Extravascular hemodynamic acoustic sensor

• US 6,477,406 B1
• Filed: 04/05/2000
• Issued: 11/05/2002
• Est. Priority Date: 11/10/1999
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Turcott, Robert
• Primary Examiner(s): Layno, Carl
• Application Number:
  US09/543,394
• Time in Patent Office: 944 Days
• Field of Search: 600/518, 607/17, 607/36
• US Class Current: 600/518
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/6816 Ear lobe
• CPC Class Codes: A61B 5/6817 Ear canal
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61N 1/36535 controlled by body position or posture
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• 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 1/36585 controlled by two or more physical parameters

Abstract

An implantable medical device such as a pacemaker or implantable cardioverter defibrillator or stand-alone hemodynamic monitor that uses an acoustic transducer responsive to heart sounds to detect the hemodynamic status of a patient. A hermetic housing encloses the device electronics and the device housing includes at least one substantially planar face configured to act as a diaphragm in response to acoustic waves. A transducer positioned inside the device housing provides an output signal to the device electronics responsive to vibration of the diaphragm. Embodiments of the transducer include a piezoelectric element and laser interferometer. The hemodynamic information may be used in various ways including arrhythmia discrimination and pacing and sensing optimization.

Claims

1. An implantable medical device including a sensor for use in detecting the hemodynamic status of a patient comprising:

a hermetic device housing enclosing device electronics for receiving and processing data;

said device housing including at least one substantially planar face configured to act as a diaphragm in response to acoustic waves; and

a transducer positioned inside said device housing to provide an output signal to said device electronics responsive to vibration of said diaphragm.

2. The implantable medical device of claim 1 wherein said transducer comprises a piezoelectric element positioned on said diaphragm.

3. The implantable medical device of claim 1 wherein said transducer comprises a laser interferometery source and detector having a laser light reflecting off of said diaphragm.

4. An implantable medical device including a hemodynamic sensor for monitoring pulse amplitude comprising:

a device housing; and

a transducer comprising a laser interferometer positioned inside said device housing responsive to heart sounds.

5. An implantable medical device comprising:

a device housing;

a transducer associated with said device housing responsive to heart sounds;

electronic circuitry for controlling said medical device and coupled to receive sensed heart sound signals from said transducer and for processing said sensed heart sound signals and controlling said device in response thereto; and

an accelerometer wherein said accelerometer detects motion artifacts that could interfere with said sensed heart sound signals.

6. The medical device of claim 5 wherein said electronic circuitry uses said sensed heart sound signals to discriminate among possible cardiac arrhythmias.

7. The medical device of claim 5 wherein said sensed heart sound signals are analyzed for the presence of noise artifacts.

8. The medical device of claim 5 wherein said medical device is an implantable pulse generator for providing pacing therapy to a patient'"'"'s heart and wherein said electronic circuitry uses said sensed heart sound signals to optimize the timing of pacing pulses provided to said patient'"'"'s heart.

9. An implantable pulse generator for providing pacing therapy to a patient'"'"'s heart comprising:

a device housing;

a transducer associated with said device housing responsive to heart sounds;

a posture sensor; and

electronic circuitry to control said pulse generator coupled to receive sensed heart sound signals from said transducer and posture sensor signals from said posture sensor, said electronic circuitry processing said sensed heart sound signals and said posture signal wherein the timing of pacing pulses provided to said patient'"'"'s heart is optimized using said sensed heart sound signals upon sensing of a change of the patient'"'"'s posture by said posture sensor.

10. An implantable medical device comprising:

a device housing;

a sensing lead for coupling to said patient'"'"'s heart to sense electrical signals from the heart;

a transducer associated with said device housing responsive to heart sounds; and

electronic circuitry to control said medical device and coupled to receive sensed heart sound signals from said transducer, said electronic circuitry processing said sensed heart sound signals;

wherein said electronic circuitry uses said sensed heart sound signals to optimize electrical sensing with said sensing lead.