METHODS AND SYSTEMS FOR RECOGNIZING ARRHYTHMIAS USING NEURAL STIMULATION

• US 20110218586A1
• Filed: 02/02/2011
• Published: 09/08/2011
• Est. Priority Date: 03/03/2010
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Li, Dan
• Granted Patent: US 8,903,490 B2
• Time in Patent Office: Days
• US Class Current: 607/14
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

In various method embodiments for classifying an arrhythmia, a characteristic of a ventricle is sensed before delivering a diagnostic neural stimulation. The diagnostic neural stimulation is delivered, and the characteristic of the ventricle is sensed while delivering the diagnostic neural stimulation. The sensed characteristic of the ventricle before and during the diagnostic neural stimulation is used to classify the arrhythmia as either a supraventricular tachyarrhythmia (SVT) or a ventricular tachycardia (VT). According to various embodiments, the characteristic of the ventricle is ventricular rate, similarity values of sensed ventricular morphology to a normal sinus rhythm (NSR), or ventricular hemodynamics. Various embodiments use ventricular rate regularity before and during the diagnostic neural stimulation to classify an SVT as atrial fibrillation (AF) or as another SVT.

Claims

1. A method for classifying an arrhythmia, comprising:

sensing a characteristic of a ventricle before delivering a diagnostic neural stimulation;

delivering the diagnostic neural stimulation;

sensing the characteristic of the ventricle while delivering the diagnostic neural stimulation; and

using the sensed characteristic of the ventricle before and during the diagnostic neural stimulation to classify the arrhythmia as either a supraventricular tachyarrhythmia (SVT) or a ventricular tachycardia (VT).

2. The method of claim 1, wherein:

sensing the characteristic of the ventricle before delivering the diagnostic neural stimulation includes sensing a ventricular rate before delivering the diagnostic neural stimulation;

sensing the characteristic of the ventricle while delivering the diagnostic neural stimulation includes sensing the ventricular rate while delivering the diagnostic neural stimulation; and

using the sensed characteristic of the ventricle before and during the diagnostic neural stimulation to classify the arrhythmia includes using the ventricular rate before and during the diagnostic neural stimulation to classify the arrhythmia as either the SVT or the VT.

3. The method of claim 2, wherein using the ventricular rate before and during the diagnostic neural stimulation to classify the arrhythmia as either the SVT or the VT includes determining if a change in the ventricular rate is more than a threshold, and classifying the arrhythmia as the SVT if the change is more than the threshold.

4. The method of claim 3, wherein determining if the change in the ventricular rate is more than a threshold includes determining if a percent change in the ventricular rate is more than a percent change threshold.

5. The method of claim 2, wherein:

sensing the characteristic of the ventricle before delivering the diagnostic neural stimulation further includes sensing a ventricular rate regularity before delivering the diagnostic neural stimulation;

sensing the characteristic of the ventricle while delivering the diagnostic neural stimulation further includes sensing the ventricular rate regularity while delivering the diagnostic neural stimulation; and

using the sensed characteristic of the ventricle before and during the diagnostic neural stimulation to classify the arrhythmia further includes, if the arrhythmia is classified as the SVT, using the ventricular rate regularity before and during the diagnostic neural stimulation to classify the SVT as atrial fibrillation (AF) or as another SVT.

6. The method of claim 5, wherein using the ventricular rate regularity before and during the diagnostic neural stimulation to classify the SVT as either the AF or another SVT includes determining if a change in the ventricular rate regularity is more than a threshold, and classifying the arrhythmia as the AF if the change is more than the threshold.

7. The method of claim 6, wherein determining if the change in the ventricular rate regularity is more than a threshold includes determining if a percent change in the ventricular rate regularity is more than a percent change threshold.

8. The method of claim 1, wherein:

sensing the characteristic of the ventricle before delivering the diagnostic neural stimulation includes sensing a ventricular morphology before delivering the diagnostic neural stimulation and comparing the sensed ventricular morphology to a normal sinus rhythm (NSR) to determine a similarity value (S_PRE);

sensing the characteristic of the ventricle while delivering the diagnostic neural stimulation includes sensing a ventricular morphology while delivering the diagnostic neural stimulation and comparing the sensed ventricular morphology to the NSR to determine a similarity value (S_POST); and

using the sensed characteristic of the ventricle before and during the diagnostic neural stimulation to classify the arrhythmia includes using the S_PRE and the S_POST to classify the arrhythmia as either the SVT or the VT.

9. The method of claim 8, wherein using the S_PRE and the S_POST to classify the arrhythmia as either the SVT or the VT includes classifying the arrhythmia as the SVT if S_POST is greater than a first threshold (TH₁) or if the S_POST is greater than a second threshold (TH₂) and the difference between S_POST and S_PRE is greater than a third threshold (TH₃).

10. The method of claim 1, wherein:

sensing the characteristic of the ventricle before delivering the diagnostic neural stimulation includes sensing ventricular hemodynamics (V HEMO_PRE) before delivering the diagnostic neural stimulation;

sensing the characteristic of the ventricle while delivering the diagnostic neural stimulation includes sensing ventricular hemodynamics (V HEMO_POST) while delivering the diagnostic neural stimulation; and

using the sensed characteristic of the ventricle before and during the diagnostic neural stimulation to classify the arrhythmia includes using V HEMO_PRE and V HEMO_POST to classify the arrhythmia as either the SVT or the VT.

11. The method of claim 1, wherein delivering the diagnostic neural stimulation includes transvascularly stimulating a vagus nerve or a cardiac branch of the vagus nerve.

12. The method of claim 1, wherein delivering the diagnostic neural stimulation includes stimulating a baroreflex response.

13. A system for classifying an arrhythmia, comprising:

an arrhythmia discriminator configured to discriminate between ventricular tachycardia (VT) and supraventricular tachycardia (SVT);

a neural stimulator configured to generate a neural stimulation signal and deliver the neural stimulation signal to an autonomic neural target; and

a controller operably connected to the arrhythmia discriminator and the neural stimulator, wherein the controller is configured to control the neural stimulator to deliver a diagnostic neural stimulation, and to classify the arrhythmia as either the SVT or the VT based on a ventricle characteristic before the diagnostic neural stimulation and a ventricle characteristic during the diagnostic neural stimulation.

14. The system of claim 13, wherein:

the ventricle characteristic before delivering the diagnostic neural stimulation includes a ventricular rate before delivering the diagnostic neural stimulation;

the ventricle characteristic while delivering the diagnostic neural stimulation includes the ventricular rate while delivering the diagnostic neural stimulation; and

the controller is configured to classify the arrhythmia using the ventricular rate before and the ventricular rate during the diagnostic neural stimulation to classify the arrhythmia as either the SVT or the VT.

15. The system of claim 14, wherein the controller is configured to determine if a change in the ventricular rate is more than a threshold, and classify the arrhythmia as the SVT if the change is more than the threshold.

16. The system of claim 15, wherein the controller is configured to determine if a percent change in the ventricular rate is more than a percent change threshold.

17. The system of claim 14, wherein the controller is configured to use ventricular rate regularity before and during the diagnostic neural stimulation to classify the SVT as either atrial fibrillation (AF) or as another SVT.

18. The system of claim 17, wherein the controller is configured to determine if a change in the ventricular rate regularity is more than a threshold, and classify the SVT as the AF if the change is more than the threshold.

19. The system of claim 17, wherein the controller is configured to determine if a percent change in the ventricular rate regularity is more than a percent change threshold.

20. The system of claim 13, wherein the controller is configured to determine a similarity value (S_PRE) of a ventricular morphology before delivering the diagnostic neural stimulation to a normal sinus rhythm (NSR) template, determine a similarity value (S_POST) of a ventricular morphology during delivering the diagnostic neural stimulation to the NSR template, and use the S_PRE and the S_POST to classify the arrhythmia as either the SVT or the VT.

21. The system of claim 20, wherein the controller is configured to classify the arrhythmia as the SVT if S_POST is greater than a first threshold (TH₁), or if the S_POST is greater than a second threshold (TH₂) and the difference between S_POST and S_PRE is greater than a third threshold (TH₃).

22. The system of claim 13, further comprising sensors configured to sense ventricular hemodynamics, wherein the controller is configured to use ventricular hemodynamics (V HEMO_PRE) before delivering the diagnostic neural stimulation and ventricular hemodynamics (V HEMO_POST) while delivering the diagnostic neural stimulation to classify the arrhythmia as either the SVT or the VT.