System and method for distinguishing between hypoglycemia and hyperglycemia using an implantable medical device

• US 20060167365A1
• Filed: 05/11/2005
• Published: 07/27/2006
• Est. Priority Date: 01/25/2005
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Bharmi, Rupinder
• Granted Patent: US 7,524,287 B2
• Time in Patent Office: Days
• US Class Current: 600/517
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/358 Detecting ST segments
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• 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 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

Techniques are described for detecting and distinguishing among ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. In one technique, these conditions are detected and distinguished based on an analysis of: the interval between the QRS complex and the peak of a T-wave (QTmax), the interval between the QRS complex and the end of a T-wave (QTend), alone or in combination with a change in ST segment elevation. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by cardiac ischemia. In another technique, hyperglycemia and hypoglycemia are predicted, detected and/or distinguished from one another based on an analysis of the amplitudes of P-waves, QRS-complexes and T-waves within the IEGM. Appropriate warning signals are delivered and therapy is automatically adjusted.

Claims

1. A method for use with an implantable medical device for distinguishing between hypoglycemia and hyperglycemia within a patient in which the device is implanted, the method comprising:

detecting an amplitude-based parameter representative of an amplitude of one or more selected electrical events of the heart; and

distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter.

2. The method of claim 1 wherein detecting an amplitude-based parameter representative of amplitudes of electrical events sensed within the heart of the patient is performed in response to one or more of:

atrial depolarization events, ventricular depolarization events, and ventricular repolarization events.

3. The method of claim 1 wherein detecting an amplitude-based parameter representative of amplitudes of electrical events sensed within the heart of the patient is performed in to detect one or more of:

the absolute values of the amplitudes of the electrical events;

a rate of change in the amplitudes of the electrical events over time;

or a rate of change in the amplitudes of the electrical events over time.

4. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect absolute values of the amplitudes of atrial depolarization events;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based is performed to associate a significant increase in the absolute value of the amplitudes of the atrial depolarization events with hyperglycemia.

5. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a rate of change in the amplitudes of atrial depolarization events over time;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate a significant rate of change in the amplitudes of the atrial depolarization events over time with hyperglycemia.

6. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a change in the amplitudes of atrial depolarization events from beat to beat;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate a significant change in the amplitudes of the atrial depolarization events from beat to beat with hyperglycemia.

7. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect absolute values of the amplitudes of ventricular depolarization events;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based is performed to associate a more significant increase in the absolute value of the amplitudes of the ventricular depolarization events with hyperglycemia than with hypoglycemia.

8. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a rate of change in the amplitudes of ventricular depolarization events over time;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate a faster rate of change in the amplitudes of the ventricular depolarization events over time with hyperglycemia than with hypoglycemia.

9. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a change in the amplitudes of ventricular depolarization events from beat to beat;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate faster rate of change in the amplitudes of the ventricular depolarization events from beat to beat with hyperglycemia than with hypoglycemia.

10. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect absolute values of the amplitudes of ventricular repolarization events;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based is performed to associate a significant increase in the absolute value of the amplitudes of the ventricular repolarization events with hypoglycemia.

11. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a rate of change in the amplitudes of ventricular repolarization events over time;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate a significant rate of change in the amplitudes of the atrial depolarization events over time with hypoglycemia.

12. The method of claim 1

wherein detecting the amplitude-based parameter is performed to detect a change in the amplitudes of ventricular repolarization events from beat to beat;

and

wherein distinguishing hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter is performed to associate a significant change in the amplitudes of the ventricular repolarization events from beat to beat with hypoglycemia.

13. The method of claim 1 further comprising controlling therapy based on whether the patient is subject to hypoglycemia or hyperglycemia.

14. The method of claim 13 wherein an implantable drug pump is provided for delivering insulin and wherein, if the patient is subject to hypoglycemia, controlling therapy comprises reducing insulin delivery to the patient using the insulin pump.

15. The method of claim 13 wherein an implantable insulin pump is provided and wherein, if the patient is subject to hyperglycemia, controlling therapy comprises increasing insulin delivery to the patient using the insulin pump.

16. The method of claim 1 further comprising generating a warning signal.

17. The method of claim 1 wherein the implantable device include a defibrillator with defibrillation shock capacitors and wherein, if the patient is subject to hypoglycemia, the method further comprises charging the capacitors.

18. The method of claim 1 further comprising recording diagnostic information based on whether the patient is subject to hypoglycemia or hyperglycemia.

19. The method of claim 18 further comprising examining the recorded diagnostic information to predict episodes of hypoglycemia or hyperglycemia.

20. The method of claim 19 wherein examining the recorded diagnostic information to predict episodes of hypoglycemia or hyperglycemia is performed by identifying a trend in the amplitude-based parameter.

21. The method of claim 20 further comprising issuing a warning signal upon prediction of an episode of hypoglycemia or hyperglycemia.

22. An implantable medical device for distinguishing between hypoglycemia and hyperglycemia, comprising:

an electrical event detector operative to detect an amplitude-based parameter representative of amplitudes of one or more selected electrical events of the heart; and

a hypoglycemia/hyperglycemia distinguishing unit operative to distinguish hypoglycemia and hyperglycemia from one another based on the amplitude-based parameter.

23. A system for use with an implantable medical device for distinguishing between hypoglycemia and hyperglycemia within a patient in which the device is implanted, comprising:

means for detecting an amplitude-based parameter of one or more selected electrical events of the heart; and

means for distinguishing hypoglycemia from hyperglycemia based on the amplitude-based parameter.