Atrio-ventricular demand pacer with atrial stimuli discrimination

Claim 2

An atrial and ventricular pacer comprising a first pair of terminals for connection to a patient''s heart for atrial stimulation, a second pair of terminals for connection to said patient''s heart for ventricular stimulation, means coupled to said second pair of terminals for detecting an electrical signal thereon resulting from the beating of said patient''s heart, means for generating electrical stimuli on said fist and second pairs of terminals in accordance with the time at which the beating of said patient''s heart is detected, and means for preventing the operation of said detecting means responsive to the appearance on said second pair of terminals of an electrical signal resulting from the generation of an electrical stimulus on said first pair of terminals.

Claim 3

An atrial and ventricular pacer in accordance with claim 1 wherein stimuli are generated on said first pair of terminals at intervals which are shorter than the normal interval between successive R waves in the electrocardiographic waveform of said patient and are longer than the normal interval between an R wave and the next P wave in the electrocardiographic waveform of said patient, and stimuli are generated on said second pair of terminals at intervals which are longer than the normal interval between successive R waves in the electrocardiographic waveform of said patient.

Claim 4

An atrial and ventricular pacer in accordance with claim 2 wherein said electrical stimuli generating means includes a pulse generating circuit and transformer means for coupling said pulse generating circuit to said first pair of terminals.

Claim 5

An atrial and ventricular pacer in accordance with claim 3 wherein the electrical stimuli generated on said first pair of terminals are much narrower than the width of a normal QRS waveform and said preventing means includes a low-pass filter for attenuating the relatively high-frequency signal components contained in the electrical signal appearing on said second pair of terminals resulting from the generation of an electrical stimulus on said first pair of terminals.

Claim 6

An atrial and ventricular pacer in accordance with claim 4 further including means responsive to the operation of said detecting means at a rate greater than a predetermined rate for controlling the generation of stimuli on said second pair of terminals at a rate independent of the detection of the beating of said patient''s heart, said controlling means including a capacitor, first resistance means connected in series with said capacitor, means responsive to the operation of said detecting means for applying a current pulse to said first resistance means for charging said capacitor, second resistance means connected between said first resistance means and said capacitor for discharging said capacitor between applications thereto of successive current pulses, said electrical stimuli generating means operating in accordance with an instantaneous rise in potential greater than a predetermined value across said capacitor wiTh the application of one of said current pulses, and means for reducing the discharge time constant of said capacitor.

Claim 7

An atrial and ventricular pacer in accordance with claim 5 wherein said discharge time constant reducing means includes a diode connected across said first resistance means poled in the direction of the flow of discharge current from said capacitor.

Claim 8

An atrial and ventricular pacer in accordance with claim 1 wherein said electrical stimuli generating means includes a pulse generating circuit and transformer means for coupling said pulse generating circuit to said first pair of terminals.

Claim 9

An atrial and ventricular pacer in accordance with claim 7 wherein the electrical stimuli generated on said first pair of terminals are much narrower than the width of a normal QRS waveform and said preventing means includes a low-pass filter for attenuating the relatively high-frequency signal components contained in the electrical signal appearing on said second pair of terminals resulting from the generation of an electrical stimulus on said first pair of terminals.

Claim 10

An atrial and ventricular pacer in accordance with claim 8 further including means responsive to the operation of said detecting means at a rate greater than a predetermined rate for controlling the generation of stimuli on said second pair of terminals at a rate independent of the detection of the beating of said patient''s heart, said controlling means including a capacitor, first resistance means connected in series with said capacitor, means responsive to the operation of said detecting means for applying a current pulse to said first resistance means for charging said capacitor, second resistance means connected between said first resistance means and said capacitor for discharging said capacitor between applications thereto of successive current pulses, said electrical stimuli generating means operating in accordance with an instantaneous rise in potential greater than a predetermined value across said capacitor with the application of one of said current pulses, and means for reducing the discharge time constant of said capacitor.

Claim 11

An atrial and ventricular pacer in accordance with claim 9 wherein said discharge time constant reducing means includes a diode connected across said first resistance means poled in the direction of the flow of discharge current from said capacitor.

Claim 12

An atrial and ventricular pacer in accordance with claim 1 wherein the electrical stimuli generated on said first pair of terminals are much narrower than the width of a normal QRS waveform and said preventing means includes a low-pass filter for attenuating the relatively high-frequency signal components contained in the electrical signal appearing on said second pair of terminals resulting from the generation of an electrical stimulus on said first pair of terminals.

Claim 13

An atrial and ventricular pacer in accordance with claim 11 further including means responsive to the operation of said detecting means at a rate greater than a predetermined rate for controlling the generation of stimuli on said second pair of terminals at a rate independent of the detection of the beating of said patient''s heart, said controlling means including a capacitor, first resistance means connected in series with said capacitor, means responsive to the operation of said detecting means for applying a current pulse to said first resistance means for charging said capacitor, second resistance means connected between said first resistance means and said capacitor for discharging said capacitor between applications thereto of successive current pulses, said electrical stimuli generating means operating in accordance with an instantaneous rise in potential greater than a predetermined value across said capacitor with the application of one of said current pulses, and means for reducing the discharge time constant of said capacitor.

Claim 14

An atrial and ventricular pacer in accordance with claim 12 wherein said discharge time constant reducing means includes a diode connected across said first resistance means poled in the direction of the flow of discharge current from said capacitor.

Claim 15

An atrial and ventricular pacer comprising terminal means for connection to a patient''s heart for atrial stimulation, terminal means for connection to said patient''s heart for ventricular stimulation, a first timing circuit connected to said atrial terminal means for generating an electrical impulse on said atrial terminal means, a second timing circuit connected to said ventricular terminal means for generating an electrical impulse on said first and said ventricular terminal means, means continuously operative for detecting a signal on said ventricular terminal means corresponding to a ventricular contraction of said patient''s heart, means responsive to the operation of said detecting means for resetting said second timing circuit, and means for preventing the operation of said resetting means responsive to the operation of said detecting means when a signal appears on said ventricular terminal means as a result of the generation of an electrical impulse on said atrial terminal means.

Claim 16

An atrial and ventricular pacer comprising terminal means for connection to a patient''s heart for atrial stimulation, terminal means for connection to said patient''s heart for ventricular stimulation, a first timing circuit connected to said atrial terminal means for generating an electrical impulse on said atrial terminal means, a second timing circuit connected to said ventricular terminal means for generating an electrical impulse on said first and said ventricular terminal means, means continuously operative for detecting a signal on said ventricular terminal means corresponding to a ventricular contraction of said patient''s heart, means responsive to the operation of said detecting means for resetting said second timing circuit, and means for preventing the operation of said resetting means responsive to the operation of said detecting means when a signal appears on said ventricular terminal means as a result of the generation of an electrical impulse on said atrial terminal means.

Claim 17

An atrial and ventricular pacer in accordance with claim 14 wherein the electrical impulse generated on said atrial terminal means is much narrower than the width of a normal QRS waveform and said preventing means includes a low-pass filter for attenuating the relatively high-frequency signal components contained in the electrical signal appearing on said ventricular terminal means resulting from the generation of an electrical impulse on said atrial terminal means.

Claim 18

An atrial and ventricular pacer in accordance with claim 15 further including means responsive to the operation of said detecting means at a rate greater than a predetermined rate for controlling the generation of electrical impulses on said ventricular terminal means at a rate independent of the detection of signals on said ventricular terminal means corresponding to ventricular contractions of said patient''s heart, said controlling means including a capacitor, first resistance means connected in series with said capacitor, means responsive to the operation of said detecting means for applying a current pulse to said first resistance means for charging said capacitor, second resistance means connected between said first resistance means and said capacitor for discharging said capacitor between applications thereto of successive current pulses, said second timing means operating in accordance with an instantaneous rise in potential greater than a predetermined value across said capacitor with the application of one of said current pulses, and means for reducing the discharge time constant of said capacitor.

Claim 19

An atrial and ventricular pacer in accordance with claim 16 wherein said discharge time constant reducing means includes a diode connected across said first resistance means poled in the direction of the flow of discharge current from said capacitor.

Claim 20

An atrial and ventricular pacer in accordance with claim 14 further including means responsive to the operation of said detecting means at a rate greater than a predetermined rate for controlling the generation of electrical impulses on said ventricular terminal means at a rate independent of the detection of signals on said ventricular terminal means corresponding to ventricular contractions of said patient''s heart, said controlling means including a capacitor, first resistance means connected in series with said capacitor, means responsive to the operation of said detecting means for charging said capacitor, second resistance means connected between said first resistance means and said capacitor for discharging said capacitor between applications thereto of successive current pulses, said second timing means operating in accordance with an instantaneous rise in potential greater than a predetermined value across said capacitor with the application of one of said cuRrent pulses, and means for reducing the discharge time constant of said capacitor.

Claim 21

An atrial and ventricular pacer in accordance with claim 18 wherein said discharge time constant reducing means includes a diode connected across said first resistance means poled in the direction of the flow of discharge current from said capacitor.

Claim 22

An atrial and ventricular pacer comprising terminal means for connection to a patient''s heart for atrial stimulation, terminal means for connection to said patient''s heart for ventricular stimulation, a first timing circuit connected to said atrial terminal means for generating an electrical impulse on said atrial terminal means, a second timing circuit connected to said ventricular terminal means for generating an electrical impulse on said ventricular terminal means, means for detecting a signal corresponding to a ventricular contraction of said patient''s heart, means responsive to the operation of said detecting means for resetting said first and second timing circuits, and switch means for preventing the resetting of only said second timing circuit responsive to the operation of said detecting means.

Claim 23

An atrial and ventricular pacer comprising terminal means for connection to a patient''s heart for atrial stimulation, terminal means for connection to said patient''s heart for ventricular stimulation, a first timing circuit connected to said atrial terminal means for generating an electrical impulse on said atrial terminal means, a second timing circuit connected to said ventricular terminal means for generating an electrical impulse on said ventricular terminal means, means for detecting a signal corresponding to a ventricular contraction of said patient''s heart, means responsive to the operation of said detecting means for resetting said first and second timing circuits, and switch means for preventing the resetting of only said second timing circuit responsive to the operation of said detecting means.

Claim 24

An atrial and ventricular pacer in accordance with claim 20 wherein said atrial terminal means includes first and second electrodes and said ventricular terminal means includes third and fourth electrodes.

Claim 25

An atrial and ventricular pacer in accordance with claim 21 wherein said detecting means includes means for providing continuous operation of said detecting means.

Claim 26

An atrial and ventricular pacer in accordance with claim 20 wherein said detecting means includes means for providing continuous operation of said detecting means.

Claim 27

A pacer comprising terminal means for connection to a patient''s heart for atrium and ventricle stimulation, means for detecting electrical signals on said terminal means resulting from beating of said ventricle, and means controlled by operation of said detecting means for generating electrical stimulii on said terminal means for stimulating said atrium and said ventricle in a predetermined timing sequence.

Claim 28

A pacer comprising terminal means for connection to a patient''s heart for atrium and ventricle stimulation, means for detecting electrical signals on said terminal means resulting from beating of said ventricle, and means controlled by operation of said detecting means for generating electrical stimulii on said terminal means for stimulating said atrium and said ventricle in a predetermined timing sequence.