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

Claim 2

In a cardiac pacer (10) selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, an input circuit comprising, in combination: pacer lead terminal means (20;21) including a cathode electrode (22;24) and an anode electrode (23;25); a first differential amplifier (37) having inverting and non-inverting inputs; coupling means for connecting one of said electrodes (22) to said inverting input and the other of said electrodes (23) to said non-inverting input; reference electrode means (27) adapted for electrical contact with the patient's body; first, second and third switching means responsive to first, second and third applied mode control signals for selectively connecting repective ones of said electrodes to ground; and mode control means responsive to an applied mode designation signal for generating first, second and third mode control signals to selectively condition said switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing at said terminal means (20;21)

Claim 3

A cardiac pacer as defined in claim 1 wherein said swith devices comprise transistors (45, 46, 47; 55, 56, 57; 63).

Claim 4

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

Claim 5

A cardiac pacer as defined in claim 1 wherein said coupling means comprise a pair of capacitors (38, 40; 49, 51) connected in series with respective ones of said input terminals.

Claim 6

A cardiac pacer as defined in claim 1 wherein said first and second switching means are non-conductive for bipolar sensing, and said first switching means is conductive and said second switching means in non-conductive for unipolar sensing.

Claim 7

A cardiac pacer as defined in claim 5 wherein said third switching means is conductive for both bipolar and unipolar sensing.

Claim 8

In a cardiac pacer having atrial and ventricular input/output terminals (20;21) selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command singal, comprising, in combination: atrial pacer lead terminal means (20) including a cathode electrode (22) and an anode electrode (23); a first differential amplifier (37) having inverting and non-inverting inputs; first coupling means for connecting one (22) of said atrial electrodes to said inverting input and the other (23) of said atrial electrodes to said non-inverting input. ventricular pacer lead terminal means (21) including a cathode electrode (24) and an anode electrode (25); a second differential amplifier (48) having inverting and non-inverting inputs; second coupling means for connecting one (24) of said ventricular electrodes to said inverting input and the other (25) of said ventricular electrodes to said non-inverting input; reference electrode means (27) adapted for electrical contact with the patient's body; first and second atrial and ventricular switching means responsive to first and second applied atrial and ventricular mode control signals for selectively connecting respective ones of said atrial and ventricular electrodes to signal ground; reference electrode switching means responsive to an applied mode control signal for selectively connecting said reference electrode to signal ground; and mode control means responsive to an applied mode designation signal for generating first and second atrial and ventricular mode control signals and a reference mode control signal to selectively condition said switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing at said atrial and ventricular terminals.

Claim 9

In a cardiac pacer having atrial and ventricular input/output terminals (20;21) selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command singal, comprising, in combination: atrial pacer lead terminal means (20) including a cathode electrode (22) and an anode electrode (23); a first differential amplifier (37) having inverting and non-inverting inputs; first coupling means for connecting one (22) of said atrial electrodes to said inverting input and the other (23) of said atrial electrodes to said non-inverting input. ventricular pacer lead terminal means (21) including a cathode electrode (24) and an anode electrode (25); a second differential amplifier (48) having inverting and non-inverting inputs; second coupling means for connecting one (24) of said ventricular electrodes to said inverting input and the other (25) of said ventricular electrodes to said non-inverting input; reference electrode means (27) adapted for electrical contact with the patient's body; first and second atrial and ventricular switching means responsive to first and second applied atrial and ventricular mode control signals for selectively connecting respective ones of said atrial and ventricular electrodes to signal ground; reference electrode switching means responsive to an applied mode control signal for selectively connecting said reference electrode to signal ground; and mode control means responsive to an applied mode designation signal for generating first and second atrial and ventricular mode control signals and a reference mode control signal to selectively condition said switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing at said atrial and ventricular terminals.

Claim 10

A cardiac pacer as defined in claim 7 wherein said switch devices each comprise transistors (45, 46, 47; 55, 56, 57; 63).

Claim 11

A cardiac pacer as defined in claim 7 including telemetering means (34) responsive to an externally applied signal for conditioning said mode control means.

Claim 12

A cardiac pacer as defined in claim 7 wherein said coupling means each comprise a pair of capacitors (38, 40; 49, 51) connected in series with respective ones of said atrial and ventricular input terminals (20;21).

Claim 13

A cardiac pacer as defined in claim 7 wherein said first and second atrial and ventricular switching means are non-conductive for bipolar sensing and said first atrial and ventricular switching means are conductive and said second atrial and ventricular switching means are non-conductive for unipolar sensing.

Claim 14

A cardiac pacer as defined in claim 11 wherein said reference switching means (63) is conductive for both bipolar and unipolar sensing.

Claim 15

In a cardiac pacer selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, an input/output circuit comprising: pacer lead terminal means (20;21) including a cathode electrode (22;24) and an anode electrode (23;25); a first differential amplifier (37) having inverting and non-inverting inputs; first coupling means for connecting one (22)of said electrodes to said inverting input; second coupling means for connecting the other (23) of said electrodes to said non-inverting input; an output amplifier having an output electrode; third coupling means for connecting said other of said electrodes to said output electrode; reference electrode means (27) adapted for electrical contact with the patient's body; first, second and third switching means responsive to first, second and third applied mode control signals for selectively connecting said anode, cathode and reference electrodes to ground; and mode control means responsive to an applied mode designation signal for generating first, second and third mode control signals to selectively condition said switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing and/or pacing at said terminal means (20;21).

Claim 16

In a cardiac pacer selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, an input/output circuit comprising: pacer lead terminal means (20;21) including a cathode electrode (22;24) and an anode electrode (23;25); a first differential amplifier (37) having inverting and non-inverting inputs; first coupling means for connecting one (22)of said electrodes to said inverting input; second coupling means for connecting the other (23) of said electrodes to said non-inverting input; an output amplifier having an output electrode; third coupling means for connecting said other of said electrodes to said output electrode; reference electrode means (27) adapted for electrical contact with the patient's body; first, second and third switching means responsive to first, second and third applied mode control signals for selectively connecting said anode, cathode and reference electrodes to ground; and mode control means responsive to an applied mode designation signal for generating first, second and third mode control signals to selectively condition said switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing and/or pacing at said terminal means (20;21).

Claim 17

A cardiac pacer as defined in claim 13 wherein said switch devices each comprise transistors.

Claim 18

A cardiac pacer as defined in claim 13 wherein said coupling means each comprise capacitors connected in series with respective ones of said in put terminals.

Claim 19

A cardiac pacer as defined in claim 13 wherein said first and second switching means are non-conductive for bipolar sensing, and said first switching means is conductive and said second switching means is non-conductive for unipolar sensing.

Claim 20

A cardiac pacer as defined in claim 5 wherein said third switching means is conductive for both bipolar and unipolar sensing.

Claim 21

A cardiac pacer as defined in claim 13 wherein said third switching means are non-conductive during bipolar pacing, and conductive during unipolar pacing.

Claim 22

In a cardiac pacer having atrial and ventricular input/output terminals (20;21) selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, comprising, in combination: atrial pacer lead terminal means (20) including a cathode electrode (22) and an anode electrode (23); a first differential amplifier (37) having inverting and non-inverting atrial inputs; first atrial coupling means for connecting one of said atrial electrodes to said inverting atrial input; second atrial coupling means for connecting the other of said atrial electrodes to said non-inverting atrial input; an atrial output amplifier having an atrial output terminal; third atrial coupling means for connecting said other atrial electrode to said atrial output terminal; ventricular pacing lead terminal means (21) including a cathode electrode (24) and an anode electrode (25); a second differential amplifier (48) having inverting and non-inverting ventricular inputs; first ventricular coupling means for connecting one of said ventricular electrodes to said inverting input; second ventricular coupling means for connecting the other of said ventricular electrodes to said non-inverting ventricular input; a ventricular output amplifier having a ventricular output terminal; third ventricular coupling means for connecting said other ventricular electrode to said ventricular output terminal; reference electrode means(27) adapted for electrical contact with the patient's body; reference electrode switching means (63) responsive to an applied mode control signal for selectively connecting said reference electrode to signal ground; first and second atrial switching means responsive to first and second applied atrial mode control signals for selectively connecting respective ones of said atrial electrodes to signal ground; first and second ventricular switching means responsive to first and second applied ventricular mode control signals for selectively connecting respective ones of said ventricular electrodes to signal ground; and mode control means responsive to an applied mode designation signal for generating first and second atrial and ventricular mode control signals to selectively condition said atrial and ventricular switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing at said terminal means.

Claim 23

In a cardiac pacer having atrial and ventricular input/output terminals (20;21) selectively operable in unipolar and bipolar pacing and sensing modes in response to an applied command signal, comprising, in combination: atrial pacer lead terminal means (20) including a cathode electrode (22) and an anode electrode (23); a first differential amplifier (37) having inverting and non-inverting atrial inputs; first atrial coupling means for connecting one of said atrial electrodes to said inverting atrial input; second atrial coupling means for connecting the other of said atrial electrodes to said non-inverting atrial input; an atrial output amplifier having an atrial output terminal; third atrial coupling means for connecting said other atrial electrode to said atrial output terminal; ventricular pacing lead terminal means (21) including a cathode electrode (24) and an anode electrode (25); a second differential amplifier (48) having inverting and non-inverting ventricular inputs; first ventricular coupling means for connecting one of said ventricular electrodes to said inverting input; second ventricular coupling means for connecting the other of said ventricular electrodes to said non-inverting ventricular input; a ventricular output amplifier having a ventricular output terminal; third ventricular coupling means for connecting said other ventricular electrode to said ventricular output terminal; reference electrode means(27) adapted for electrical contact with the patient's body; reference electrode switching means (63) responsive to an applied mode control signal for selectively connecting said reference electrode to signal ground; first and second atrial switching means responsive to first and second applied atrial mode control signals for selectively connecting respective ones of said atrial electrodes to signal ground; first and second ventricular switching means responsive to first and second applied ventricular mode control signals for selectively connecting respective ones of said ventricular electrodes to signal ground; and mode control means responsive to an applied mode designation signal for generating first and second atrial and ventricular mode control signals to selectively condition said atrial and ventricular switching devices between conductive and non-conductive states to provide bipolar and/or unipolar sensing at said terminal means.

Claim 24

A cardiac pacer as defined in claim 19 wherein said switch devices each comprise transistors (45, 46, 47; 55, 56, 57; 63).

Claim 25

A cardiac pacer as defined in claim 19 including telemetering means responsive to an externally applied signal for conditioning said mode control means.

Claim 26

A cardiac pacer as defined in claim 19 wherein said atrial and ventricular coupling means each comprise a pair of capacitors (38, 40; 49,51) connected in series with respective ones of said atrial and ventricular input terminals.

Claim 27

A cardiac pacer as defined in claim 19 wherein said first and second atrial and ventricular switching means are non-conductive for bipolar sensing and said first atrial and ventricular switching means are conductive and said second atrial and ventricular switching means arenon-conductive for unipolar sensing.

Claim 28

A cardiac pacer as defined in claim 23 wherein said reference switching means (63) is conductive for both bipolar and unipolar sensing.

Claim 29

A cardiac pacer as defined in claim 19 wherein said reference switching means (63) are non-conductive during bipolar pacing, and conductive during unipolar pacing.