Implantable cardiac patient monitor

Claim 2

A cardiac monitor as defined in claim 1 further characterized in that the processing means is further responsive to the electrocardiograms for detecting ischemia of the heart.

Claim 3

A cardiac monitor as defined in claim 2 further characterized in that the selected ones of said electrocardiograms are stored in said memory means and that said processing means is responsive to the stored selected electrocardiograms for detecting ischemia of the heart.

Claim 4

A cardiac monitor as defined in claim 2 further characterized in that the processing means is programmable for detecting only the arrhythmias, for detecting only the ischemia, or for detecting both the arrhythmias and the ischemia.

Claim 5

A cardiac monitor as defined in claim 4 further characterized by programming means (100) implantable beneath the skin of a patient for programming the processing means, the programming means receiving program commands from external to the patient for programming the processing means.

Claim 6

A cardiac monitor as defined in claim 5 further characterized in that the memory means stores a first set of operating instructions to cause the processing means to detect the arrhythmias and a second set of operating instructions to cause the processing means to detect the ischemia, and wherein the processing means obtains from the memory means only the first set of operating instructions, only the second set of operating instructions, or both the first and second sets of operating instructions responsive to the programming means.

Claim 7

A cardiac monitor as defined in claim 1 further characterized in that the processing means is responsive to the electrocardiograms for discriminating between normal sinus heart beats and abnormal heart beats.

Claim 8

A cardiac monitor as defined in claim 7 further characterized in that the abnormal beats are ventricular beats.

Claim 9

A cardiac monitor as defined in claim 7 further characterized in that the memory means stores a template (120) representing a normal sinus heart beat and wherein the processing means compares each electrocardiogram to the template to discriminate between the normal sinus heart beats and the abnormal heart beats.

Claim 10

A cardiac monitor as defined in claim 9 further characterized in that the template includes a QRS portion, wherein the electrocardiograms include a QRS portion, and wherein the processing means compares the QRS portions of the electrocardiograms to the QRS portion of the template.

Claim 11

A cardiac monitor as defined in claim 9 further characterized in that the processing means revises the template stored in the memory means at spaced apart time intervals in response to the electrocardiograms generated over the last time interval.

Claim 12

A cardiac monitor as defined in claim 2 further characterized in that the processing means is responsive to the electrocardiograms for discriminating between normal sinus heart beats and abnormal heart beats, and the processing means detects for the ischemia responsive to only electrocardiograms representing normal sinus heart beats.

Claim 13

A cardiac monitor as defined in claim 1 further characterized in that the processing means is responsive to the electrocardiograms for determining the heart rate of the heart for each heart beat.

Claim 14

A cardiac monitor as defined in claim 13 further characterized in that the processing means stores the last given number of heart rates in the memory means and computes, after each heart beat, an average heart rate based upon the last given number of heart rates.

Claim 15

A cardiac monitor as defined in claim 7 further characterized in that the processing means is responsive to a sequence of the normal sinus heart beats and the abnormal heart beats for determining a rhythm of the heart.

Claim 16

A cardiac monitor as defined in claim 15 further characterized in that the processing means is responsive to a selected sequence for detecting ventricular tachycardia of the heart.

Claim 17

A cardiac monitor as defined in claim 16 further characterized in that the electrocardiograms of the selected sequence corresponding to at least the onset and termination of the ventricular tachycardia are stored in the memory means.

Claim 18

A cardiac monitor as defined in claim 2 further characterized in that the processing means is responsive to selected ones of the electrocardiograms for detecting ischemia of the heart.

Claim 19

A cardiac monitor as defined in claim 18 further characterized in that the electrocardiograms include ST segments and wherein the processing means determines if the levels of the ST segments of the selected electrocardiograms are above a predetermined threshold level for detecting ischemia of the heart.

Claim 20

A cardiac monitor as defined in claim 18 further characterized in that the processing means generates and stores in the memory means ischemia data upon detecting each ischemia.

Claim 21

A cardiac monitor as defined in claim 20 further characterized in that the processing means retains in the memory means the ischemia data for each ischemia episode and that the telemetry means transmit the retained ischemia data.

Claim 22

A cardiac monitor as defined in claim 1 further characterized in that the electrode means (34,36) include first and second electrodes (408,414; 520,524; 564,570), the sensing means being coupled to the first and second electrodes for generating first and second respective electrocardiograms of each heart beat of the heart, and the processing means being responsive to the first and second electrocardiograms for detecting arrhythmias of the heart and generating arrhythmia data characterizing the arrhythmias.

Claim 23

A cardiac monitor as defined in claim 22 further characterized in that the electrode means include third and fourth electrodes (410,416; 522,526; 566,572) for establishing electrical contact with the heart to detect heart beats of the heart, the sensing means being coupled to the third and fourth electrodes for generating third and fourth respective electrocardiograms of each heart beat of the heart, and the processing means being responsive to the first, second, third, and fourth electrocardiograms for detecting ischemia and generating ischemia data characterizing the ischemia.

Claim 24

A cardiac monitor as defined in claim 22 further characterized in that the first and second electrodes are subcutaneous electrodes.

Claim 25

A cardiac monitor as defined in claim 23 further characterized in that the third and fourth electrodes are subcutaneous electrodes.

Claim 26

A cardiac monitor for monitoring the physiology of a human heart, the monitor being fully implantable beneath the skin of a patient, the cardiac monitor characterized by: electrode means (34,36) for establishing electrical contact with the heart; sensing means (56) coupled to the electrode means for generating an electrocardiogram of each heart beat of the heart; data generating means (40) coupled to the sensing means for generating electrocardiogram data for each generated electrocardiogram; processing means (90) responsive to the electrocardiograms corresponding to natural heart beats for processing the electrocardiogram data to generate characterizing data indicative of the physiology of the heart; and memory means (82) coupled to the data generating means and to the processing means for storing the electrocardiogram data and the characterizing data, the processing means obtaining the electrocardiogram data from the memory means and processing the electrocardiogram data at times in between the heart beats.

Claim 27

A cardiac monitor as defined in claim 26 further characterized in that direct memory access means (88) couple the memory means to the data generating means and to the processing means for providing the memory means with the generated electrocardiogram data.

Claim 28

A cardiac monitor as defined in claim 27 further characterized in that the characterizing data includes arrhythmia data and/or ischemia data.

Claim 29

A cardiac monitor as defined in claim 28 further characterized in that the processing means is responsive to the electrocardiogram data for discriminating between normal sinus heart beats and ventricular beats of the heart and the processing means generates the ischemia data for normal sinus heart beats.

Claim 30

An electrode system for use with a fully implantable cardiac monitor (30) including electrical circuitry for monitoring the physiology of the human heart and having an enclosure (32) for containing the electrical circuitry, the enclosure including an upper perimeter, the electrode system characterized by: an electrically insulating header assembly (402; 504) sealingly engaged with the upper perimeter (400;506) of the enclosure; first and second flexible insulative conduits (404,406; 516,518) extending from the header; first and second electrode means (34,36) carried by each of the first and second conduits respectively, the first and second electrode means each including at least one electrically conductive electrode (408,414; 520,524); and conductor means (420,422; 532,534,536,538) extending through the first and second conduits and into the header for coupling the electrodes of the first and second electrode means to the electrical circuitry of the monitor, the conduits and the electrode means being implantable beneath the skin of a patient to dispose the electrodes in non-touching proximity to the heart for establishing electrical contact between the electrodes and the heart.

Claim 31

An electrode system as defined in claim 30 further characterized in that the first and second electrode means each include three spaced apart electrically conductive electrodes (408,410,412; 414,416,418).

Claim 32

An electrode system as defined in claim 30 further characterized in that the first and second electrode means each include two spaced apart electrically conductive electrodes (448,450; 452,454).

Claim 33

An electrode system as defined in claim 32 further characterized in that each of the flexible conduits has a diameter and the first and second electrode means include catheter electrode means each including at least one ring-shaped electrode.

Claim 34

An electrode system as defined in claim 33 further characterized in that the first and second electrode means each include two spaced apart ring-shaped electrodes.

Claim 35

An electrode system as defined in claim 33 further characterized in that the first and second electrode means each include three spaced apart conductive ring-shaped electrodes.

Claim 36

An electrode system as defined in claims 30 or 34 further characterized in that the enclosure includes an electrically conductive surface portion (466; 550) for providing a ground reference for the electrodes.

Claim 37

An electrode system as defined in claims 30, 31, 32, 33, 34, or 35 further characterized in that the first and second conduits extend from the header in a substantially V-shaped configuration.

Claim 38

An electrode system as defined in claim 30 further characterized in that the header includes first and second connector receptacles (438,440; 472,474; 508,510), the first and second conduits (444,446; 476,478; 516,518) each include a connector (460,642; 494,498; 512,510), the first connector receptacle being configured to receive the connector of the first conduit and the second connector receptacle being configured to receive the-connector of the second conduit.

Claim 39

An electrode system as defined in claim 38 further characterized in that the first and second connector receptacles are disposed in opposing relation.

Claim 40

An electrode system as defined in claim 30 further characterized in that the first and second connector receptacles (576,578) are disposed in non-opposing relation.

Claim 41

An electrode system as defined in claim 30 further characterized in that the first and second conduits each include suture means (500,5102; 540,542) between the header and the electrode means to permit the conduits to be sutured in place during implantation.

Claim 42

An electrode system as defined in claim 41 further characterized in that the conduit means (516,518; 582,584) are of a length to enable the conduit means to be looped around the enclosure to provide strain relief for the conduit means between the suture means and the header.

Claim 43

An electrode system as defined in claim 30 further characterized in that a plurality of spaced apart fixation projections (560) project from each electrode means.

Claim 44

A cardiac monitor for monitoring the physiology of the human heart, the monitor being fully implantable beneath the skin of a patient and characterized by: a hermetically sealed enclosure (32), the enclosure defining a cavity having an opened perimeter (600), and a header (602) sealingly engaging the perimeter; first and second electrical conductors (604,606) covering first and second respective discrete portions of the enclosure for forming first and second sensing electrodes respectively for sensing activity of the heart; a third electrical conductor (608) covering a third discrete portion of the enclosure for forming a reference electrode; and circuit means within the enclosure and coupled to the electrodes for monitoring the activity of the heart sensed by the sensing electrodes.

Claim 45

A cardiac monitor as defined in claim 44 further characterized in that the third electrical conductor (608) is equally spaced from the first and second conductors (604,606).

Claim 46

A cardiac monitor as defined in claim 44 further characterized in that the header is formed from electrically insulating material and the first and second electrical conductors are formed by an electrically conductive coating covering the discrete portions of the header.

Claim 47

A cardiac monitor as defined in claim 46 further characterized in that the header is a first header (602), and the enclosure includes a second header (610) formed from electrically insulating material, the second header being opposite the first header.

Claim 48

A cardiac monitor as defined in claim 47 further characterized in that the circuit means generates data indicative of the monitored activity of the heart, the monitor further includes telemetry means (116) for transmitting the data to a non-implanted external receiver, and the telemetry means is disposed in the second header.