Implantable device that diagnoses ischemia and myocardial infarction and method

• US 7,181,269 B1
• Filed: 04/12/2004
• Issued: 02/20/2007
• Est. Priority Date: 04/12/2004
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Kroll, Mark W.
• Primary Examiner(s): Pezzuto; Robert E.
• Assistant Examiner(s): Heller; Tammie K.
• Application Number:
  US10/823,427
• Time in Patent Office: 1,044 Days
• Field of Search: 600/481, 600/483, 600/515, 600/517, 607/18, 607/25, 607/26
• US Class Current: 600/517
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

An implantable device detects and discriminates between ischemia and myocardial infarction. The device includes a plurality of electrodes that provide a plurality of cardiac activity sensing electrode configurations. A sensing circuit provides a plurality of electrograms in response to cardiac activity sensed by the electrode configurations. A discriminator detects and discriminates between ischemia and myocardial infarction responsive to ST segments of the electrograms. The device may further discriminate an equivocal condition and initiate a secondary analysis for diagnosing spasm, anxiety, or exercised induced ischemia.

Claims

1. An implantable device that detects and discriminates between ischemia and myocardial infarction of a patient'"'"'s heart, the device comprising:

a plurality of electrodes that provide a plurality of cardiac activity sensing electrode configurations;

a sensing circuit that provides a plurality of electrograms in response to cardiac activity sensed by the electrode configurations;

a summer that provides a sum of the absolute value of the electrograms;

a divider that divides the electrogram absolute value sum by an amplitude of one of the electrograms to provide a normalized value; and

a discriminator that detects myocardial infarction and ischemia when the normalized value exceeds a predetermined value.

2. The device of claim 1 wherein the amplitude of one of the electrograms is an R wave amplitude.

3. An implantable device that detects and discriminates between ischemia and myocardial infarction of a patient'"'"'s heart, the device comprising:

a plurality of electrodes that provide a plurality of cardiac activity sensing electrode configurations;

a sensing circuit that provides a plurality of electrograms in response to cardiac activity sensed by the electrode configurations;

a summer that provides a sum of ST segments of the electrograms;

a divider that provides a normalized ST segment value from the ST segment sum; and

a discriminator that detects myocardial infarction when the normalized ST segment value is greater than a first value and detects ischemia when the normalized ST segment value is less than a second value.

4. An implantable device that detects and discriminates between ischemia and myocardial infarction of a patient'"'"'s heart, the device comprising:

a plurality of electrodes that provide a plurality of cardiac activity sensing electrode configurations;

a sensing circuit that provides a plurality of electrograms in response to cardiac activity sensed by the electrode configurations;

an arithmetic logic unit that provides an electrogram value of the electrograms; and

a discriminator that detects myocardial infarction when the electrogram value is greater than a first value, ischemia when the electrogram value is less than a second value, and an equivocal condition when the electrogram value is between the first and second values.

5. The device of claim 4 wherein the discriminator provides a secondary analysis in response to detecting an equivocal condition.

6. The device of claim 5 wherein the discriminator determines at least one of patient heart rate, physical activity, and posture during the secondary analysis.

7. An implantable device that detects and discriminates between ischemia and myocardial infarction of a patient'"'"'s heart, the device comprising:

a plurality of electrodes that provide a plurality of cardiac activity sensing electrode configurations;

a sensing circuit that provides a plurality of electrograms in response to cardiac activity sensed by the electrode configurations;

a discriminator that discriminates between an ischemic condition of the heart, a myocardial infarcted condition of the heart, and an equivocal condition of the heart responsive to ST segments of the plurality of electrograms, and in response to detecting an equivocal condition, determines at least one of patient heart rate, physical activity, and posture and detects and discriminates between spasm, anxiety, and exercise induced ischemia.

8. The device of claim 7 wherein the discriminator determines an ischemia burden responsive to detecting ischemia.

9. The device of claim 8 wherein the ischemia burden is proportional to ischemia duration.

10. An implantable device that discriminates between ischemia and myocardial infarction of a patient'"'"'s heart, the device comprising:

a plurality of electrodes that provide a plurality of sensing electrode configurations;

a sensing circuit that senses cardiac activity detected by the plurality of sensing electrode configurations to provide a plurality of cardiac activity signals; and

a discriminator that combines corresponding phases from the plurality of cardiac activity signals to obtain a phase value and detects myocardial infarction when the phase value is greater than a first value, ischemia when the phase value is less than a second value, and an equivocal condition when the phase value is between the first and second values.

11. The implantable device of claim 10, wherein the corresponding phases comprise ST segments of the cardiac activity from the plurality of sensing electrode configurations.

12. A method of discriminating between ischemia and myocardial infarction of a patient'"'"'s heart, the method comprising:

sensing cardiac activity of the heart with a plurality of cardiac activity sensing electrode configurations to provide a plurality of signals;

combining corresponding phases from the plurality of signals to obtain a phase value;

comparing the phase value to a first value and a second value; and

detecting myocardial infarction when the phase value is greater than the first value, ischemia when the phase value is less than the second value, and an equivocal condition when the phase value is between the first and second values.

13. The method of claim 12 further comprising determining an ischemia burden responsive to detecting ischemia.

14. The method of claim 12 further comprising conducting a secondary diagnosis responsive to detecting the equivocal condition.

15. The method of claim 14 wherein the secondary diagnosis includes determining at least one of heart rate, physical activity, and posture of the patient.

16. The method of claim 12 wherein the corresponding phases comprise ST segments and the phase value obtained comprises an ST segment value.

17. The method of claim 16 wherein comparing comprises detecting a myocardial infarction based on a positive ST segment value with respect to a baseline, and detecting ischemia based on a negative ST segment value with respect to a baseline.

18. A method comprising:

sensing cardiac activity of the heart with a plurality of cardiac activity sensing electrode configurations to provide a plurality of electrograms;

obtaining an electrogram value of the electrograms;

comparing the electrogram value to a first value and a second value; and

detecting myocardial infarction when the electrogram value is greater than the first value, ischemia when the electrogram value is less than the second value, and an equivocal condition when the electrogram value is between the first and second values.