METHOD, APPARATUS AND COMPUTER PROGRAM PRODUCT FOR PREDICTING VENTRICULAR TACHYARRHYTHMIAS

• US 20130261479A1
• Filed: 03/30/2012
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Kaski, Mikko, Kemppainen, Reko
• Granted Patent: US 8,838,224 B2
• Time in Patent Office: Days
• US Class Current: 600/517
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/355 Detecting T-waves
• 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: G16H 40/60 for the operation of medical equipment or devices
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A method, apparatus, and computer program product for predicting ventricular tachyarrhythmia (VTA) are disclosed. To provide a mechanism that allows prediction of VTA events efficiently within a few hours before the onset of the actual event, a set of repolarization parameters indicative of ventricular repolarization in a subject'"'"'s heart is determined in successive time segments, thereby to obtain a time series of the set of repolarization parameters. Based on the time series, at least one change indication variable indicative of changes in the ventricular repolarization of the heart is produced and the risk of potential ventricular tachyarrhythmia is predicted based on the at least one change indication variable.

Claims

1. A method for predicting ventricular tachyarrhythmia, the method comprising:

determining a set of repolarization parameters indicative of ventricular repolarization in a subject'"'"'s heart, wherein the determining is performed in successive time segments, thereby to obtain a time series of the set of repolarization parameters;

producing, based on the time series, at least one change indication variable indicative of changes in the ventricular repolarization of the heart; and

predicting risk of potential ventricular tachyarrhythmia based on the at least one change indication variable.

2. The method according to claim 1, wherein the producing comprises producing the at least one change indication variable, in which the at least one change indication parameter comprises a trend variable indicative of slow changes in the ventricular repolarization of the heart and at least one fast change variable indicative of fast changes in the ventricular repolarization of the heart.

3. The method according to claim 2, wherein the producing comprises

producing the trend variable, in which the trend variable represents a weighted average of a plurality of repolarization parameters, wherein the plurality of repolarization parameters belong to the set of repolarization parameters;

estimating a relationship between a repolarization parameter and heart rate, wherein the repolarization parameter belongs to the set of repolarization parameters and wherein the estimating is performed for at least one repolarization parameter, thereby to obtain at least one relationship; and

producing the at least one fast change variable, in which the at least one fast change variable comprises a first variable indicative of similarity between successive sets of repolarization parameters in the time series and a second variable indicative of change in difference between a first and a second group of repolarization parameters, wherein the first group is obtained through the at least one relationship and the second group belongs to the time series.

4. The method according to claim 3, wherein the producing comprises producing the first variable and a second variable, in which the first variable represents Mahalanobis distance between selected repolarization parameters obtained in successive sets of the time series and the second variable represents ratio of two differences obtained through the at least one relationship in successive time segments, wherein each difference represents difference between repolarization parameters estimated through the at least one relationship and respective repolarization parameters obtained in the time series.

5. The method according to claim 3, wherein the predicting comprises

comparing the trend variable with a predetermined threshold;

and

detecting increased risk of ventricular tachyarrhythmia when the trend variable reaches the predetermined threshold.

6. The method according to claim 2, wherein the predicting comprises determining at least one control parameter indicative of occurrences of events that affect the ventricular repolarization of the heart without increasing risk of ventricular tachyarrhythmia.

7. The method according to claim 6, wherein the predicting comprises discarding at least one of detected fast changes and detected slow changes, in which the discarding is performed conditionally based on the at least one control parameter.

8. The method according to claim 1, wherein the determining comprises determining the set of repolarization parameters, in which the set comprises morphology parameters indicative of T wave morphology.

9. The method according to claim 8, wherein the determining comprises determining the set of repolarization parameters, in which the set comprises T wave amplitude, T wave asymmetry, T wave area, ST level, and ST slope.

17. The method according to claim 1, wherein the set of repolarization parameters comprises morphology parameters indicative of T wave morphology.

18. The method according to claim 17, wherein the set of repolarization parameters comprises T wave amplitude, T wave asymmetry, T wave area, ST level, and ST slope.

10. An apparatus for predicting ventricular tachyarrhythmia, the apparatus comprising:

a first parameter unit adapted to determine a set of repolarization parameters indicative of ventricular repolarization in a subject'"'"'s heart, wherein the first parameter unit is adapted to determine the repolarization parameters in successive time segments, thereby to obtain a time series of the set of repolarization parameters;

a change indicator unit adapted to produce, based on the time series, at least one change indication variable indicative of changes in the ventricular repolarization of the heart; and

a risk evaluation unit adapted to predict risk of potential ventricular tachyarrhythmia based on the at least one change indication variable.

11. The apparatus according to claim 10, wherein the at least one change indication variable comprises a trend variable indicative of slow changes in the ventricular repolarization of the heart and at least one fast change variable indicative of fast changes in the ventricular repolarization of the heart.

12. The apparatus according to claim 11, wherein

the trend variable represents a weighted average of a plurality of repolarization parameters, wherein the plurality of repolarization parameters belong to the set of repolarization parameters;

the apparatus is adapted to estimate a relationship between a repolarization parameter and heart rate, wherein the repolarization parameter belongs to the set of repolarization parameters, and wherein the apparatus is adapted to estimate the relationship for at least one repolarization parameter, thereby to obtain at least one relationship; and

the at least one fast change variable comprises a first variable indicative of similarity between successive sets of repolarization parameters in the time series and a second variable indicative of change in difference between a first and a second group of repolarization parameters, wherein the first set is obtained through the at least one relationship and the second set belongs to the time series.

13. The apparatus according to claim 12, wherein the first variable represents Mahalanobis distance between selected repolarization parameters obtained in successive sets of the time series and the second variable ratio of two differences obtained through the at least one relationship in successive time segments, and wherein each difference represents difference between repolarization parameters estimated through the at least one relationship and respective repolarization parameters obtained in the time series.

14. The apparatus according to claim 12, wherein the risk evaluation unit is adapted to

compare the trend variable with a predetermined threshold;

and

detect increased risk of ventricular tachyarrhythmia when the trend variable reaches the predetermined threshold.

15. The apparatus according to claim 10, further comprising a second parameter unit adapted to determine at least one control parameter indicative of occurrences of events that affect the ventricular repolarization of the heart without increasing risk of ventricular tachyarrhythmia.

16. The apparatus according to claim 15, wherein the risk evaluation unit is adapted to discard, conditionally based on the at least one control parameter, at least one of detected fast changes and detected slow changes.

19. A computer program product for predicting ventricular tachyarrhythmia, the computer program product comprising:

a first program product portion adapted to determine a set of repolarization parameters indicative of ventricular repolarization in a subject'"'"'s heart, wherein the first program product portion is adapted to determine the repolarization parameters in successive time segments, thereby to obtain a time series of the set of repolarization parameters;

a second program product portion adapted to produce, based on the time series, at least one change indication variable indicative of changes in the ventricular repolarization of the heart; and

a third program product portion adapted to evaluate risk of potential ventricular tachyarrhythmia based on the at least one change indication variable.