Method and apparatus for monitoring arrythmogenic effects of medications using an implantable device

• US 8,934,963 B1
• Filed: 01/16/2007
• Issued: 01/13/2015
• Est. Priority Date: 01/16/2007
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Farazi, Taraneh Ghaffari
• Primary Examiner(s): Heller, Tammie K
• Application Number:
  US11/623,613
• Time in Patent Office: 2,919 Days
• Field of Search: 600/510, 600515-517
• US Class Current: 600/516
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61N 1/0563 specially adapted for defibrillation or cardioversion
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/36507 controlled by gradient or slope of the heart potential
• CPC Class Codes: A61N 1/36592 controlled by the heart rate variability
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators

Abstract

An implantable device and method for monitoring changes in the risk of arrhythmia induced by medications. The implantable device monitors risk of arrhythmia by analyzing an aspect of T-wave morphology to generate a metric of transmural dispersion of repolarization (“TDR”) as a proxy for the risk of arrhythmia. The implantable device generates an index of change in the risk of arrhythmia by comparing values of the metric of TDR obtained for different time periods. The implantable device generates a warning if the change in risk of arrhythmia is outside acceptable limits. The implantable device can also communicate with other devices to correlate changes in risk of arrhythmia with medications taken by the patient.

Claims

1. In an implantable system, a method for monitoring for an increase in arrhythmic vulnerability following administration of a medication other than an antiarrhythmic medication, comprising:

(a) during a first time period, substantially coincident with commencing the administration of the medication other than an antiarrhythmic medication, obtaining an electrogram (EGM) signal from a patient via the implantable system, and analyzing one or more attributes of T-waves of the EGM signal to generate a first metric representative of transmural dispersion of repolarization (TDR);

(b) during a second time period, following the administration of the medication other than an antiarrhythmic medication, obtaining a further EGM signal from the patient via the implantable system, and analyzing one or more attributes of T-waves of the further EGM signal to generate a further metric representative of TDR;

(c) determining an index indicative of a total increase in arrhythmic vulnerability and an index indicative of a rate of increase in arrhythmic vulnerability following the administration of the medication other than an antiarrhythmic medication by comparing the further metric representative of TDR to the first metric representative of TDR; and

(d) triggering an alert signal if at least one of the index indicative of the total increase in arrhythmic vulnerability or the index indicative of the rate of increase in arrhythmic vulnerability is outside of acceptable bounds defined by one or more thresholds;

wherein steps (a), (b) and (c) are performed by the implantable system; and

wherein the one or more attributes of T-waves analyzed at steps (a) and (b) is/are the same and comprise(s) at least one of an interval from an apex to an end of T-waves, a peak amplitude of T-waves, a slope of T-waves, an area under the curve of T-waves, a morphology of T-waves, or a complexity of T-waves.

2. The method of claim 1, wherein:

step (a) includes storing, within a memory of the implantable system, the first metric representative of TDR generated for the first time period; and

step (b) includes storing, within the memory of the implantable system, the further metric representative of TDR for the second time period.

3. The method of claim 2, wherein the first time period is triggered in response to a start signal received from outside of the patient.

4. The method of claim 3, wherein the start signal is received in association with administration of the medication other than an antiarrhythmic medication to the patient.

5. The method of claim 1, further comprising:

(e) automatically adjusting delivery of the medication other than an antiarrhythmic medication by a medication pump in response to a change from the first metric representative of TDR to the further metric representative of TDR.

6. The method of claim 1, further comprising:

(e) recording data regarding medication administered to the patient; and

(f) comparing changes in arrhythmic vulnerability to the data regarding medication administered to the patient.

7. The method of claim 6, further comprising:

(g) communicating the changes in arrhythmic vulnerability to an external system wherein the external system correlates said changes in arrhythmic vulnerability to the administration of the medication and suggests a change in the administration of the medication.

8. The method of claim 1, wherein the one or more attributes of T-waves comprises a complexity of the T-waves.

9. The method of claim 1, wherein the one or more attributes of T-waves comprises an interval from an apex to an end of the T-waves.

10. The method of claim 1, wherein the one or more attributes of T-waves comprises an area under the curve of T-waves.

11. A system for implantation in a patient, comprising:

a plurality of implantable electrodes configured to produce an electrogram (EGM) signal; and

a controller configured to;

analyze one or more attributes of T-waves of an EGM signal obtained during a first time period, substantially coincident with administration of a medication other than an antiarrhythmic medication, to generate a first metric representative of transmural dispersion of repolarization (TDR);

analyze one or more attributes of T-waves of an EGM signal obtained during a second time period, following the administration of the medication other than an antiarrhythmic medication, to generate a further metric representative of TDR;

determine an index indicative of a total increase in arrhythmic vulnerability and an index indicative of a rate of change in arrhythmic vulnerability following administration of the medication other than an antiarrhythmic medication by comparing the further metric representative of TDR to the first metric representative of TDR; and

trigger an alert signal if at least one of the index indicative of the total increase in arrhythmic vulnerability or the index indicative of the rate of increase in arrhythmic vulnerability is outside of acceptable bounds defined by one or more thresholds;

wherein the one or more attributes of T-waves obtained during the first and second time periods is/are the same and comprise(s) at least one of an interval from an apex to an end of T-waves, a peak amplitude of T-waves, a slope of T-waves, an area under the curve of T-waves, a morphology of T-waves, or a complexity of T-waves.

12. The system of claim 11, further comprising:

a memory configured to store the first metric of TDR generated for the first time period and the further metric of TDR generated for the second time period.

13. The system of claim 12, further comprising:

a receiver circuit configured to receive a start signal from outside the patient;

wherein the first time period is triggered in response to the start signal.

14. The system of claim 11, further comprising:

a medication pump controller configured to adjust delivery of the medication other than an antiarrhythmic medication in response to changes in the metric representative of TDR.

15. The system of claim 11, wherein the one or more attributes of T-waves comprises a complexity of the T-waves.

16. The system of claim 11, wherein the one or more attributes of T-waves comprises an interval from an apex to an end of the T-waves.

17. The system of claim 11, wherein the one or more attributes of T-waves comprises an area under the curve of T-waves.