Implantable myocardial ischemia detection, indication and action technology

• US 7,277,745 B2
• Filed: 09/15/2002
• Issued: 10/02/2007
• Est. Priority Date: 08/07/1998
• Status: Expired due to Fees

• Current Assignee: Infinite Biomedical Technologies, LLC
• Original Assignee: Infinite Biomedical Technologies, LLC
• Inventors: Thakor, Nitish V., Natarajan, Ananth
• Primary Examiner(s): Getzow; Scott M.
• Application Number:
  US10/243,701
• Publication Number:
  US 20030013974A1
• Time in Patent Office: 1,843 Days
• Field of Search: 607 3- 28, 600508-510
• US Class Current: 600/509
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• 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: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy

Abstract

One embodiment enables detection of MI/I and emerging infarction in an implantable system. A plurality of devices may be used to gather and interpret data from within the heart, from the heart surface, and/or from the thoracic cavity. The apparatus may further alert the patient and/or communicate the condition to an external device or medical caregiver. Additionally, the implanted apparatus may initiate therapy of MI/I and emerging infarction.

Claims

1. A method for monitoring electrogram signals in a subject, comprising:

acquiring electrogram signals within the subject by positioning a plurality of sensors transveneously within the subject, the electrogram signals including a depolariztion wave region and a repolarization wave region, the sensors electrically coupled to an implanted device including electronics therein;

analyzing the depolarization wave region of the electrogram signals using the implanted device to obtain information relating to changes in the depolarization wave region; and

determining whether MI/I has occurred, using the information relating to changes in the depolarization wave region.

2. A method as in claim 1, further comprising analyzing the repolarization wave region of the electrogram signals using the implanted device to obtain additional information relating to changes in the repolarization wave region, and wherein the determining whether MI/I has occurred also includes using the additional information related to changes in the repolarization wave region.

3. A method for monitoring electrogram signals in a subject, comprising:

acquiring electrogram signals from the subject'"'"'s heart, the electrogram signals including a depolariztion wave region and a repolarization wave region;

analyzing the depolarization wave region of the electrogram signals using electronics positioned within the subject, wherein the analyzing includes obtaining depolarization information relating to changes in the depolarization wave region due to MI/I;

analyzing the repolarization wave region of the electrogram signals using the electronics positioned within the subject, wherein the analyzing includes obtaining repolarization information relating to changes in the repolarization wave region due to MI/I; and

determining, in the subject, whether MI/I has occurred, using the depolarization information and the repolarization information.

4. A method of detecting myocardial ischemia in a subject, comprising analyzing an electrogram signal by determining its temporal features synchronous to the Q, R, S, and T waves in a surface ECG signal, wherein determining its temporal features synchronous to the Q, R, S, and T waves includes providing a plurality of sensors adapted to deliver signals to a device implanted in the subject, storing an electrogram signal from each lead into a digital memory in the device, and comparing an acquired electrogram signal to the stored electrogram signal.

5. A method as in claim 4, wherein the analyzing includes:

identifying changes in the morphology of depolarization upstroke synchronous with the Q and R waves;

identifying changes in the morphology of depolarization downstroke synchronous with the R and S waves; and

identifying changes in the morphology of repolarization synchronous with the S and T waves.

6. A method as in claim 5, further comprising obtaining the electrogram signal from at least one lead positioned in a location selected from the group consisting of endocardial, epicardial, thoracic cavity, subpectorial and subcutaneous.

7. A method as in claim 6, wherein the analyzing comprises analyzing a unipolar electrogram signal.

8. A method as in claim 6, wherein the analyzing comprises analyzing a bipolar electrogram signal.

9. A method for distinguishing normal and ischemic signal information comprising:

analyzing signals derived from a plurality of sensors implanted transveneously in a subject, the sensors adapted to obtain signals comprising a waveform of at least one heartbeat, the waveform including a depolarization region and a repolarization region;

wherein the analyzing signals comprises analyzing the waveform using at least one method selected from the group consisting of a temporal domain method and a frequency domain method,

wherein the temporal domain method comprises determining a magnitude of a signal power over the depolarization region and repolarization region of at least one heartbeat; and

wherein the frequency domain method comprises performing a spectral analysis of a frequency component of the waveform over the depolarization region and the repolarization region of at least one heartbeat.

10. A method as in claim 9, wherein the plurality of sensors are selected from one or more of the group consisting of pressure sensors, volume sensors, conductance sensors, impedance sensors, pH sensors, pO₂ sensors, temperature sensors, and blood-based biochemical sensors.

11. A method as in claim 9, wherein the analyzing signals comprises analyzing the waveform using a temporal domain method.

12. A method as in claim 9, wherein the analyzing signals comprises analyzing the waveform using a frequency domain method.

13. A method as in claim 9, wherein the analyzing signals comprises analyzing the waveform using a temporal domain method and a frequency domain method.

14. A method for monitoring a subject for MI/I, wherein a pacemaker is connected to the subject'"'"'s heart, the method comprising:

acquiring a paced electrogram signal within the subject, the paced electrogram signal including a depolarization wave region and a repolarization wave region;

obtaining information relating to changes in the depolarization wave region over a plurality of heartbeats;

obtaining additional information relating to changes in the repolarization wave region over a plurality of heartbeats; and

analyzing the information relating to changes in the depolarization wave region and the additional information relating to changes in the repolarization wave region using electronics positioned in the subject and determining whether MI/I has occurred.

15. A method for treating a subject comprising:

implanting a device in the subject;

acquiring electrogram signals within the subject using the device, the electrogram signals including a depolariztion wave region and a repolarization wave region;

determining whether MI/I has occurred in the subject using the device in the subject, wherein the determining whether MI/I has occurred includes one of;

(i) analyzing the depolarization wave region of the electrogram signals, wherein the analyzing includes obtaining depolarization information relating to changes in the depolarization wave region due to MI/I, or (ii) analyzing the depolarization wave region and the repolarization wave region of the electrogram signals, wherein the analyzing includes obtaining depolarization and repolarization information relating to changes in the depolarization and repolarization wave regions;

generating a therapy signal in the device when a determination that MI/I has occurred is made; and

initiating a therapy in the subject based on the therapy signal generated by the device.

16. A method as in claim 15, wherein the therapy comprises delivering at least one drug selected from the group consisting of bicarbonate, epinephrine, heparin, TPA, streptokinase, and beta blockers.

17. A method as in claim 15, wherein the at least one drug comprises an anti-arrhythmic drug.

18. A method as in claim 15, wherein the device includes at least one drug embedded in a polymer matrix and initiating therapy includes the release of the drug through the polymer matrix.

19. A method as in claim 15, wherein the device includes at least one drug embedded in a portion of the device selected from a lead, a catheter and tubing, and initiating therapy includes releasing a drug from the portion of the device.

20. A method as in claim 15, wherein initiating the therapy includes delivering an electrical shock to the subject.

21. A method as in claim 20, wherein the device includes a plurality of leads and positioning the leads at one or more positions selected from the group of intracavitary, epicardial, thoracic, and subcutaneous positions in the subject and therapy includes delivering a shock to the subject through at least one of the leads.

22. A method as in claim 15, wherein the therapy is initiated immediately after detecting MI/I.

23. A method as in claim 15, wherein the therapy includes treatment that can be carried out by the implanted device.

24. A method as in claim 23, wherein the treatment that can be carried out by the implanted device is initiated immediately after detecting MI/I.

25. A method as in claim 23, wherein the treatment that can be carried out by the implanted device is initiated within one hour after detecting MI/I.

26. A method as in claim 15, wherein detecting MI/I comprises detecting MI/I selected from the group consisting of transient MI/I, permanent MI/I, and recurrent MI/I.

27. A method as in claim 15, wherein detecting MI/I comprises detecting MI/I following an event selected from the group consisting of cardiac arrest, cardioversion, and defibrillation.

28. A method as in claim 15, wherein detecting MI/I comprises detecting MI/I following an event selected from the group consisting of drug infusion and angioplasty therapy.

29. A method as in claim 15, wherein detecting MI/I comprises detecting MI/I in the presence of an event selected from the group of arrhythmia and normal sinus rhythm.

30. A method as in claim 15, further comprising generating an alarm signal when a determination that MI/I has occurred is made, and transmitting the alarm signal to a position external to the device.

31. An apparatus for determining the location of a MI/I event in a subject, comprising an implantable device including a plurality of sensors adapted to be positioned in and around the heart, the device further including means for analyzing the changes in electrogram signals received from the sensors and means for determining the location using dipole projection.