Medical device comprising an impedance measurement means to measure visceral fat

• US 8,761,871 B2
• Filed: 09/25/2006
• Issued: 06/24/2014
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: St. Jude Medical AB (Abbott Laboratories)
• Original Assignee: St. Jude Medical AB (Abbott Laboratories)
• Inventors: Blomqvist, Andreas
• Primary Examiner(s): Schaetzle, Kennedy
• Assistant Examiner(s): LEE, ERICA SHENGKAI
• Application Number:
  US12/442,744
• Publication Number:
  US 20100100146A1
• Time in Patent Office: 2,829 Days
• Field of Search: 607/17, 607/40, 600/547
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/37258 Alerting the patient

Abstract

A medical device having an impedance measurement circuit connected to at least two intracorporeal measurement electrodes arranged to measure the impedance of tissue inside the body of a patient. The impedance measurement circuit is adapted to apply a measurement current/voltage signal to the electrodes to measure and calculate the impedance of the measurement tissue, and to apply the calculated impedance value to a storage unit. The stored impedance values are used, by an analysis unit, to measure the amount of visceral fat of the tissue object inside the body of the patient.

Claims

1. A medical device comprising:

an impedance measurement circuit comprising at least three measurement electrodes, configured to interact in vivo with intracorporeal tissue of a patient said at least three measurement electrodes of said impedance measurement circuit being configurable into at least two different measurement electrode configurations;

said impedance measurement circuit being configured to apply a measurement signal, selected from the group consisting of a measurement current and a measurement voltage, to each of said at least two different electrode configurations and to measure and calculate an impedance of the tissue therefrom, impedance measurement circuit being configured to measure said impedance of said tissue using each of said at least two different measurement electrode configurations and to calculate said impedance values from respective impedance measurements obtained with said at least three measurement electrodes in said at least two different measurement electrode configurations, respectively;

a storage unit connected to said impedance measurement circuit in which a plurality of respective impedance values, respectively representing impedance measured over time by said impedance measurement circuit, are stored; and

an analyzing unit, having access to said storage unit configured to calculate an amount of visceral fat in said tissue by comparing the respective impedance measurements obtained with said at least two electrode configurations to each other, wherein said at least two different measurement electrode configurations include one configuration wherein the impedance is essentially not influenced by visceral fat of said tissue.

2. A medical device as claimed in claim 1 wherein said analyzing unit is configured to determine a long term variation of said impedance values stored in said storage unit to identify changes of the visceral fat of the tissue.

3. A medical device as claimed in claim 1 comprising a timer that operates said impedance measurement circuit to cause said impedance measurement circuit to measure said impedance automatically and at regular time intervals.

4. A medical device as claimed in claim 1 wherein said impedance measurement circuit is configured to calculate a DC impedance as said impedance of said tissue.

5. A medical device as claimed in claim 1 wherein said impedance measurement circuit is configured to measure AC impedance of said tissue as said impedance.

6. A medical device as claimed in claim 5 wherein said impedance measurement circuit is configured to apply two measurement signals respectively having different frequencies.

7. A medical device as claimed in claim 6 wherein said storage unit stores said impedance values each as formed by a complex impedance value having a phase angle, and wherein said analyzing unit is configured to analyze said complex impedance values and to calculate said amount of visceral fat in said tissue using said phase angles.

8. A medical device as claimed in claim 1 wherein said analyzing unit comprises a predicting unit configured to predict trends of said visceral fat based on historical impedance values stored in said storage unit.

9. A medical device as claimed in claim 8 comprising an intracorporeal unit containing said impedance measurement circuit and said storage unit, and an extracorporeal unit containing said analyzing unit and said predicting unit, and wherein each of said intracorporeal unit and said extracorporeal unit contains circuitry configured to establish a communication link allowing communication at least between said storage unit and said analyzing unit.

10. A medical device as claimed in claim 1 comprising a notifying unit configured to generate a humanly-perceptible notification if said analysis unit determines an increase in said visceral fat of said tissue.

11. A medical device as claimed in claim 10 comprising an intracorporeal unit containing said impedance measurement circuit and said storage unit, and an extracorporeal unit containing said analysis unit and said notifying unit, and wherein each of said intracorporeal unit and said extracorporeal unit contains circuitry to establish a communication link allowing communication at least between said storage unit and said analysis unit.

12. A medical device as claimed in claim 1 comprising an in vivo cardiac stimulator configured to apply electrical stimulation to the heart of the patient.

13. A medical device comprising:

an impedance measurement circuit comprising a plurality of measurement electrodes, configured to interact in vivo with intracorporeal tissue of a patient, said plurality of electrodes of said impedance measurement circuit being configurable into at least a first measurement electrode configuration that is influenced by visceral fat of said tissue and a second measurement electrode configuration that is not influenced by said visceral fat of said tissue;

said impedance measurement circuit being configured to apply a measurement signal to said electrodes in each of said first and second different measurement electrode configurations based on the applied measurement signal to the electrode in each of said first and second different measurement electrode configurations, and to measure and calculate a first impedance value with said electrodes in said first measurement electrode configuration and to measure and calculate a second impedance value with said electrodes in said second measurement electrode configuration;

a storage unit connected to said impedance measurement circuit in which at least said first and second impedance values are stored; and

an analyzing unit, having access to said storage unit, configured to calculate an amount of visceral fat in said tissue by comparing the first impedance value with the second impedance value to obtain a comparison result indicative of said amount of visceral fat in said tissue.