Broadband acoustic sensor for an implantable medical device

• US 20070049977A1
• Filed: 08/26/2005
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Chavan, Abhi, Maile, Keith, Von Arx, Jeffrey
• Granted Patent: US 7,615,012 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 7/023 for introduction into the body, e.g. into the oesophagus oesophageal ECG probes A61B5/285
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: A61N 1/3754 Feedthroughs

Abstract

An implantable medical device (IMD) is adapted for detecting acoustic chest sounds. The IMD includes a pulse generator having a compartment, the compartment defining an isolated cavity bounded by a back wall. A diaphragm is disposed over and encloses the cavity. An acoustic sensor adapted to sense chest sounds and generate a signal is disposed between the diaphragm and the back wall. The IMD also includes a control circuit disposed within the pulse generator. The circuit is operatively coupled to the acoustic sensor and is adapted to receive the signal.

Claims

1. An implantable medical device (IMD) comprising:

a pulse generator having a compartment, the compartment defining an isolated cavity bounded by a back wall;

a compartment diaphragm disposed over and enclosing the cavity;

an acoustic sensor adapted to sense chest sounds and generate a signal, the sensor disposed between the diaphragm and the back wall; and

a control circuit disposed within the pulse generator, the circuit operatively coupled to the acoustic sensor and adapted to receive the signal.

2. The IMD of claim 1 wherein an acoustic range of the acoustic sensor is from about 100 to about 5,000 Hz.

3. The IMD of claim 2 further comprising an accelerometer operatively coupled to the control circuit.

4. The IMD of claim 2 wherein the acoustic sensor includes an amplifier for amplifying the signal detected by the acoustic sensor.

5. The IMD of claim 1 wherein the acoustic sensor is a piezoresistive sensor or a capacitive sensor.

6. The IMD of claim 1 wherein the acoustic sensor is a MEMS microphone, and further wherein the MEMS microphone is attached to the back wall.

7. The IMD of claim 1 wherein a sensor diaphragm of the acoustic sensor is made from a piezoelectric material.

8. The IMD of claim 7 wherein the piezoelectric material comprises a piezoceramic material.

9. The IMD of claim 7 wherein the sensor diaphragm is attached to the compartment diaphragm using an epoxy or medical adhesive.

10. The IMD of claim 7 wherein the sensor diaphragm is separated from the compartment diaphragm by a gel having an acoustic impedance generally matching a second acoustic impedance of a body location in which the IMD is implanted.

11. The IMD of claim 1 wherein the pulse generator includes a housing and a header.

12. The IMD of claim 11 wherein the compartment is disposed in the housing, such that the compartment diaphragm is generally flush with a housing outer wall.

13. The IMD of claim 11 wherein the compartment extends outwardly from a housing outer wall and further wherein the back wall is formed by the housing outer wall.

14. The IMD of claim 11 wherein the electrical connection between the acoustic sensor and the controller includes a hermetically sealed feedthrough.

15. The IMD of claim 11 wherein the compartment is disposed in the header.

16. An implantable medical device (IMD) comprising:

a pulse generator;

a sensor module defining a compartment having a compartment diaphragm, the sensor module being structurally separate from the pulse generator;

an acoustic sensor adapted to sense chest sounds and generate a signal, the acoustic sensor located in the compartment; and

a control circuit disposed within the pulse generator, the circuit operatively coupled to the acoustic sensor and adapted to receive the signal.

17. The IMD of claim 16 wherein the sensor module comprises a tab, wherein the tab includes a diaphragm and defines an isolated cavity located behind the diaphragm.

18. The IMD of claim 16 further comprising a cardiac pacing lead comprising:

a flexible, elongated lead body having a proximal end and a distal end; and

an electrode coupled to the lead body near the distal end;

wherein the sensor module is integrated into the lead body.

19. The IMD of claim 18 wherein the acoustic sensor is a cylindrical transducer.

20. The IMD of claim 16 wherein the acoustic sensor is a MEMS microphone.

21. The IMD of claim 16 further comprising an accelerometer operatively coupled to the control circuit.

22. A cardiac function management (CFM) system for effecting operation of a human heart, the system comprising:

a pulse generator having a compartment, the compartment defining an isolated cavity bounded by a back wall;

a compartment diaphragm disposed over and enclosing the cavity;

an acoustic sensor adapted to sense chest sounds and generate a first signal, the sensor disposed between the compartment diaphragm and the back wall;

a cardiac lead having an electrode and adapted to sense electrical activity of the heart; and

a control circuit disposed within the pulse generator, the circuit operatively coupled to the acoustic sensor and the cardiac lead.

23. The CFM system of claim 22 further including an accelerometer operatively coupled to the control circuit.

24. The CFM system of claim 22 further including an external device in wireless communication with the control circuit for receiving at least a portion of the first signal.

25. The CFM system of claim 22 further including a remote device in communication with the external device for delivering the first signal to a remote user.