Methods for detecting atrial tachyarrhythmia in implantable devices without dedicated atrial sensing

• US 9,510,764 B2
• Filed: 04/06/2010
• Issued: 12/06/2016
• Est. Priority Date: 04/22/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Li, Dan, Perschbacher, David L., Dong, Yanting, Stephenson, Julie
• Primary Examiner(s): Alter, Alyssa M
• Application Number:
  US12/754,932
• Publication Number:
  US 20100274149A1
• Time in Patent Office: 2,436 Days
• Field of Search: 600/518
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/3624 occurring in the atrium, i.e. atrial tachycardia
• CPC Class Codes: A61N 1/36592 controlled by the heart rate variability

Abstract

An apparatus comprises an implantable cardiac signal sensing circuit configured to provide a sensed depolarization signal from a ventricle and a processor. The processor includes a signal analyzer module and a tachyarrhythmia discrimination module. The signal analyzer module is configured to determine a measure of stability of ventricular (V-V) depolarization intervals using the depolarization signal, and determine a rate of change of the measure of stability. The tachyarrhythmia discrimination module is configured to detect an episode of tachyarrhythmia using the depolarization signal, determine whether the detected tachyarrhythmia is indicative of atrial tachyarrhythmia using the determined rate of change, and provide the determination to a user or process.

Claims

1. An apparatus comprising:

an implantable cardiac signal sensing circuit, configured to provide a sensed depolarization signal from a ventricle; and

a processor communicatively coupled to the cardiac signal sensing circuit, the processor including;

an signal analyzer module configured to;

determine a measure of stability of ventricular (v-V) depolarization intervals using the depolarization signal; and

determine a rate of change of the measure of stability of V-V depolarization intervals; and

a tachyarrhythmia discrimination module configured to;

detect an episode of tachyarrhythmia using the depolarization signal;

determine whether the detected tachyarrhythmia is indicative of atrial tachyarrhythmia in an absence of a dedicated atrial chamber sensing using the determined rate of change of the measure of stability of V-V depolarization intervals; and

provide the determination to a user or process.

2. The apparatus of claim 1, wherein the tachyarrhythmia discrimination module is configured to classify the detected tachyarrhythmia as atrial tachyarrhythmia when the rate of change of the measure of stability exceeds an atrial tachyarrhythmia rate of change detection threshold.

3. The apparatus of claim 1, wherein the tachyarrhythmia discrimination module is configured to classify the detected tachyarrhythmia as ventricular tachyarrhythmia when the rate of change of the measure of stability is greater than a ventricular tachyarrhythmia rate of change detection threshold and is less than the atrial tachyarrhythmia rate of change detection threshold.

4. The apparatus of claim 1,

wherein the signal analyzer module is configured to determine a rate of change of the measure of stability when a ventricular depolarization rate or interval satisfies a specified threshold rate or threshold interval value;

and

wherein the tachyarrhythmia discrimination module is configured to;

classify the detected tachyarrhythmia according to the rate of change of the measure of stability when the ventricular rate or interval satisfies the specified threshold value; and

classify the detected tachyarrhythmia according to the measure of stability otherwise.

5. The apparatus of claim 1, including:

a memory communicatively coupled to the processor and configured to a store a signal morphology template;

a far-field sensing channel configured to provide afar-field atrial and ventricular signal using an electrode location that is outside of an atrium or ventricle, and

wherein the tachyarrhythmia discrimination module is configured to;

upon determining the detected tachyarrhythmia is atrial tachyarrhythmia, initiate sensing of the far-field signal;

initiate a comparison of a morphology of the sensed far-field signal to a stored morphology template by the signal analyzer module; and

confirm the classification as atrial tachyarrhythmia using the morphology comparison.

6. The apparatus of claim 5, wherein the signal analyzer module is configured to:

calculate a measure of similarity between a segment of the far-field signal and the morphology template, wherein the stored morphology template is representative of normal sinus rhythm;

calculate a central tendency of the measure of similarity and a variance of the measure of similarity, and

wherein the tachyarrhythmia discrimination module is configured to confirm the classification as atrial tachyarrhythmia when the central tendency of the measure of similarity is above a central tendency threshold and the variance of the measure of similarity is within a variance range.

7. The apparatus of claim 5, wherein the stored morphology template is associated with atrial tachyarrhythmia.

8. The apparatus of claim 1, including:

a memory communicatively coupled to the processor; and

a communication circuit, communicatively coupled to the processor, configured to communicate information wirelessly with a second separate device, and

wherein the tachyarrhythmia discrimination module is configured to;

upon classifying the detected tachyarrhythmia as atrial tachyarrhythmia, initiate storage of a segment of the depolarization signal when a duration of the detected tachyarrhythmia exceeds a duration threshold;

initiate storage of a histogram of V-V depolarization intervals, wherein the histogram indicates regular and irregular V-V depolarization intervals; and

communicate the stored segment and histogram to a second device.

9. The apparatus of claim 1, including:

a far-field sensing channel configured to provide a far-field atrial signal using an electrode location that is outside of an atrium;

a memory communicatively coupled to the processor; and

a communication circuit, communicatively coupled to the processor, configured to communicate information wirelessly with a second separate device, and

wherein the tachyarrhythmia discrimination module is configured to;

upon classifying the detected tachyarrhythmia as atrial tachyarrhythmia, initiate storage of a segment of the sensed far-field signal when a duration of the detected arrhythmia exceeds a duration threshold;

communicate the stored segment to the second device for comparison of a far-field signal morphology to a morphology template; and

receive an indication whether the detected tachyarrhythmia is atrial tachyarrhythmia from the second device.

10. The apparatus of claim 1, wherein the tachyarrhythmia discrimination module is configured to:

detect an episode of atrial fibrillation (AF) using the depolarization signal;

determine a duration that the subject spends in AF; and

calculate a value of AF burden using the duration that the subject spends in AF.

11. The apparatus of claim 10, wherein the tachyarrhythmia discrimination module is configured to generate AF histogram data and communicate the histogram data to a separate device.

12. A method comprising:

detecting an episode of tachyarrhythmia from a depolarization signal sensed from a ventricle using a dedicated implantable ventricular sensing circuit and in an absence of a dedicated atrial chamber sensing circuit;

determining a measure of stability of V-V depolarization intervals using the depolarization signal;

determining a rate of change of the measure of stability;

classifying the detected tachyarrhythmia to discriminate between atrial tachyarrhythmia and ventricular tachyarrhythmia using the determined rate of change of the measure of stability of V-V depolarization intervals; and

providing the tachyarrhythmia classification to a user or process.

13. The method of claim 12, wherein classifying the detected tachyarrhythmia includes classifying the detected tachyarrhythmia as atrial tachyarrhythmia when the rate of change of the measure of stability exceeds an atrial tachyarrhythmia rate of change detection threshold.

14. The method of claim 13, wherein classifying the detected tachyarrhythmia includes classifying the detected tachyarrhythmia as ventricular tachyarrhythmia when the rate of change of the measure of stability is greater than a ventricular tachyarrhythmia rate of change detection threshold and is less than the atrial tachyarrhythmia rate of change detection threshold.

15. The method of claim 12,

wherein determining a rate of change of the measure of stability includes determining a rate of change of the measure of stability when the ventricular rate or interval satisfies a threshold rate or interval value;

and

wherein classifying the detected tachyarrhythmia includes;

classifying the detected tachyarrhythmia according to the rate of change of the measure of stability when the ventricular rate or interval satisfies the threshold rate or interval value; and

classifying the detected tachyarrhythmia according to the measure of stability otherwise.

16. The method of claim 12, including:

upon classifying the detected tachyarrhythmia as atrial tachyarrhythmia, sensing a second signal using a far-field sensing channel; and

comparing a morphology of the second sensed signal to a morphology template, and

wherein classifying the tachyarrhythmia includes confirming the classification as atrial tachyarrhythmia using the morphology comparison.

17. The method of claim 16, wherein classifying the tachyarrhythmia includes

calculating a measure of similarity between a segment of the second signal and the morphology template, wherein the morphology template is representative of normal sinus rhythm;

calculating a central tendency of the measure of similarity and a variance of the measure of similarity, and

wherein confirming the classification includes confirming the classification as atrial tachyarrhythmia when the central tendency of the measure of similarity is above a central tendency threshold and the variance of the measure of similarity is within a variance range.

18. The method of claim 16, including:

upon classifying the detected tachyarrhythmia as atrial tachyarrhythmia, storing a segment of the second signal when a duration of the detected arrhythmia exceeds a duration threshold,

wherein comparing a morphology includes communicating the stored segment from a first implantable medical device to a second device and comparing the morphology of the second sensed signal to the morphology template using the second device, and

wherein confirming the classification includes confirming the classification as atrial tachyarrhythmia using the morphology comparison by the second device.

19. The method of claim 16, wherein comparing a morphology of the second signal includes comparing a morphology of the second sensed signal to a morphology template associated with atrial tachyarrhythmia.

20. The method of claim 12, including

upon classifying the detected tachyarrhythmia as atrial tachyarrhythmia, storing a segment of the depolarization signal when a duration of the detected tachyarrhythmia exceeds a duration threshold;

storing a histogram of V-V depolarization intervals, wherein the histogram indicates regular and irregular V-V depolarization intervals; and

communicating the stored segment and histogram from an implantable medical device to a second device.