Implantable medical device with inter-atrial block monitoring

• US 8,095,207 B2
• Filed: 01/23/2007
• Issued: 01/10/2012
• Est. Priority Date: 01/23/2006
• Status: Active Grant

• Current Assignee: Regents of The University of Minnesota (University of Minnesota)
• Original Assignee: Regents of The University of Minnesota (University of Minnesota)
• Inventors: Belalcazar, Andres, Patterson, Robert
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): Stoklosa, Joseph
• Application Number:
  US11/626,329
• Publication Number:
  US 20070203420A1
• Time in Patent Office: 1,813 Days
• Field of Search: 607/14, 607/17, 607/27, 607/9, 600/514, 600/509
• US Class Current: 600/512
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

An implantable medical device includes a voltage measurement circuit to measure a potential difference between implanted electrodes in a thorax of a living being, the potential difference resulting from an electrical P-wave cardiac signal. The implantable medical device also includes a processing unit to calculate a vector corresponding to the P-wave cardiac signal, the vector comprising a magnitude and a direction, and derived from measured potential differences and orientations defined by locations of the implanted electrodes. The implantable medical device further includes a monitoring unit to track a rotation of the vector corresponding to the P-wave cardiac signal. In various implementations, the monitoring unit may use the rotation to detect an inter-atrial block condition.

Claims

1. A system for monitoring disease status of a patient, comprising:

a first electrode, a second electrode, and a third electrode, each of the electrodes adapted for implantation in a human being, wherein the first electrode and the second electrode comprise a first pair of electrodes, and wherein the second electrode and the third electrode comprise a second pair of electrodes;

a voltage measurement circuit configured to measure a first voltage between the first electrode and the second electrode, and to measure a second voltage between the second electrode and the third electrode;

a memory unit that stores directional information comprising an angle between a first orientation defined by the first pair of electrodes and a second orientation defined by the second pair of electrodes; and

a processing unit configured to;

1) calculate, using the stored directional information and the measured first and second voltages, a first resultant vector comprising a magnitude and a direction;

2) calculate a vectorial difference between the first resultant vector and a second resultant vector, the second resultant vector having been previously calculated by the processing unit using the stored directional information and a previously measured third voltage between the first electrode and the second electrode and a previously measured fourth voltage between the second electrode and the third electrode; and

3) determine a disease status for the patient based on the calculated vectorial difference, and generate an alarm if the calculated vectorial difference satisfies a predetermined criterion.

2. The system of claim 1, wherein the disease status determination is a detection of an inter-atrial block condition.

3. The system of claim 1, wherein the first voltage and the second voltage are representative of a portion of an electrical P-wave cardiac signal associated with activation of a left atrium of a heart.

4. A method of monitoring cardiac pathologies in a human being, the method comprising:

measuring a first voltage between a first electrode and a second electrode and measuring a second voltage between the second electrode and a third electrode, wherein the first electrode and the second electrode comprise a first pair of electrodes, and wherein the second electrode and the third electrode comprise a second pair of electrodes;

calculating, using directional information that comprises an angle between a first orientation defined by the first pair of electrodes and a second orientation defined by the second pair of electrodes and using the measured first and second voltages, a first resultant vector comprising a magnitude and a direction;

calculating a vectorial difference between the first resultant vector and a second resultant vector, the second resultant vector having been previously calculated using the directional information and a previously measured third voltage between the first electrode and the second electrode and a previously measured fourth voltage between the second electrode and the third electrode; and

determining a disease status for the patient based on the calculated vectorial difference, and generating an alarm if the calculated vectorial difference satisfies a predetermined criterion.

5. A method of detecting fluid decompensation in a human being, the method comprising:

implanting a first electrode, a second electrode, and a third electrode within the human being, wherein the first electrode and the second electrode comprise a first pair of electrodes, and wherein the second electrode and the third electrode comprise a second pair of electrodes;

measuring a first voltage between the first electrode and the second electrode, and measuring a second voltage between the second electrode and the third electrode;

calculating, using directional information that comprises an angle between a first orientation defined by the first pair of electrodes and a second orientation defined by the second pair of electrodes and using the measured first and second voltages, a first resultant vector comprising a magnitude and a direction;

calculating a vectorial difference between the first resultant vector and a second resultant vector, the second resultant vector having been previously calculated using the directional information and a previously measured third voltage between the first electrode and the second electrode and a previously measured fourth voltage between the second electrode and the third electrode; and

determining a degree of fluid decompensation for the patient based on the calculated vectorial difference, and generating an alarm if the calculated vectorial difference satisfies a predetermined criterion.

6. The method of claim 5, wherein determining the degree of fluid decompensation comprises tracking a magnitude of the calculated vectorial difference.

7. The method of claim 5, wherein determining the degree of fluid decompensation comprises tracking a direction of the calculated vectorial difference.

8. A system for monitoring disease status of a patient, comprising:

a first electrode, a second electrode, a third electrode, and a fourth electrode, each of the electrodes adapted for implantation in a human being, wherein the first electrode and the second electrode comprise a first pair of electrodes, and wherein the third electrode and the fourth electrode comprise a second pair of electrodes;

a voltage measurement circuit configured to measure a first voltage between the first electrode and the second electrode, and to measure a second voltage between the third electrode and the fourth electrode;

a memory unit that stores directional information comprising an angle between a first orientation defined by the first pair of electrodes and a second orientation defined by the second pair of electrodes; and

a processing unit configured to;

1) calculate, using the stored directional information and the measured first and second voltages, a first resultant vector comprising a magnitude and a direction;

2) calculate a vectorial difference between the first resultant vector and a second resultant vector, the second resultant vector having been previously calculated by the processing unit using the stored directional information and a previously measured third voltage between the first electrode and the second electrode and a previously measured fourth voltage between the third electrode and the fourth electrode; and

3) determine a disease status for the patient based on the calculated vectorial difference, and generate an alarm if the calculated vectorial difference satisfies a predetermined criterion.

9. The system of claim 8, wherein the first voltage and the second voltage are representative of a portion of an electrical P-wave cardiac signal associated with activation of a left atrium of a heart.

10. The system of claim 8, wherein the processing unit detects, using measurements from the voltage measurement circuit:

i) a first measurement associated with a P-wave onset feature and a second measurement associated with a P-wave offset feature;

ii) a third measurement associated with a first midpoint that is midway in time between the first measurement and the second measurement; and

iii) a fourth measurement associated with a second midpoint that is midway in time between the second measurement and the third measurement; and

wherein the fourth measurement is a voltage representative of a portion of an electrical P-wave cardiac signal associated with an activation of a left atrium of a heart.