. The implant of claim 1 wherein the detector includes one or more of:

a. an acoustic detector,

b. an optical detector,

c. a pressure and/or expansion detector, and

d. an acceleration detector.

15. The implant of claim 1 further including a communication module for the wireless transmission of one or more of:

a. the pulse transit time (Δ

t), and

b. an evaluation result generated from the pulse transit time (Δ

t) by the evaluation unit.

16. The implant of claim 15 further including:

a. a receiving unit remote from the implant, the receiving unit being configured to wirelessly receive one or more of;

(1) the pulse transit time (Δ

t), and

(2) the evaluation result generated from the pulse transit time (Δ

t) by the evaluation unit;

b. a memory configured to store one or more of the pulse transit time (Δ

t) and the evaluation result.

17. A method for determining the pulse transit time (Δ

t) within a living being, the method including the performance of the following steps within an implant situated within a living being;

a. detecting a first measurement signal (S1) associated with the cardiac blood flow (B1) of the living being;

b. detecting a second measurement signal (S2) associated with the epithoracic, peripheral blood flow (B2) of the living being, the second measurement signal (S2) being an impedance signal;

c. determining a first parameter (P1) from the first measurement signal (S1), wherein the first parameter (P1) is representative of a time (t_sys) at which blood is ejected from the heart;

d. determining a second parameter (P2) from the second measurement signal (S2), the second parameter (P2) being representative of a time (t_gef) of a blood pulse in the thoracic tissue which is associated with the ejection of blood;

e. determining a pulse transit time (Δ

t) from the first parameter (P1) and the second parameter (P2).

18. The method of claim 17 wherein the first measurement signal (S1) is one or more of:

a. an impedance signal (S), and

b. an ECG (electrocardiogram) signal.

19. The method of claim 17 wherein the first measurement signal (S1) and the second measurement signal (S2) are obtained at different frequencies.

20. The method of claim 17 wherein the second measurement signal (S2) is obtained at a frequency lower than any frequency at which the first measurement signal (S1) is determined.

21. The method of claim 17 wherein the first measurement signal (S1) and the second measurement signal (S2) are obtained at different times.

22. The method of claim 17 further including the steps of:

a. detecting a background impedance measurement signal at a frequency higher than any frequency at which the first measurement signal (S1) and second measurement signal (S2) are obtained, and

b. determining the pulse transit time (Δ

t) in dependence on the first measurement signal (S1), second measurement signal (S2), and the background impedance measurement signal.

23. The method of claim 17 further including the step of wirelessly transmitting one or more of:

a. the pulse transit time (Δ

t), and

b. the evaluation result generated from the pulse transit time (Δ

t) by the evaluation unit;

to a receiving unit situated remotely from the living body.