Multi-site impedance sensor using coronary sinus/vein electrodes

• US 6,278,894 B1
• Filed: 06/21/1999
• Issued: 08/21/2001
• Est. Priority Date: 06/21/1999
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Nugent, Kevin G., Kadhiresan, V. A., Salo, Rodney W.
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): SZMAL, BRIAN SCOTT
• Application Number:
  US09/336,449
• Time in Patent Office: 792 Days
• Field of Search: 600/547, 600/300, 607/24, 607/6, 607/8
• US Class Current: 600/547
• 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 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium

Abstract

A method and apparatus for performing impedance plethysmography on a living heart for diagnostic and therapy purposes involves placement of plural leads where at least one is disposed within a coronary vein traversing the myocardium on the left side of the heart with another lead having plural electrodes thereon disposed in the right ventricle. By appropriate selection of electrodes on the first and second leads for driving with an AC carrier signal and other such electrodes coupled to a sensing amplifier, an impedance vs. time signal can be derived that when signal processed provides useful information concerning cardiac performance. The multi-site impedance sensing has been found to yield more robust data especially in patients having CHF.

Claims

1. A method of carrying out impedance plethysmography on a living heart, comprising the steps of:

(a) installing a first lead having a plurality of electrodes in a right ventricular chamber of said living heart;

(b) installing a second lead having a plurality of electrodes in a coronary vein on the left ventricle of said heart;

(c) coupling a subthreshold AC drive signal between selected ones of the electrodes on the first and second leads;

(d) coupling a signal sensing circuit between at least one electrode on the second lead and another selected one of the electrodes on one of the first and second leads; and

(e) extracting a signal representative of electrical impedance from the signal sensing circuit.

2. A method for carrying out impedance plethysmography on a living heart, comprising the steps of:

(a) installing a first lead including at least two electrodes in a right ventricular chamber of said heart;

(b) installing a second lead including a plurality of electrodes in a coronary vein on the left ventricle of the heart;

(c) coupling a subthreshold AC drive signal source between one of

(i) the at least two electrodes on the first lead,

(ii) one of the at least two electrodes on the first lead and a first of the plurality of electrodes on the second lead,

(iii) the first and a second of the plurality of electrodes on the second lead;

(d) coupling a signal sensing circuit between

(i) a third and a fourth electrode on the second lead when the AC drive signal is coupled to the at least two electrodes on the first lead,

(ii) the other of the at least two electrodes on the first lead and the first of the plurality of the electrodes on the second lead when the AC drive signal is coupled to one of the at least two electrodes on the first lead and the third of the plurality of electrodes on the second lead,

(iii) the third and fourth of the plurality of electrodes on the second lead when the AC drive signal is coupled to the first and second of the plurality of electrodes on the second lead; and

(e) extracting a signal representative of electrical impedance from the signal sensing circuit.

3. A method for carrying out impedance plethysmography comprising the steps of:

(a) installing a first lead including at least two electrodes in a right ventricular chamber of said heart;

(b) installing a second lead including a plurality of electrodes in a coronary vein on the left ventricle of the heart;

(c) installing a third lead having an electrode in a right atrial chamber of the heart;

(d) coupling an AC drive signal source between one of;

(i) the at least two electrodes on the first lead,

(ii) one of the at least two electrodes on the first lead and a first of the plurality of electrodes on the second lead,

(iii) the first and a second of the plurality of electrodes on the second lead,

(iv) the electrode on the third lead and one of the electrodes on the first lead;

(e) coupling a signal sensing circuit between;

(i) a third and a fourth of the plurality of electrodes on the second lead when the AC drive signal is coupled to the at least two electrodes on the first lead,

(ii) the other of the at least two electrodes on the first lead and the third of the plurality of electrodes on the second lead when the AC drive signal is coupled to one of the at least two electrodes on the first lead and a third of the plurality of electrodes on the second lead,

(iii) the third and a fourth of the plurality of electrodes on the second lead when the AC drive signal is coupled to the first and second of the plurality of electrodes on the second lead,

(iv) the first and the third of the plurality of electrodes on the second lead or the other electrode on the first lead and the third of the plurality of electrodes on the second lead when the AC drive signal is coupled to the electrode on the third lead and one of the electrodes on the first lead; and

(f) extracting a signal representative of the electrical impedance from the signal sensing circuit.

4. A method for carrying out impedance plethysmography on a living heart, comprising the steps of:

(a) installing a first lead in a right ventricle of the heart, the first lead including at least two electrodes RV₁ and RV₂ thereon disposed in the right ventricle;

(b) installing a second lead in a coronary vein on the left ventricle of the heart, the second lead including a plurality of electrodes including at least two of CS₁, CS₂, CS₃ and CS₄ thereon;

(c) coupling a source of subthreshold AC drive signals and a signal sensing circuit to predetermined pairs of said electrodes in accordance with an entry in the following table;

5. The method of claim 4 and further including the steps of:

(a) installing a third lead in a right atrial chamber, the third lead including an electrode RA₁ thereon; and

(b) coupling the source of subthreshold AC drive signals and the sensing circuit to predetermined pairs of said electrodes in accordance with an entry in the following table;

6. An apparatus for conducting impedance plethysmography on a living heart, comprising:

(a) a first electrical lead having a plurality of electrodes adapted for placement in a coronary vein on the left ventricular chamber of said heart;

(b) a second lead having a plurality of electrodes and adapted for placement in a right ventricular chamber of the heart;

(c) means for applying a subthreshold AC carrier signal across selected ones of said plurality of electrodes on one or both of the first and second electrical leads;

(d) means for sensing electrical signals connected across a pair of said plurality of electrodes where at least one of said pair of electrodes is on the first electrical lead; and

(e) means connected to the sensing means for demodulating the sensed electrical signals.

7. Apparatus for carrying out impedance plethysmography on a living heart, comprising:

(a) a first lead having a plurality of electrodes adapted for placement in a right ventricular chamber of said heart;

(b) a second lead having a plurality of electrodes adapted for placement in a coronary vein on the left ventricle of the heart;

(c) a source of AC drive signals;

(d) a switching circuit for connecting said source of AC drive signals to selected ones of the electrodes on the first and second leads;

(e) a signal sensing circuit coupled by the switching circuit to at least one electrode on the second lead and another electrode on the second lead and another electrode on one of the first and second leads; and

(f) a demodulator coupled to the signal sensing circuit, the demodulator extracting a signal proportional to the electrical impedance between said at least one electrode on the second lead and said another electrode on one of the first and second leads.

8. An apparatus for carrying out impedance plethysmography on a living heart, comprising:

(a) a first electrical lead having at least two electrodes thereon adapted for placement in the right ventricular chamber of said heart;

(b) a second electrical lead having a plurality of electrodes thereon adapted for placement in a coronary vein on the left ventricle of said heart;

(c) a source of AC drive signals;

(d) a signal sensing circuit;

(e) a switching circuit for connecting said source and said sensing circuit to the electrodes on the first and second leads in accordance with an entry in the following table;

9. The apparatus of claim 8 and further including:

(a) a third lead adapted for placement in the right atrium of the heart, the third lead including an electrode RA₁ thereon;

said switching circuit connecting said source and said sensing circuit to the electrodes on the first, second and third leads in accordance with an entry in the following table;