Implantable cardiac stimulating apparatus and method employing detection of P-waves from signals sensed in the ventricle

Claim 2

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical energy in such tissue and detecting therefrom the occurrence of P-waves; and control means, having timing means therein, for controlling said generating and transmitting means to provide a stimulation pulse to said second electrode for provision to the tissue of the ventricle, in response to said sensing means detecting the occurrence of a P-wave in the intrinsic electrical activity in the tissue of the patient's ventricle.

Claim 3

An apparatus according to claim 1, further including a bipolar pacing leading having tip and ring electrodes, and wherein: said first and second electrodes each comprise a separate one of the tip and ring electrodes of said bipolar pacing lead.

Claim 4

An apparatus according to claim 1, wherein: said apparatus includes an external case, nd said first electrode in the external case of said apparatus.

Claim 5

An apparatus according to claim 1, wherein: said timing means times a predetermined delay following the detection of an occurrence of a P-wave and then enables said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.

Claim 6

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate.

Claim 7

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate.

Claim 8

An apparatus according to claim 5, wherein: said sensing and detecting means further comprises: means for producing a time sequence of waveform segment template samples characterizing a P-wave; means for receiving and for storing waveform segment templates which are representative of P-wave waveforms; means for producing a time sequence of intrinsic cardiac electrical unknown signal samples from said time sequence of waveform segment template samples to derive a template matching coefficient; means for receiving and storing predetermined threshold criteria; means for comparing said derived template matching coefficient with said threshold criteria; and means for classifying said unknown signal samples as a P-wave when said template matching coefficient exceeds said threshold criteria.

Claim 9

An apparatus according to claim 6, wherein: said timing means times a predetermined delay following the detection of an occurrence of a P-wave and then enables said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.

Claim 10

An apparatus according to claim 6, further including a bipolar pacing leading having tip and ring electrodes therein, and wherein: said first and second electrodes each comprise a separate one of the tip and ring electrodes of said bipolar pacing lead.

Claim 11

An apparatus according to claim 6 wherein: said matching means derives said template matching coefficient by performing a template matching operation selected from a group of operations consisting of: determining an area of difference, determining a mean area of difference, determining a normalized mean area of difference, determining a correlation coefficient, determining a bin area coefficient, and determining a least mean square adaptive coefficient.

Claim 14

A method according to claim 10, wherein: said step of deriving pulse generation control signals comprises the substeps of: sensing intrinsic ventricular electrical signals following the occurrence of a P-wave in the atrium of the patient's heart; characterizing and storing said ventricular electrical signals sensed following the occurrence of a P-wave in a time sequence of template samples; subsequently monitoring a time sequence of intrinsic ventricular electrical signal samples when intrinsic atrial electrical activity is unknown; matching said monitored sample with said stored template samples to derive a template matching coefficient; providing a template matching coefficient threshold value; comparing said template matching coefficient with said threshold value; and classifying said monitored sample as a P-wave when said template matching coefficient is greater than said threshold value.

Claim 15

A method according to claim 11, wherein: upon the classifying of said monitored samples as a P-wave, enabling a predetermined delay, and thereafter enabling said pulse generation step.

Claim 16

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves, said sensing and detecting means further comprising: means for producing a time sequence of waveform segment template samples characterizing a P-wave, means for receiving and for storing waveform segment templates which are representative a P-wave waveforms, means for producing a time sequence of intrinsic cardiac electrical unknown signal samples from said second electrode, means for matching said unknown signal samples to said time sequence of waveform segment template samples to derive a template matching coefficient, means for receiving and storing predetermined threshold criteria, means for comparing said derived template matching coefficient with said threshold criteria, and means for classifying said unknown signal samples as a P-wave when said template matching coefficient exceeds said threshold criteria, said apparatus further comprising: control means, having timing means therein, for controlling said generating and transmitting means to provide a stimulation pulse to said second electrode for provision to the tissue of the ventricle, in response to said sensing means detecting the occurrence of a P-wave in the intrinsic electrical activity in the tissue of the patient's ventricle.

Claim 17

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves, said sensing and detecting means further comprising: means for producing a time sequence of waveform segment template samples characterizing a P-wave, means for receiving and for storing waveform segment templates which are representative a P-wave waveforms, means for producing a time sequence of intrinsic cardiac electrical unknown signal samples from said second electrode, means for matching said unknown signal samples to said time sequence of waveform segment template samples to derive a template matching coefficient, means for receiving and storing predetermined threshold criteria, means for comparing said derived template matching coefficient with said threshold criteria, and means for classifying said unknown signal samples as a P-wave when said template matching coefficient exceeds said threshold criteria, said apparatus further comprising: control means, having timing means therein, for controlling said generating and transmitting means to provide a stimulation pulse to said second electrode for provision to the tissue of the ventricle, in response to said sensing means detecting the occurrence of a P-wave in the intrinsic electrical activity in the tissue of the patient's ventricle.

Claim 18

An apparatus according to claim 12, wherein: said matching means derives said template matching coefficient by performing a template matching operation selected from a group of operations consisting of: determining an area of difference, determining a mean area of difference, determining a normalized mean area of difference, determining a correlation coefficient, determining a bin area coefficient, and determining a least mean square adaptive coefficient.

Claim 19

An apparatus according to claim 13, wherein: said timing means times a predetermined delay following the detection of an occurrence of a P-wave and then enables said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.

Claim 20

An apparatus according to claim 13, further including a bipolar pacing leading having tip and ring electrodes, and wherein: said first and second electrodes each comprise a separate one of the tip and ring electrodes of said bipolar pacing lead.

Claim 21

An apparatus according to claim 16, wherein: said matching means derives said template matching coefficient by performing a template matching operation selected from a group of operations consisting of: determining an area of difference, determining a mean area of difference, determining a normalized mean area of difference, determining a correlation coefficient, determining a bin area coefficient, and determining a least mean square adaptive coefficient.

Claim 22

An apparatus according to claim 16, wherein: said timing means times a predetermined delay following the detection of an occurrence of a P-wave and then enables said control means to control said generating an transmitting means to provide a stimulation pulse to said second electrode.

Claim 23

A cardiac stimulating apparatus for implantation in a patient, comprising: a bipolar pacing lead having tip and ring electrodes therein; a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; a first and second electrode each comprising a separate one of the tip and ring electrodes of said bipolar pacing lead; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate.

Claim 24

A cardiac stimulating apparatus for implantation in a patient, comprising: a bipolar pacing lead having tip and ring electrodes therein; a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; a first and second electrode each comprising a separate one of the tip and ring electrodes of said bipolar pacing lead; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate.

Claim 25

An apparatus according to claim 19, wherein: said timing means times a predetermined delay following the detection of an occurrence of a P-wave and then enables said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.

Claim 26

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate, said timing means timing a predetermined delay following the detection of an occurrence of a P-wave and then enabling said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.

Claim 27

A cardiac stimulating apparatus for implantation in a patient, comprising: a first electrode for implantation in the patient's body other than in the patient's atrium; a second electrode for implantation in the patient's ventricle and adapted for interengagement and electrical coupling with tissue of the patient's ventricle; means, coupled to said electrodes, for generating and transmitting stimulation pulses through said second electrode to the tissue of the ventricle; means, coupled to said electrodes, for sensing from the tissue of the patient's ventricle intrinsic cardiac electrical activity in such tissue and detecting therefrom the occurrence of P-waves; means responsive to said intrinsic cardiac activity sensing means for deriving an indication of an intrinsic atrial heartbeat rate; means for establishing a predetermined maximum atrial heartbeat rate; means for determining a metabolic indicator heartbeat rate; means for comparing said indication of intrinsic atrial heartbeat rate to said predetermined maximum atrial heartbeat rate and to said metabolic indicator rate; and control means responsive to said comparing means and including timing means therein for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on the timing of the occurrence of at least one P-wave when said intrinsic atrial heartbeat rate indication is slower than said predetermined maximum atrial heartbeat rate, and for controlling said generating and transmitting means to stimulate any electrically coupled ventricle tissue based on said metabolic indicator heartbeat rate when said intrinsic atrial heartbeat rate exceeds said predetermined maximum atrial heartbeat rate, said timing means timing a predetermined delay following the detection of an occurrence of a P-wave and then enabling said control means to control said generating and transmitting means to provide a stimulation pulse to said second electrode.