Telemetry apparatus and method for implantable tissue stimulator

Claim 2

A living tissue stimulator apparatus comprising: implantable stimulator means for selectively producing electrical stimulus signals; an electrical lead adapted to carry the stimulus signals from the stimulator means to the tissue; telemetry means mounted with implantable means for producing a telemetry signal and for transmitting it therefrom; and external receiver means for receiving the telemetry signal transmitted by the telemetry means; wherein the telemetry means includes means for coupling the telemetry signal onto the electrical lead, for radiation outwardly to the receiver means.

Claim 3

A living tissue stimulator apparatus as defined in claim 1, wherein: the apparatus further includes a metallic case for housing the implantable stimulator means and telemetry means, and a second electrical lead adapted to carry the stimulus signals from the simulator means to the tissue to be stimulated; and the telemetry means includes means for applying the telemetry signal between the two electrical leads and the case, the provide a dipole antenna.

Claim 4

A living tissue stimulator apparatus as defined in claim 1, wherein the telemetry means includes: digital means for providing a digital telemetry signal; and modulator means for pulse-modulating a carrier signal with the digital telemetry signal, for coupling onto the electrical lead and radiation outwardly to the receiver means.

Claim 5

A living tissue stimulator apparatus as defined in claim 3, wherein: the living tissue to be stimulated is heart muscle tissue; the apparatus is a pacemaker adapted to stimulate the heart muscle tissue; the apparatus further includes means for monitoring electrical signals generated by the heart and for producing a corresponding analog electrocardiogram signal; and the telemetry means includes analog-to-digital converter means for digitizing the analog electrocardiogram signal to produce a digitized electrocardiogram signal.

Claim 6

A living tissue stimulator apparatus as defined in claim 4, wherein the telemetry means further includes: memory means for storing digital data; and multiplexing means for multiplexing the digital data stored by the memory means with the digitized electrocardiogram signal provided by the analog-to-digital converter means, to produce the digital telemetry signal.

Claim 7

A living tissue stimulator apparatus as defined in claim 3, wherein: the digital telemetry signal includes a succession of bits, each having either a first state or a second state; and the modulator means includes means for providing a single burst of the carrier signal when a bit of the telemetry signal has the first state and an absence of the carrier signal when a bit has the second state.

Claim 8

A living tissue stimulator apparatus as defined in claim 6, wherein: the single burst of the carrier signal, provided by the modulator means when a bit of the telemetry signal has the first state has a duty cycle of less than about 0.2; and the carrier signal modulated by the telemetry means has a frequency in the range of 10 to 300 megahertz.

Claim 9

A living tissue stimulator apparatus comprising: implantable stimulator means for selectively producing electrical stimulus signals for transmission to living tissue; an electrical lead adapted to carry the stimulus signals from the implantable stimulator means to the tissue; telemetry means mounted with the stimulator means for producing a telemetry signal and for transmitting the telemetry signal therefrom, the telemetry means including digital means for producing a digital telemetry signal, modulator means for pulse modulating a carrier signal with the digital telemetry signal, transmitter means for transmitting the pulse-modulated carrier signal therefrom, and means for coupling the pulse-modulated carrier signal onto the electrical lead, for radiation outwardly to external receiver means; and the external receiving means adapted to receive the pulse-modulated carrier signal transmitted by the coupling means.

Claim 10

A living tissue stimulator apparatus comprising: implantable stimulator means for selectively producing electrical stimulus signals for transmission to living tissue; an electrical lead adapted to carry the stimulus signals from the implantable stimulator means to the tissue; telemetry means mounted with the stimulator means for producing a telemetry signal and for transmitting the telemetry signal therefrom, the telemetry means including digital means for producing a digital telemetry signal, modulator means for pulse modulating a carrier signal with the digital telemetry signal, transmitter means for transmitting the pulse-modulated carrier signal therefrom, and means for coupling the pulse-modulated carrier signal onto the electrical lead, for radiation outwardly to external receiver means; and the external receiving means adapted to receive the pulse-modulated carrier signal transmitted by the coupling means.

Claim 11

A living tissue stimulator apparatus as defined in claim 8, wherein: the apparatus further includes a metallic case for housing the implantable stimulator means and telemetry means, and a second electrical lead adapted to carry the stimulus signals from the stimulator means to the tissue; and the telemetry means includes means for applying the telemetry signal between the two electrical leads and the case, to provide a dipole antenna.

Claim 12

A living tissue stimulator apparatus as defined in claim 8, wherein: the apparatus is a pacemaker and the tissue is a heart muscle; the apparatus further includes means for monitoring electrical signals generated by the heart muscle and for producing a corresponding analog electrocardiogram signal; the telemetry means includes analog-to-digital converter means for digitizing the analog electrocardiogram signal to produce the digital telemetry signal.

Claim 13

A living tissue stimulator apparatus as defined in claim 10, wherein the telemetry means further includes: memory means for storing digital data; and multiplexing means for multiplexing the digital data stored by the memory means with the digitized electrocardiogram signal provided by the analog-to-digital converter means to produce the digital telemetry signal.

Claim 14

A living tissue stimulator apparatus as defined in claim 10, wherein: the carrier signal modulated by the telemetry means has a frequency in the range of 10 to 300 megahertz.

Claim 15

A living tissue stimulator apparatus comprising: implantable stimulator means for selectively producing electrical stimulus signals for transmission to the tissue; telemetry means mounted with the stimulator means for producing a telemetry signal and for transmitting the telemetry signal therefrom, the telemetry means including digital means for producing a digital telemetry signal, wherein the digital telemetry signal includes a succession of bits, each having either a first state or a second state; modulator means for pulse modulating a carrier signal with the digital telemetry signal, the modulator means having means for providing a single burst of the carrier signal when a bit of the telemetry signal has the first state and an absence of the carrier signal when a bit has the second state; and transmitter means for transmitting the pulse-modulated carrier signal therefrom.

Claim 16

A living tissue stimulator apparatus comprising: implantable stimulator means for selectively producing electrical stimulus signals for transmission to the tissue; telemetry means mounted with the stimulator means for producing a telemetry signal and for transmitting the telemetry signal therefrom, the telemetry means including digital means for producing a digital telemetry signal, wherein the digital telemetry signal includes a succession of bits, each having either a first state or a second state; modulator means for pulse modulating a carrier signal with the digital telemetry signal, the modulator means having means for providing a single burst of the carrier signal when a bit of the telemetry signal has the first state and an absence of the carrier signal when a bit has the second state; and transmitter means for transmitting the pulse-modulated carrier signal therefrom.

Claim 17

A living tissue stimulator apparatus as defined in claim 13, wherein: the single burst of the carrier signal, provided by the modulator means when a bit of the telemetry signal has the first state, has a duty cycle of less than about 0.2; and the carrier signal modulated by the telemetry means has a frequency in the range of 10 to 300 megahertz.

Claim 20

A method as defined in claim 15 wherein: the implanted tissue stimulator further includes a metallic case and a second electrical lead for carrying the stimulus signals to the tissue; and the method further includes a step of applying the telemetry signal between the two electrical leads and the case, such that a dipole antenna configuration is provided.

Claim 23

A method as defined in claim 17, wherein: the implanted tissue stimulator is a pacemaker adapted to stimulate the heart muscle; the method further includes steps of monitoring electrical signals generated by the heart and producing a corresponding analog electrocardiogram signal; and the step of producing includes a step of digitizing the analog electrocardiogram signal to produce the digital telemetry signal.

Claim 24

A method as defined in claim 18, wherein the step of producing further includes steps of: storing digital data; and multiplexing the stored digital data with the digitized electrocardiogram signal to produce the digital telemetry signal.

Claim 25

A method as defined in claim 17, wherein: the digital telemetry signal includes a succession of bits, each having either a first state or a second state; and the step of modulating includes a step of providing a single burst of the carrier signal when a bit of the telemetry signal has the first state and an absence of the carrier signal when a bit has the second state.

Claim 26

A method as defined in claim 20, wherein: the single burst of the carrier signal provided in the step of modulating has a duty cycle of less than about 0.2; and the carrier signal modulated in the step of modulating has a frequency in the range of 10 to 300 megahertz.

Claim 27

A pacemaker for stimulating a heart comprising: implantable stimulator means for selectively producing electrical stimulus signals; first and second electrical leads adapted to carry the stimulus signals from the stimulator means to the heart; means for monitoring electrical signals generated by the heart and for producing a corresponding analog electrocardiogram signal; analog-to-digital converter means for digitizing the analog electrocardiogram signal to produce a digitized electrocardiogram signal; memory means of storing digital data; multiplexing means for multiplexing the digital data stored by the memory means with the digitized electrocardiogram signal provided by the analog-to-digital converter means, to produce a digital telemetry signal; modulator means for pulse-modulating a carrier signal with the digital telemetry signal; a metallic case for housing the implantable stimulator means, the means for monitoring, the analog-to-digital converter means, the memory means, the multiplexing means and the modulator means; and means for applying the pulse-modulated carrier signal between the first and second electrical leads and the case, to provide a dipole antenna for radiating the carrier signal outwardly.

Claim 28

A pacemaker for stimulating a heart comprising: implantable stimulator means for selectively producing electrical stimulus signals; first and second electrical leads adapted to carry the stimulus signals from the stimulator means to the heart; means for monitoring electrical signals generated by the heart and for producing a corresponding analog electrocardiogram signal; analog-to-digital converter means for digitizing the analog electrocardiogram signal to produce a digitized electrocardiogram signal; memory means of storing digital data; multiplexing means for multiplexing the digital data stored by the memory means with the digitized electrocardiogram signal provided by the analog-to-digital converter means, to produce a digital telemetry signal; modulator means for pulse-modulating a carrier signal with the digital telemetry signal; a metallic case for housing the implantable stimulator means, the means for monitoring, the analog-to-digital converter means, the memory means, the multiplexing means and the modulator means; and means for applying the pulse-modulated carrier signal between the first and second electrical leads and the case, to provide a dipole antenna for radiating the carrier signal outwardly.

Claim 29

A heart pacemaker as defined in claim 22 wherein: the digital telemetry signal includes a succession of bits, having either a first state or a second state; the modulator means includes means for providing a single burst of the carrier signal when a bit of the telemetry signal has the first state and an absence of the carrier signal when a bit has the second state; the single burst of the carrier signal, provided by the modulator means when a bit of the telemetry signal has the first state, has a duty cycle of less than about 0.2; and the carrier signal modulated by the modulator means has a frequency in the range of 10 to 300 megahertz.