IMPLANTABLE HEART SOUND SENSOR WITH NOISE CANCELLATION

• US 20090030334A1
• Filed: 07/23/2007
• Published: 01/29/2009
• Est. Priority Date: 07/23/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Cinbis, Can, Anderson, David A.
• Granted Patent: US 7,682,316 B2
• Time in Patent Office: Days
• US Class Current: 600/528
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61B 7/006 Detecting skeletal, cartilage or muscle noise A61B7/003 and A61B7/008 take precedence
• CPC Class Codes: A61B 7/008 Detecting noise of gastric tract, e.g. caused by voiding
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

An implantable medical device system senses a first signal using a first acoustical sensor adapted to be operatively positioned in a first internal body location for sensing heart sounds in a patient. The system includes a second acoustical sensor adapted to be operatively positioned in a second internal body location for sensing sounds in the patient and generate a second signal that is less responsive to the heart sounds than the first acoustical signal. An implantable medical device including a housing and a processor enclosed in the housing receives the first signal and the second signal and generates a corrected first signal by canceling non-cardiac signals in the first signal using the second signal.

Claims

1. An implantable medical device system, comprising:

a first acoustical sensor adapted to be operatively positioned in a first internal body location to have a first level of responsiveness for sensing heart sounds in a patient, and to generate a first signal responsive to the sensed heart sounds;

a second acoustical sensor adapted to be operatively positioned in a second internal body location to have a second level of responsiveness for sensing heart sounds in the patient less than the first level of responsiveness, and to generate a second signal responsive to the heart sounds; and

an implantable medical device comprising a housing and a processor enclosed in the housing, the processor configured to receive the first signal and the second signal and generate a corrected first signal by canceling non-cardiac signals in the first signal using the second signal.

2. The system of claim 1 wherein at least one of the first acoustical sensor and the second acoustical sensor are positioned along the housing.

3. The system of claim 2 wherein the housing comprises:

a first side adapted to be inwardly-facing and having an internal surface and an external surface, and

a second side adapted to be outwardly-facing and having an internal surface and an external surface,

wherein at least one of the first acoustical sensor and the second acoustical sensor are positioned on the external surface of one of the first side and the second side of the housing.

4. The system of claim 3 wherein the first acoustical sensor is positioned along one of the internal surface and the external surface of the first side.

5. The system of claim 4 wherein the second acoustical sensor is positioned along one of the internal surface and the external surface of the second side.

6. The system of claim 1 further comprising an elongated medical lead coupled to the implantable medical device,

wherein at least one of the first acoustical sensor and the second acoustical sensor is positioned along the medical lead.

7. The system of claim 6 wherein the elongated medical lead is adapted to be positioned in a subcutaneous location.

8. The system of claim 1 wherein the implantable medical device comprises a telemetry circuit, and at least one of the first acoustical sensor and the second acoustical sensor comprises a telemetry circuit configured for bidirectional communication with the implantable medical device telemetry circuit.

9. An implantable medical device system, comprising:

a first acoustical sensor adapted to be operatively positioned in a first internal body location to have a first level of responsiveness for sensing heart sounds in a patient, and to generate a first signal responsive to the sensed heart sounds;

a second acoustical sensor adapted to be operatively positioned in a second internal body location to have a second level of responsiveness for sensing heart sounds in the patient less than the first level of responsiveness, and to generate a second signal responsive to the heart sounds;

a subcutaneously positioned medical device comprising a housing and a processor enclosed in the housing, the processor configured to receive the first signal and the second signal and generate a corrected first signal by cancelling non-cardiac signals in the first signal using the second signal; and

a subcutaneous lead having a distal end and adapted to extend from the subcutaneously positioned medical device to a posterior location,

the first acoustical sensor positioned along a surface of the housing,

the second acoustical sensor positioned proximate the subcutaneous lead distal end.

10. A method for use in an implantable medical device system, comprising:

sensing heart sounds in a patient using a first acoustical sensor positioned in a first internal body location to have a first level of responsiveness for sensing heart sounds in a patient, and to generate a first signal responsive to the sensed heart sounds;

sensing sounds in the patient using a second acoustical sensor positioned in a second internal body location to have a second level of responsiveness for sensing heart sounds in the patient less than the first level of responsiveness, and to generate a second signal responsive to the heart sounds; and

processing the first and second signals to generate a corrected first signal by canceling non-cardiac signals in the first signal using the second signal.

11. The method of claim 10 wherein the processing is performed in response to detecting noise.

12. The method of claim 11 wherein detecting noise comprises detecting noise content of one of the first signal and the second signal.

13. The method of claim 11 wherein detecting noise comprises detecting patient activity.