Adaptive sampling of heart sounds

• US 9,700,726 B2
• Filed: 12/14/2011
• Issued: 07/11/2017
• Est. Priority Date: 11/29/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Haro, Carlos, Patangay, Abhilash, Carlson, Gerrard M., Siejko, Krzysztof Z., Stahmann, Jeffrey E., Belalcazar, Andres
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): Bays, Pamela M
• Application Number:
  US13/325,654
• Publication Number:
  US 20120089040A1
• Time in Patent Office: 2,036 Days
• Field of Search: 607 4, 607 18, 600439, 600485, 600500, 600513, 600514, 600528
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• 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 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• 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

Abstract

A system and method to sense heart sounds with one or more implantable medical devices according to one or more signal processing parameters. The method alters one or more of the parameters as a function of one or more physiologic triggering events. The method then senses heart sounds with the one or more implantable medical devices according to at least the one or more altered signal processing parameters.

Claims

1. A process to control operation of a medical device system, the process comprising:

sensing heart sounds of a subject with a first implantable medical device of the medical device system according to one or more heart sound signal processing parameters, wherein the one or more heart sound signal processing parameters include one or more characteristics of an ensemble average, a bit resolution, a noise blanking interval, and a retry interval;

detecting one or more physiologic triggering events of the subject during the heart sound sensing;

identifying a type of heart sound to sense, from a plurality of heart sound types identifiable by the in implantable medical device, as a function of the one or more detected physiologic triggering events;

adaptively altering, by the medical device system, one or more of the heart sound signal processing parameters of the medical device system in response to the identifying the type of heart sound to sense; and

sensing heart sounds with the implantable medical device according to at least the one or more altered heart sound signal processing parameters.

2. The process of claim 1, wherein altering one or more of the heart sound signal processing parameters includes altering the one or more characteristics of an ensemble average, wherein the characteristics of an ensemble average include one or more of using only sensed heart beats, using only paced heart beats, selecting non-consecutive heart beats;

the number of heart beats, and a threshold amplitude for heart beats.

3. The process of claim 1, wherein altering one or more of the heart sound signal processing parameters includes altering the retry interval, wherein the retry interval is a function of a result of a previous data acquisition.

4. The process of claim 1, further including altering a sampling frequency used in sampling the heart sound, wherein the sampling frequency is a function of a frequency characteristic of an S3 or S4 heart sound.

5. The process of claim 1, wherein altering one or more of the heart sound signal processing parameters includes altering the data sampling interval, wherein the data sampling interval is a function of a time period during a cardiac cycle when a particular heart sound is likely to be present.

6. The process of claim 1, wherein the one or more physiologic triggering events include a function of one or more of a heart rate, a cardiac cycle phase, a respiration rate, a respiration phase, a posture, a time of day, a noise level, an activity level, a patient risk factor, a sleep state, a body weight, a change in patient health status, a predetermined interval, a result of a prior data acquisition, a pacing status, a sensing status, a pressure level, an impedance, a heart rate variability, a heart sound amplitude, a heart sound interval, and a heart sound duration.

7. The process of claim 6, wherein the patient risk factor includes one or more of a heart failure decompensation risk factor, an increase in an occurrence or intensity of one or more of an S3 heart sound and an S4 heart sound, and an occurrence or change in a splitting of an S1 heart sound, and an occurrence or change in a splitting of an S2 heart sound.

8. The process of claim 1, wherein the altering of the one or more parameters as a function of the one or more physiologic triggering events includes using one or more of an onset, a termination, an increase, a decrease, a presence, an absence, and a rate of change of the one or more physiologic trigger events.

9. The process of claim 1, further comprising returning to the sensing of heart sounds according to a previous set of parameters upon a change in one or more of the physiologic triggering events.

10. The process of claim 1, comprising one or more of terminating, initiating, increasing, and decreasing sampling of a heart sound signal or processing of the heart sound signal in response to the one or more physiologic triggering events.

11. The process of claim 1, comprising changing a processing location between the first implantable device and one or more of a second implantable device and an external device as a function of one or more of the physiologic triggering events.

12. The process of claim 1, comprising telemetering heart sound data to one or more of another implantable device, an external device, and an external database as a function of one or more of the physiologic triggering events.

13. The process of claim 1, comprising synchronizing the sensing of the heart sounds with another physiological event as a function of one or more of the physiologic triggering events.

14. The process of claim 13, wherein the physiological event includes an event related to one or more of respiration, posture, sleep state, circadian rhythm, paced heart beats, sensed heart beats, and heart rate.

15. A process of controlling an implantable medical device, the process comprising:

sensing heart sounds with the implantable medical device according to one or more heart sound signal processing parameters;

identifying a type of heart sound to sense, from a plurality of heart sound types identifiable by the implantable medical device, as a function of one or more physiologic triggering events that include a patient risk factor detected during the heart sound sensing; and

adaptively selecting, by self-configuring of the implantable medical device, a first value of a heart sound signal sampling frequency when the identified type of heart sound is a first heart sound type, and selecting a second different value of the heart sound signal sampling frequency when the identified type of heart sound is a second different heart sound type.

16. The process of claim 15, wherein selecting a heart sound signal sampling frequency according to the identified heart sound includes selecting a first signal sampling frequency when the identified heart sound is an S3 heart sound and selecting a second different signal sampling frequency when the identified heart sound is an S1 heart sound.

17. The process of claim 15, wherein selecting a heart sound signal sampling frequency according to the identified heart sound includes selecting a first signal sampling frequency for the identified heart sound at a first determined heart rate and selecting a second different sampling frequency for the identified heart sound at a second determined heart rate.