METHODS AND SYSTEMS FOR IDENTIFYING AND USING HEART RATE VARIABILITY AND HEART RATE VARIATION

• US 20130150912A1
• Filed: 12/06/2012
• Published: 06/13/2013
• Est. Priority Date: 12/12/2011
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Perschbacher, David L., Sharma, Arjun D., Stolen, Craig, Seth, Milan, Stolen, Kira Q., Jones, Paul W.
• Granted Patent: US 8,929,981 B2
• Time in Patent Office: Days
• US Class Current: 607/18
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• 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: A61N 1/36507 controlled by gradient or slope of the heart potential
• CPC Class Codes: A61N 1/36535 controlled by body position or posture
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/36592 controlled by the heart rate variability

Abstract

A heart rate variability or heart rate variation can be identified using sensed and/or paced heart beats. One or more patient metrics, such as a variability index or a variation index, can correspond to the identified heart rate variability or heart rate variation. The patient metrics can be used to identify a need for a particular therapy, such as a rate-responsive pacing therapy. The patient metrics can be used to identify patients at an elevated risk of death. Methods and systems to identify therapy indications or at-risk patients are provided. In an example, a patient risk profile can be adjusted, such as in response to an identified patient heart rate variability or heart rate variation. In an example, a rate-responsive pacing mode can be used to adjust the patient risk profile.

Claims

1. An apparatus comprising:

a data input circuit configured to receive a cardiac activity signal of a patient, the cardiac activity signal including information about intrinsic and non-intrinsic cardiac activity;

a memory circuit configured to store information about the received cardiac activity signal; and

a processor circuit, coupled to the memory circuit, the processor circuit configured to;

determine a heart rate variability using the stored information about the cardiac activity signal including information about intrinsic and non-intrinsic cardiac activity; and

determine a rate-responsive pacing mode suitability indication for the patient using the determined heart rate variability.

2. The apparatus of claim 1, wherein the processor circuit is configured to determine the heart rate variability using patient heart rate information obtained from the stored information about the cardiac activity signal, including using patient heart rate information that includes information about both intrinsic and non-intrinsic patient heart beats, wherein the heart rate variability is indicative of a number of both intrinsic and non-intrinsic patient heart beats within a specified heart rate range.

3. The apparatus of claim 1, wherein the processor circuit is configured to compute a patient metric using the determined heart rate variability.

4. The apparatus of claim 1, wherein the processor circuit is configured to identify a lesser suitability for the rate-responsive pacing mode for the patient when the heart rate variability is at a first heart rate variability value, and identify a greater suitability for the rate-responsive pacing mode for the patient when the heart rate variability is at a second heart rate variability value that is less than the first heart rate variability value.

5. The apparatus of claim 1, wherein the processor circuit is configured to determine whether a count of the patient'"'"'s non-intrinsic heart beats exceeds a specified portion of a total count of the patient'"'"'s intrinsic and non-intrinsic heart beats during a specified period, and, when the count of the patient'"'"'s non-intrinsic heart beats exceeds the specified portion of the total count of the patient'"'"'s intrinsic and non-intrinsic heart beats during the specified period, determine the rate-responsive pacing mode suitability indication for the patient.

6. The apparatus of claim 1, comprising a physiologic sensor configured to provide a signal indicative of the patient'"'"'s metabolic need for a particular level of cardiac output, wherein the rate-responsive pacing mode is capable of automatically adjusting a patient pacing rate as a function of a variation in the signal indicative of the patient'"'"'s metabolic need for the particular level of cardiac output, wherein the physiologic sensor comprises at least one of a patient physical activity level sensor or an impedance sensor.

7. The apparatus of claim 1, comprising a posture detection circuit configured to provide a signal indicative of a patient posture, wherein the processor circuit is configured to determine the rate-responsive pacing mode suitability indication for the patient using the determined heart rate variability and the signal indicative of a patient posture.

8. The apparatus of claim 1, wherein the memory circuit is configured to store patient heart rate information, obtained from the received cardiac activity signal, in a heart rate histogram bin corresponding to a patient heart rate range;

and

wherein the processor circuit is configured to determine the heart rate variability using information about the heart rate histogram.

9. The apparatus of claim 8, wherein the processor circuit is configured to determine the heart rate variability using a morphology characteristic of the heart rate histogram.

10. The apparatus of claim 1, wherein the processor circuit is configured to compute a predictive patient mortality indication using the determined heart rate variability.

11. The apparatus of claim 10, wherein the processor circuit is configured to identify a lesser patient mortality rate for the patient when the heart rate variability is at a first heart rate variability value, and identify a greater patient mortality rate for the patient when the heart rate variability is at a second heart rate variability value that is less than the first heart rate variability value.

12. The apparatus of claim 1, wherein the processor circuit is configured to adjust a patient therapy using the determined heart rate variability.

13. The apparatus of claim 1, wherein the processor circuit is configured to initiate or adjust a rate-responsive pacing mode in a pacemaker in response to the determined heart rate variability.

14. The apparatus of claim 1, wherein the processor circuit is configured to adjust, in response to the determined heart rate variability, at least one of:

a maximum pacing rate that controls a maximum rate at which a pacemaker supplies pacing energy to a heart;

a lower rate limit that controls at which heart rate a pacemaker begins to supply pacing energy to a heart;

a patient physical activity level threshold that controls at which patient physical activity level a pacing energy is initiated or adjusted;

a rate-response reaction time that controls how quickly a pacing rate increases;

a rate-response response factor that controls a pacing rate as a function of a patient physical activity level;

or

a rate-response recovery time that controls a rate at which a pacing rate decreases from a maximum pacing rate to a lower rate limit when a patient physical activity level is less than a specified threshold physical activity level.

15. The apparatus of claim 1, wherein the processor circuit is configured to automatically provide a recommendation for a cardiac rhythm management device using the determined heart rate variability.

16. A method comprising:

obtaining heart rate variability of a patient, including information about both intrinsic and non-intrinsic patient cardiac activity;

analyzing the heart rate variability using a processing device; and

using the analysis of the heart rate variability, determining, using the processing device, a rate-responsive pacing mode suitability indication for the patient.

17. The method of claim 16, comprising programming an operating mode of an ambulatory cardiac function management device using the determined rate-responsive pacing mode suitability indication;

wherein the using the analysis of the heart rate variability comprises identifying a lesser suitability for a rate-responsive pacing mode for the patient when the heart rate variability is at a first heart rate variability value, and identifying a greater suitability for the rate-responsive pacing mode for the patient when the heart rate variability is at a second heart rate variability value that is less than the first heart rate variability value.

18. The method of claim 16, comprising determining the rate-responsive pacing mode suitability indication for the subject when the analysis of the heart rate variability indicates that, during a specified period, a count of the subject'"'"'s non-intrinsic heart beats exceeds a specified portion of a total count of the subject'"'"'s intrinsic and non-intrinsic heart beats.

19. The method of claim 16, comprising providing a predictive patient mortality indication using the determined heart rate variability.

20. An apparatus comprising:

a data input circuit configured to receive information indicative of a patient heart rate including information about both intrinsic and non-intrinsic patient heart beats;

a memory circuit configured to store information about the patient heart rate over time; and

a processor circuit, coupled to the memory circuit, the processor circuit configured to;

determine a heart rate variability using the stored information about the patient heart rate over time, the determined heart rate variability indicative of a number of both intrinsic and non-intrinsic patient heart beats within a specified heart rate range;

determine a rate-responsive pacing mode suitability indication for the patient using the determined heart rate variability, including identifying a lesser suitability for the rate-responsive pacing mode for the patient when the heart rate variability is at a first heart rate variability value, and identifying a greater suitability for the rate-responsive pacing mode for the patient when the heart rate variability is at a second heart rate variability value that is less than the first heart rate variability value; and

update a rate-responsive pacing mode in a pacemaker using the determined rate-responsive pacing mode suitability indication.