Implant transmitter

• US 20070043298A1
• Filed: 08/22/2005
• Published: 02/22/2007
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Scisense Inc. (Measurement Innovations Corp.)
• Original Assignee: Scisense Inc. (Measurement Innovations Corp.)
• Inventors: Wood, Kim, Maymandi-Nejad, Mohammad, Placko, Milan, Poetschke, Blair, Plouf, Peter
• Granted Patent: US 7,803,121 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61N 1/3655 controlled by body or blood temperature
• CPC Class Codes: A61N 1/36564 controlled by blood pressure

Abstract

A monitoring system is provided that enables the monitoring of a heart in a living organism by continuously measuring both pressure and volume in a chamber of the heart, preferably the left ventricle (LV). The pressure and volume measurements are acquired using a single sensing tip and are communicated to a transmitting device to be wirelessly transmitted to a receiving device, wherein they are used to monitor the heart. The system may also incorporate a temperature measurement that can be transmitted with the volume and pressure measurement to provide further data for monitoring. The system may also extract an electrocardiogram (ECG) signal from the volume measurement. This allows the monitoring of up to four signals that can be used to determine the beat by beat state of cardiac output and any changes caused by disease or therapy. In addition to a compact design, the system may also incorporate an energy saving timing scheme that reduces the power required per acquisition cycle and thus increases the operational lifetime of the transmitting device.

Claims

1. A method of monitoring a heart of a living organism comprising the steps of:

situating a sensing tip within a chamber of said heart, said sensing tip comprising a pressure sensing device and a volume sensing device;

obtaining a pressure measurement and a volume measurement in said chamber using said pressure sensing device and said volume sensing device respectively;

communicating said measurements to a transmitting device; and

wirelessly transmitting electrical representations of said measurements to a receiving device, said electrical representations being used to monitor said heart.

2. The method of claim 1 wherein said transmitting device is located external to said heart.

3. The method of claim 1 further comprising the step of analysing said electrical representations to generate data indicative of the health of said heart.

4. The method of claim 3 wherein said data is a computed index based on said electrical representations.

5. The method of claim 3 wherein said data is displayed by said receiving device.

6. The method of claim 1 wherein said sensing tip extends along substantially the entirety of the longitudinal axis of said chamber.

7. The method of claim 1 wherein said pressure sensing device comprises a piezoresistive deflection sensor arranged on said sensing tip, said pressure measurement being sensed through flexure of said sensor.

8. The method of claim 1 wherein said volume sensing device comprises a first set of electrodes for transmitting and receiving an electrical signal through said chamber, said first set of electrodes being arranged at opposite ends of said sensing tip and flanking said pressure sensing device;

and at least one set of inner electrodes for sensing said electrical signal transmitted and received by said first set of electrodes to obtain said volume measurement, said at least one set of inner electrodes flanking said pressure sensing device and being arranged between respective ones of said first set of electrodes and said pressure sensing device.

9. The method of claim 1 wherein said transmitting device is implanted into a portion of said living organism.

10. The method of claim 1 further comprising the step of transmitting said electrical representations to a computing device.

11. The method of claim 1 wherein said transmitting device operates by obtaining a supply of energy to enable continuous monitoring.

12. The method of claim 1 further comprising the steps of obtaining an internal temperature measurement using a temperature sensing device, communicating said temperature measurement to said transmitting device, and transmitting an electrical representation of said temperature measurement to said receiving device.

13. The method of claim 1 further comprising the step of obtaining an electrocardiogram measurement from said volume measurement by conditioning said volume measurement to separate a noise portion of said volume measurement comprising said electrocardiogram measurement from a conductance portion of said volume measurement, and extracting said electrocardiogram measurement from said noise portion.

14. (canceled)

15. A system for monitoring a heart of a living organism comprising:

a sensing tip situated within a chamber of said heart and extending therethrough, said sensing tip comprising a pressure sensing device and a volume sensing device, said pressure sensing device adapted to obtain a pressure measurement in said chamber, said volume sensing device adapted to obtain a volume measurement in said chamber, and said sensing tip adapted for communicating said measurements;

a transmitting device for receiving said measurements from said sensing tip, said transmitting device being adapted to wirelessly transmit electrical representations of said measurements; and

a receiving station for receiving said electrical representations, said electrical representations being used to monitor said heart.

16. The system of claim 15 wherein said transmitting device is external to said heart.

17. The system of claim 15 further comprising a processor in communication with said receiving station for analysing said electrical representations to generate data indicative of the health of said heart.

18. The system of claim 17 wherein said data is an index computed by said processor based on said electrical representations.

19. The system of claim 17 wherein said receiving station comprises a display for displaying said data.

20. The system of claim 15 wherein said sensing tip extends along substantially the entirety of the longitudinal axis of said chamber.

21. The system of claim 15 wherein said pressure sensing device comprises a piezoresistive deflection sensor arranged on said sensing tip, said pressure measurement being sensed through flexure of said sensor.

22. The system of claim 15 wherein said volume sensing device comprises a first set of electrodes for transmitting and receiving an electrical signal through said chamber, said first set of electrodes being arranged at opposite ends of said sensing tip and flanking said pressure sensing device;

and at least one set of inner electrodes for sensing said electrical signal transmitted and received by said first set of electrodes to obtain said volume measurement, said at least one set of inner electrodes flanking said pressure sensing device and being arranged between respective ones of said first set of electrodes and said pressure sensing device.

23. The system of claim 15 wherein said transmitting device is implanted into a portion of said living organism.

24. The system of claim 23 wherein said living organism is a human and said transmitting device is implanted in proximity of the clavicle.

25. The system of claim 15 wherein said system comprises an analog to digital converter, said electrical representations are analog, and said system is adapted to convert said electrical representations from analog to digital using said analog to digital converter.

26. The system of claim 15 further comprising a computing device for receiving said electrical representations from said receiving device.

27. The system of claim 15 wherein said transmitting device obtains a supply of energy to enable continuous monitoring.

28. The system of claim 15 further comprising a temperature sensing device for obtaining an internal temperature measurement, said system being adapted for communicating said temperature measurement to said transmitting device, and said transmitting device being adapted for transmitting an electrical representation of said temperature measurement to said receiving device.

29. The system of claim of claim 16 wherein said processor is adapted to obtain an electrocardiogram measurement from said volume measurement by conditioning said volume measurement to separate a noise portion of said conductance signal comprising said electrocardiogram measurement from a conductance portion of said conductance signal, and extracting said electrocardiogram measurement from said noise portion.

30. (canceled)

31. A method for obtaining an intracardiac electrocardiogram signal comprising the steps of:

measuring a conductance signal from a heart chamber in a living organism, said conductance signal indicative of the volume of said chamber;

conditioning said conductance signal to separate a noise portion of said conductance signal comprising said electrocardiogram signal from a conductance portion of said conductance signal; and

extracting said electrocardiogram signal from said noise portion.