Discriminating between tachycardias of ventricular origin and supra-ventricular origin, methods and apparatus

• US 8,195,281 B2
• Filed: 03/27/2009
• Issued: 06/05/2012
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Sorin CRM USA (MicroPort Scientific Corp.)
• Original Assignee: Sorin CRM USA (MicroPort Scientific Corp.)
• Inventors: Dal Molin, Renzo, Henry, Christine, Bouchet, Paola, El Arab, Jinan, Dubois, Rémi, Dreyfus, Gérard
• Primary Examiner(s): Lavert, Nicole F
• Application Number:
  US12/412,808
• Publication Number:
  US 20100249626A1
• Time in Patent Office: 1,166 Days
• Field of Search: 600/515, 600/518, 607/4, 607/26
• US Class Current: 600/518
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: G06F 2218/18 by plotting the signal segments against each other, e.g. analysing scattergrams
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

An active medical device able to discriminate between tachycardias of ventricular origin and of supra-ventricular origin. Two distinct temporal components (UnipV, BipV) are obtained corresponding to two EGM signals of ventricular electrograms. The diagnosis operates in at least two-dimensional space to determine, from the variations of one temporal component as a function of the other temporal component, a 2D characteristic representative of a heart beat and, this, for a reference beat collected in Sinus Rhythm (SR) in the absence of tachycardia episodes, and for a heart beat in Tachycardia. The discrimination of the tachycardia type, VT or SVT, is then realized by a classifier operating a comparison of the two current and reference 2D characteristics.

Claims

1. An active medical device comprising:

a. a means for collecting an electrical activity of a patient'"'"'s heart, including a means for producing at least two distinct temporal components corresponding to two distinct EGM signals of a ventricular electrogram;

the collecting means further comprising means for producing a first and a second distinct temporal components from said two distinct EGM signals of ventricular electrogram;

b. a means for detecting a presence of a tachycardia episode the two distinct EGM signals of a ventricular electrogram; and

c. a diagnosis means for diagnosing a ventricular tachyarrhythmia including means for discriminating in the detected tachycardias between a Ventricular Tachycardia and a Supra-Ventricular Tachycardia

the diagnosis means further comprising;

i. a means for conducting a bi-dimensional analysis, able to determine, from a variation of one of said first and second temporal components as a function of the other of said first and second temporal components, a 2D characteristic representative of a heart beat; and

ii. discriminator means further comprising means for comparing;

1. a first current 2D characteristic, representative of a tachycardia beat wherein the two EGM signals collected are during a tachycardia episode, and

2. a second reference 2D characteristic, representative of a Sinus Rhythm beat wherein the two EGM signals are collected from non-tachycardia episodes.

2. The device of claim 1, wherein the EGM signals include a QRS complex and the means for conducting the bi-dimensional analysis further comprises a temporal window (W_QRS) including a QRS complex of said heart beat and means for determining said 2D characteristic based on said temporal components occurring during said window.

3. The device of claim 1, wherein the diagnosis means further comprises means for determining said reference 2D characteristic from a plurality of averaged successive heart beats.

4. The device of claim 3, wherein the diagnosis means further comprises means for detecting not representative beats in said plurality of heart beats, and excluding said not representative beats from the determination of the reference 2D characteristic.

5. The device of claim 4, wherein the means for detecting the non-representative heart beats further comprises means for performing a morphological analysis of said plurality of heart beats by a cross-correlation.

6. The device of claim 5, wherein the means for performing a morphological analysis further comprises means for identifying by clustering of non-representative beats.

7. The device of claim 1, wherein the discriminator means further comprises means for characterizing said current and reference 2D characteristics by at least one geometrical descriptor ({right arrow over (e)}_T, c), and comparing said current and reference 2D characteristics by the determined geometrical descriptor.

8. The device of claim 7, wherein the geometrical descriptor further comprises a unit tangent vector ({right arrow over (e)}_T) to the 2D characteristic, considered at a plurality of points.

9. The device of claim 8, wherein the discriminator means further comprises means for evaluating an average angle between unit tangent vectors to respectively the current 2D characteristic and the reference 2D characteristic.

10. The device of claim 7, wherein said geometrical descriptor further comprises a norm of the velocity vector of the 2D characteristic, considered in a plurality of points.

11. The device of claim 10, wherein the discriminator means further comprises means for evaluating a correlation coefficient between the norms of the velocity vectors of respectively the current 2D characteristic and the reference 2D characteristic.

12. The device of claim 7, wherein said geometrical descriptor further comprises the curvature (c) of the 2D characteristic, considered in a plurality of points.

13. The device of claim 12, wherein the discriminator means further comprises means for evaluating a correlation coefficient between the curvature (c) of the 2D characteristic and the reference 2D characteristic.

14. The device of claim 1, wherein the bi-dimensional analysis means further comprises means for determining a reference mark orthonormal to an axis corresponding to a main axis of the patient'"'"'s heart.

15. The device of claim 14, wherein means for determining said reference mark further comprises means for analyzing a sinus EGM signal wherein the EGM signal is collected in the absence of tachycardia episodes.

16. The device of claim 14, further comprising means for applying to said first and second 2D characteristics a reference change, from a primitive reference to said reference mark.

17. The device of claim 16, wherein said diagnosis means further comprises means for analyzing said main axis components and producing a first descriptor parameters of a morphology of said first and second 2D characteristics.

18. The device of claim 17, wherein said first descriptor parameters are parameters selected from the group consisting of:

first and second eigen values of a covariance matrix associated to each of these eigen values;

orientation of the main axis of the patient'"'"'s heart and a secondary axis;

a ratio between an extreme signal amplitudes on at least two channels; and

an area circumscribed by the 2D characteristic.

19. The device of claim 14, wherein said diagnosis means further comprises means for producing a first and a second one-dimensional component by projection of each of said first and second 2D characteristic on one of the axis of said reference mark.

20. The device of claim 19, wherein said diagnosis means further comprises means for producing second descriptor parameters of the morphology of said first and second one-dimensional component.

21. The device of claim 20, wherein said second descriptor parameters are parameters selected from the group consisting of:

a signal maximum height;

a signal minimum height; and

a signal width.

22. The device of claim 14, wherein said diagnosis means further comprises means for providing an inter-correlation between said first and second 2D characteristics.

23. The device of claim 1, wherein the bi-dimensional analysis means further comprises:

means for determining a reference mark orthonormal to an axis corresponding to a main axis of the patient'"'"'s heart;

means for applying to said first and second 2D characteristics a reference change, from a primitive reference to said reference mark;

means for analyzing said main axis components and producing a first descriptor parameters of a morphology of said first and second 2D characteristics,

wherein said first descriptor parameters are first and second eigen values of a covariance matrix associated to each of these eigen values; and

means for providing an inter-correlation between said first and second 2D characteristics, wherein said inter-correlation means further comprises means for providing a bi-dimensional distribution analysis between the correlation coefficients and the eigen values of the covariance matrix of an analysis in principal components.

24. The device of claim 23, wherein said inter-correlation means further comprises means for providing a three-dimensional distribution analysis, able to define, for at least one descriptor parameter of the morphology of said first and second 2D characteristics, a discriminator plane between ventricular originated tachycardias and supra-ventricular originated tachycardias.

25. The device of claim 24, wherein said inter-correlation means further comprises a linear classifier means for performing said three-dimensional distribution analysis.

26. The device of claim 24, wherein said three-dimensional distribution analysis means further comprises an adaptive neural network classifier.

27. The device of claim 14, wherein diagnosis means are essentially devoid of an analysis in principle components.

28. The device of claim 27, wherein said diagnosis means further comprises means for determining ratios between a maximum amplitude and a minimum amplitude of a depolarization complex for each of said two distinct temporal components, respectively for said Sinus Rhythm and tachycardia beats.

29. The device of claim 27, wherein said diagnosis means further comprises means for determining a correlation maximum between said 2D characteristics from said Sinus Rhythm and Tachycardia beats.