Cardiac pacer having input/output circuit programmable for use with unipolar and bipolar pacer leads

• US 4,558,702 A
• Filed: 01/21/1983
• Issued: 12/17/1985
• Est. Priority Date: 01/21/1983
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Martucci, James P., Barreras, Francisco J.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/459,806
• Time in Patent Office: 1,061 Days
• Field of Search: 128/419 PG
• US Class Current: 607/30
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: Y10S 128/902 Biological signal amplifier

Abstract

An implantable cardiac pacer having atrial and ventricular electrodes includes an input/output circuit which can be programmed for use with either unipolar or bipolar pacer leads. The circuit can be reprogrammed by the physician after implant to accommodate physiological changes in the patient or chronic changes in pacer lead characteristics, and can be utilized with single channel or dual channel cardiac pacers.

Claims

1. In a cardiac pacer selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied mode designation signal, an input/output circuit comprising:

a source of unidirectional current including a signal ground;

pacer lead terminal means including a cathode electrode and an anode electrode;

a differential sense amplifier operable from said current source, said amplifier having inverting and non-inverting input terminals and providing a sense signal in response to a non-common mode signal applied to said input terminals;

first coupling means for coupling one of said electrodes to one input terminal of said differential amplifier;

second coupling means for coupling the other of said electrodes to the remaining input terminal of said differential amplifier;

means including an output amplifier for generating a pacing pulse, said output amplifier having an output terminal;

third coupling means for coupling said other electrode to said output terminal;

reference terminal means including a reference electrode for establishing electrical contact with a patient'"'"'s body;

first switching means responsive to a first applied control signal for electively connecting said one electrode to said signal ground;

second switching means responsive to a second applied control signal for selectively connecting said one input terminal of said differential amplifier to said signal ground;

third switching means responsive to a third applied control signal for selectively connecting said reference electrode to said signal ground; and

mode control means for generating said first, second and third mode control signals in response to the mode designation signal whereby said first and second switching means are open and said third switching means are closed for unipolar pacing, said first switching means are closed and said second and third switching means are open for bipolar pacing, said first switching means are open and said second and third switching means are closed for unipolar sensing, and said first and second switching means are open for bipolar sensing.

2. A cardiac pacer as defined in claim 1 wherein said switch devices each comprise transistors.

3. A cardiac pacer as defined in claim 1 wherein said coupling means each comprise a capacitor.

6. A cardiac pacer as defined in claims 1 or 4 including telemetering means responsive to an externally applied signal for conditioning said mode control means.

4. In a cardiac pacer having atrial and ventricular input/output terminals and selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, an input/output circuit comprising:

a source of unidirectional current including a signal ground;

atrial pacer lead terminal means including a cathode electrode and an anode electrode;

a differential atrial sense amplifier operable from said unidirectional current source, said amplifier having inverting and non-inverting input terminals and providing an atrial sense signal in response to a non-common mode signal applied to said input terminals;

first atrial coupling means for coupling one of said atrial electrodes to one input terminal of said atrial sense amplifier;

second atrial coupling means for coupling the other of said atrial electrodes to the other input terminal of said atrial sense amplifier;

means including an atrial output amplifier for generating an atrial pacing pulse, said atrial output amplifier having an atrial output terminal;

third atrial coupling means for coupling said other atrial electrode to said atrial output terminal;

ventricular pacing lead terminal means including a cathode electrode and an anode electrode;

a differential ventricular sense amplifier operable from said unidirectional current source, said amplifier having inverting and non-inverting input terminals and providing a ventricular sensd signal in response to a non-common mode signal applied to said input terminals;

first ventricular coupling means for coupling one of said ventricular electrodes to one input terminal of said ventricular sense amplifier;

second ventricular coupling means for coupling the other of said ventricular electrodes to the other input terminal of said ventricular sense amplifier;

means including a ventricular output amplifier for generating a ventricular pacing pulse, said ventricular output amplifier having a ventricular output terminal;

third ventricular coupling means for coupling said other ventricular electrode to said ventricular output terminal;

reference terminal means including a reference electrode for establishing electrical contact with a patient'"'"'s body;

first atrial and ventricular switching means responsive to a first applied control signal for selectively connecting said one electrode to said signal ground;

second atrial and ventricular switching means responsive to a second applied control signal for selectively connecting said one input terminal of said differential amplifier to said signal ground;

third switching means responsive to a third applied control signal for selectively connecting said reference electrode to said signal ground; and

mode control means for generating said first, second and third mode control signals in response to the mode designation signal whereby said first and second switching means are open and said third switching means are closed for unipolar pacing said first switching means are closed and said second and third switching means are open for bipolar pacing, said first switching means are open and said second and third switching means are closed for unipolar sensing, and said first and second switching means are open for bipolar sensing.

5. A cardiac pacer as defined in claim 4 wherein said switch devices each comprise transistors.

7. A cardiac pacer as defined in claim 4 wherein said coupling means each comprise a capacitor.