System and Method for Distinguishing Between Hypoglycemia and Hyperglycemia Using an Implantable Medical Device

• US 20090177103A1
• Filed: 03/18/2009
• Published: 07/09/2009
• 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 8,078,271 B2
• Time in Patent Office: Days
• US Class Current: 600/516
• 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 detecting one of hypoglycemia and hyperglycemia within a patient in which the device is implanted, said method comprising:

tracking with the implantable medical device, rates of change of at least one of atrial depolarization amplitudes, ventricular depolarization amplitudes and ventricular repolarization amplitudes;

detecting with the implantable medical device, an onset of hyperglycemia upon detecting a rapid increase in at least one of the rate of change of atrial depolarization amplitudes and ventricular depolarization amplitudes; and

detecting with the implantable medical device, an onset of hypoglycemia upon detecting a rapid increase in the rate of change of ventricular repolarization amplitudes.

2. The method of claim 1 wherein detecting a rapid increase in at least one of the rate of change of atrial depolarization amplitudes and ventricular depolarization amplitudes comprises:

calculating a rate of change for at least one of atrial depolarization amplitudes and ventricular depolarization amplitudes;

comparing the calculated rate of change with a predetermined threshold rate of change indicative of the onset of hyperglycemia; and

detecting hyperglycemia when the calculated rate of change exceeds the predetermined threshold rate of change.

3. The method of claim 2 wherein the calculated rate of change is calculated over a period of time.

4. The method of claim 2 wherein the calculated rate of change is calculated on a beat by beat basis.

5. The method of claim 1 wherein detecting a rapid increase in the rate of change of ventricular repolarization amplitudes comprises:

calculating a rate of change for ventricular repolarization amplitudes;

comparing the calculated rate of change with a predetermined threshold rate of change indicative of the onset of hypoglycemia; and

detecting hypoglycemia when the calculated rate of change exceeds the predetermined threshold rate of change.

6. The method of claim 5 wherein the calculated rate of change is calculated over a period of time.

7. The method of claim 5 wherein the calculated rate of change is calculated on a beat by beat basis.

8. The method of claim 1 further comprising, upon detecting an onset of hyperglycemia, confirming hyperglycemia by:

calculating a rate of change for ventricular repolarizations; and

determining that the rate of change corresponds to a lack of significant change in ventricular repolarization amplitudes.

9. The method of claim 1 further comprising, upon detecting an onset of hypoglycemia, confirming hypoglycemia by:

calculating a rate of change for atrial depolarizations; and

determining that the rate of change corresponds to a lack of significant change in atrial depolarization amplitudes.

10. An implantable medical device comprising:

a detector operative to detect at least one of atrial depolarization amplitudes, ventricular depolarization amplitudes and ventricular repolarization amplitudes; and

a processor operative to;

track rates of change of at least one of atrial depolarization amplitudes, ventricular depolarization amplitudes and ventricular repolarization amplitudes;

detect an onset of hyperglycemia upon detecting a rapid increase in at least one of the rate of change of atrial depolarization amplitudes and ventricular depolarization amplitudes; and

detect an onset of hypoglycemia upon detecting a rapid increase in the rate of change of ventricular repolarization amplitudes.

11. An implantable medical device comprising:

a detector operative to detect at least one of atrial depolarization amplitudes, ventricular depolarization amplitudes and ventricular repolarization amplitudes; and

a processor operative to;

track amplitude-based parameters within electrical cardiac signals over time corresponding to amplitudes of atrial depolarizations, ventricular depolarizations and ventricular repolarizations;

detect hyperglycemia upon detection of an increase in atrial depolarization amplitudes, an increase in ventricular depolarization amplitudes and a lack of significant change in ventricular repolarization amplitudes; and

detect hypoglycemia upon detection of a lack of significant change in atrial depolarization amplitudes, an increase in ventricular depolarization amplitudes and an increase in ventricular repolarization amplitudes.