Risk stratification based heart failure detection algorithm

Patent metadata

Field	Value
Publication number	US-9968266-B2
Application number	US-201213726786-A
Country	US
Kind code	B2
Filing date	Dec 26, 2012
Priority date	Dec 27, 2006
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A system comprises a risk analysis module and a worsening heart failure (WHF) detection module. The risk analysis module measures at least one first physiological parameter of a subject using a physiological sensor of an ambulatory medical device, and determines a heart failure (HF) risk score for the subject according to the at least one measured first physiological parameter. The HF risk score indicates susceptibility of the subject to experiencing a HF event. The WHF detection module measures at least one second physiological parameter of the subject using the same or different physiological sensor, and generates an indication of prediction that the subject will experience a WHF event when the at least one second physiological parameter satisfies a WHF detection algorithm. The risk analysis module adjusts generation of the indication by the WHF detection algorithm according to the determined HF risk score.

First claim

What is claimed is:

1. A system comprising:
one or more ambulatory medical devices, wherein a first ambulatory medical device includes a heart sound sensor configured to sense an S3 heart sound of a subject; and a processor, wherein the processor includes:

a control module configured to:
detect worsening heart failure (WHF) for the subject using a WHF detection scheme, wherein the WHF detection scheme includes comparing one or more measured heart failure (HF) physiological parameter parameters to a WHF detection threshold; and
store, in the memory, an alert of prediction that the subject will experience a WHF event when the one or more measured HF physiological parameter satisfies the WHF detection scheme; and
a risk analysis module configured to:
measure a first physiological parameter of the sensed S3 heart sound, wherein the first physiological parameter is distinct from the one or more measured HF physiological parameter parameters;
determine a HF risk score for the subject according to the at least one measured first physiological parameter in response to detecting the change, and determine whether the HF risk score indicates high risk for WHF or low risk for WHF; and
adjust one or more of the WHF detection scheme threshold, a weighting of the one or more measured HF physiological parameters, or a number of the one or more measured HF parameters that are compared to the WHF detection threshold according to the determined HF risk score to increase sensitivity of the WHF detection scheme when high risk for WHF is indicated and increase specificity of the WHF detection scheme when low risk for WHF is indicated;

wherein the one or more measured HF physiological parameters includes at least one of heart rate (HR), respiration rate (RR), tidal volume (TV), intrathoracic impedance (ITTI), or one or more of heart sound (HS) timing or amplitude distinct from the measured first physiological parameter.

2. The system of claim 1 , wherein the control module is configured to generate the indication of prediction of a WHF event when the HF physiological parameter satisfies at least one detection criterion of the WHF detection scheme, and wherein the risk analysis module is configured to adjust the at least one detection criterion of the WHF detection scheme according to the determined HF risk score.

3. The system of claim 2 , wherein the risk analysis module is configured to continuously vary at least one parameter of the WHF detection scheme as a function of the at least one first physiological parameter measurement.

4. The system of claim 1 , wherein the risk analysis module is configured to select a detection scheme as the WHF detection scheme from among a plurality of detection schemes according to the determined HF risk score.

5. The system of claim 1 , including:
wherein an ambulatory medical device of the one or more ambulatory medical devices includes at least one of:
a respiration sensor and wherein the at least one first physiological parameter further includes a measured day-to-day variation in respiratory rate of the subject;
a cardiac signal sensing circuit and wherein the at least one first physiological parameter further includes a time interval measured between two fiducial features occurring in one or more cardiac cycles;
a biomarker sensor configured to generate an indication or a surrogate indication of a biomarker indicative of a WHF event, and wherein the at least one first physiological parameter further includes at least one of a direct measure or a surrogate measure of the biomarker;
a jugular vein distention (JVD) sensor configured to generate an indication of JVD or a surrogate indication of JVD and wherein the at least one first physiological parameter further includes a measurement representative of JVD; and
a counter circuit and a timer circuit, and wherein the at least one first physiological parameter further includes a number of HF events detected for the subject within a specified time window.

6. The system of claim 1 , wherein the risk analysis module is configured to:
measure a plurality of physiological parameters that are distinct from the HF physiological parameter; and
determine the HF risk score using the plurality of physiological parameters.

7. The system of claim 6 , including:
a scoring module configured to determine individual reliability scores for each of the plurality of physiological parameters, wherein a higher reliability score is assigned to a physiological parameter having a more consistent measurement; and
wherein the risk analysis module is configured to combine the individual HF risk scores according to the determined reliability scores to form a composite HF risk score.

8. The system of claim 7 , wherein the scoring module is configured to discard a HF risk score for a physiological parameter measurement when a reliability score determined for the physiological parameter measurement falls below a specified reliability score threshold value.

9. The system of claim 1 , including:
a user interface in electrical communication with the risk analysis module, wherein the risk analysis module is configured to:
receive an indication of severity of an HF condition of the subject via the user interface; and
determine the HF risk score according to the first physiological parameter measurement and the received indication of severity.

10. The system of claim 1 , including:
the first ambulatory medical device, wherein the first ambulatory medical device performs the WHF detection scheme;
an external medical device, wherein the external medical device includes the risk analysis module and a communication module in electrical communication with the risk analysis module, wherein the communication module is configured to communicate information with the ambulatory medical device, and wherein the risk analysis module is configured to communicate an adjustment to the WHF detection scheme to the first ambulatory medical device.

11. The system of claim 1 , wherein the control module is configured to adjust a device-based therapy when the measured HF physiological parameter satisfies the adjusted WHF detection scheme.

12. A method of operation of a medical device system, the method comprising:
sensing an S3 heart sound of a subject using a heart sound sensor of a first ambulatory medical device;
detecting worsening heart failure (WHF) for the subject using a WHF detection scheme, wherein the WHF detection scheme that compares one or more measured heart failure (HF) physiological parameter parameters to a WHF detection threshold;
measuring at least one a first physiological parameter of the sensed S3 heart sound of a subject using a physiological sensor of an ambulatory medical device, wherein the first S3 heart sound is distinct from the one or more measured HF parameters;
detecting a change in the at least one first physiological parameter that exceeds a specified parameter change value;
determining a heart failure (HF) risk score for the subject according to the measured at least one first physiological parameter in response to detecting the change, and determine whether the HF risk score indicates high risk for WHF or low risk for WHF;
adjusting, by the medical device system, one or more of the WHF detection scheme threshold, a weighting of the one or more measured HF physiological parameters, or a number of the one or more measured HF parameters that are compared to the WHF detection threshold according to a comparison of the determined HF risk score to a HF risk score threshold value to increase sensitivity of the WHF detection scheme when high risk for WHF is indicated and increase specificity of the W

Assignees

• Cardiac Pacemakers Inc

Inventors

• An Qi
• Thakur Pramodsingh Hirasingh
• Averina Viktoria A
• Zhang Yi
• Sweeney Robert J

Classifications

• G06Q50/22

  Social work or social welfare, e.g. community support activities or counselling services · CPC title

• A61B5/02007

  Evaluating blood vessel condition, e.g. elasticity, compliance · CPC title

• G16H50/20

  for computer-aided diagnosis, e.g. based on medical expert systems · CPC title

• G06Q10/00

  Administration; Management · CPC title

• A61N1/37282

  characterised by communication with experts in remote locations using a network · CPC title