ADAPTIVE SAMPLING OF HEART SOUNDS

• US 20080125820A1
• Filed: 11/29/2006
• Published: 05/29/2008
• 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: Belalcazar, Andres, Patangay, Abhilash, Carlson, Gerrard M., Stahmann, Jeffrey E., Siejko, Krzysztof Z., Haro, Carlos
• Granted Patent: US 8,096,954 B2
• Time in Patent Office: Days
• US Class Current: 607/4
• 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 parameters. The system alters one or more of the parameters as a function of one or more triggering events. The system then senses heart sounds with the one or more implantable medical devices according to at least the one or more altered parameters.

Claims

1. A system comprising:

a first implantable medical device comprising;

a control circuit;

a parameter circuit, coupled to the control circuit, the parameter circuit comprising one or more parameters;

a sensor, coupled to the control circuit, the sensor configured to sense energy and produce a signal indicative of heart sounds;

a heart sound detector, coupled to the control circuit, the heart sound detector adapted to detect heart sounds within the signal; and

a triggering circuit, coupled to the control circuit, the triggering circuit configured to transmit a signal to the control circuit upon the occurrence of a triggering event;

wherein the sensor senses energy including heart sounds sensed by the heart sound detector as a function of the one or more parameters; and

further wherein the triggering circuit signal causes a change in one or more of the parameters.

2. The system of claim 1, wherein the sensor is an acoustic sensor that senses acoustic energy and produces an acoustic signal.

3. The system of claim 1, wherein the parameters include one or more of a sampling frequency, a data acquisition separation interval, a data acquisition interval, one or more characteristics of an ensemble average, a bit resolution, a noise blanking interval, and a retry interval.

4. The system of claim 1, wherein the one or more triggering events is 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 patient input, a care giver input, a body weight, a change in 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, a heart sound duration, and a clinic visit.

5. The system of claim 4, wherein the patient risk factor includes one of 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 or an occurrence or change in a splitting of an S2 heart sound.

6. The system of claim 1, wherein the triggering circuit transmits the signal as a function of one or more of an onset, a termination, an increase, a decrease, a presence, an absence, a probability of occurrence, a probability of frequency, and a rate of change of the one or more triggering events.

7. The system of claim 1, further comprising:

a telemetry circuit coupled to the control circuit; and

an external device wirelessly coupled to the telemetry circuit;

wherein the telemetry circuit is configured to include one or more of the functions of transmitting and receiving one or more of data related to the use of and acquisition of heart sound data.

8. The system of claim 7, further comprising an external data base coupled to the external device, the external data base for receiving and storing the heart sound data.

9. The system of claim 1, further comprising:

a telemetry circuit coupled to the control circuit; and

a second implantable medical device;

wherein the telemetry circuit communicatively couples the first and second implantable medical devices.

10. The system of claim 9, further comprising a therapy circuit, wherein the therapy circuit is configured to provide therapy to a patient.

11. The system of claim 10, wherein the therapy circuit is configured to provide one or more of pacing, defibrillation, cardioversion, cardiac resynchronization, and neural stimulation therapy.

12. A process comprising:

sensing heart sounds with a first implantable medical device according to one or more parameters;

altering one or more of the parameters as a function of one or more triggering events; and

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

13. The process of claim 12, wherein the altering one or more of the parameters includes altering one or more of a sampling frequency, a data acquisition separation interval, a data acquisition interval, one or more characteristics of an ensemble average, a bit resolution, a noise blanking interval, and a retry interval.

14. The process of claim 13, 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.

15. The process of claim 13, wherein the retry interval is a function of a result of a previous data acquisition.

16. The process of claim 13, wherein the altering the sampling frequency is a function of a frequency characteristic of a particular heart sound to be sensed.

17. The process of claim 13, 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.

18. The process of claim 12, wherein the one or more triggering events is 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 patient input, a care giver input, a body weight, a patient health status, a predetermined interval, a result of a prior data acquisition, a pacing status, a sensing status, a pressure level, an impedance, and a clinic visit.

19. The process of claim 18, 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 or an S2 heart sound.

20. The process of claim 12, wherein the altering of the one or more parameters as a function of the one or more 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 trigger events.

21. The process of claim 12, 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 triggering events.

22. The process of claim 12, comprising one or more of terminating, initiating, increasing, and decreasing heart sound sampling or processing in response to the one or more triggering events.

23. The process of claim 12, 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 triggering events.

24. The process of claim 12, 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 triggering events.

25. The process of claim 12, comprising synchronizing the sensing of the heart sounds with a physiological event as a function of one or more of the triggering events.

26. The process of claim 25, wherein the physiological event includes one or more of respiration, posture, sleep state, circadian rhythm, paced heart beats, sensed heart beats, and heart rate.