Apparatus for discrimination of stable and unstable ventricular tachycardia and for treatment thereof

Claim 2

A cardioverter, comprising: therapy means for delivering a first therapy for termination of stable tachyarrhythmias and a second therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the hemoglobin of the venous return blood in said patient's heart; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation; discriminator means responsive to said detection means, said sensor means and said reference means for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation and for triggering said therapy means to deliver said second therapy in response to the detection of said unstable tachyarrhythmia.

Claim 3

A cardioverter according to claim 1 wherein said means for measuring the current level of oxygen saturation comprises means for taking a plurality of individual oxygen saturation measurements and for defining said current level of oxygen saturation as an average of a plurality of said individual oxygen saturation measurements and said reference means comprises means for defining and storing an average of a plurality of said individual oxygen saturation measurements.

Claim 4

A cardioverter according to claim 2 wherein said reference means comprises means for detecting that said patient is in a resting state and wherein said reference means comprises means for deriving and storing said reference level of oxygen saturation as an average of said individual oxygen saturation measurements taken while said patient is in said detected resting state.

Claim 5

A cardioverter according to claim 3 wherein said means for detecting that said patient is in a resting state comprises means responsive to said for sensing the rhythm of said patient's heart and for identifying the sensed rhythm of said patient's heart as indicative of a resting state.

Claim 6

A cardioverter according to claim 4 wherein said means for detecting that said patient is in a resting state comprises means responsive to the heart rhythm sensed by said means for sensing the rhythm of said patient's heart and for identifying the sensed rhythm of said patient's heart as indicative of a resting state.

Claim 7

A cardioverter, comprising: therapy means for delivering a first therapy for termination of stable tachyarrhythmias and a second therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount and for triggering said therapy means to deliver said second therapy in response to the detection of said unstable tachyarrhythmia.

Claim 8

A cardioverter, comprising: therapy means for delivering a first therapy for termination of stable tachyarrhythmias and a second therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount and for triggering said therapy means to deliver said second therapy in response to the detection of said unstable tachyarrhythmia.

Claim 9

A cardioverter according to claim 6 wherein said means for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level comprises means for taking a plurality of individual oxygen saturation pulse amplitude measurements and for deriving said amplitude of said current pulsatile character of said oxygen saturation level as an average of a plurality of said individual oxygen saturation pulse amplitude measurements and said reference means comprises means for defining said reference oxygen saturation pulse amplitude means comprises means for deriving and storing an average taken over a plurality of said individual oxygen saturation pulse amplitude measurements.

Claim 10

A cardioverter according to claim 7 wherein said reference means comprises means for detecting that said patient is in a resting state and wherein said reference means comprises means for deriving and storing an average of said oxygen saturation pulse amplitude measurements taken while said patient is in said detected resting state.

Claim 11

A cardioverter, comprising: therapy means for delivering a first therapy for termination of stable tachyarrhythmias and a second therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation and for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means, to the difference between said measured current level of oxygen saturation and said reference level of oxygen saturation and to the difference between said measured current amplitude of the pulsatile character of the level of oxygen saturation and said reference oxygen saturation pulse amplitude and for triggering said therapy means to deliver said second therapy in response to the detection of said unstable tachyarrhythmia.

Claim 12

A cardioverter, comprising: therapy means for delivering a first therapy for termination of stable tachyarrhythmias and a second therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation and for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means, to the difference between said measured current level of oxygen saturation and said reference level of oxygen saturation and to the difference between said measured current amplitude of the pulsatile character of the level of oxygen saturation and said reference oxygen saturation pulse amplitude and for triggering said therapy means to deliver said second therapy in response to the detection of said unstable tachyarrhythmia.

Claim 13

A cardioverter according to claim 9 wherein said discriminator means comprises means for detecting the presence of said unstable tachyarrhythmia in response to a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount in conjunction with a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation.

Claim 14

A cardioverter according to claim 9 wherein said discriminator means comprises means for detecting the presence of said unstable tachyarrhythmia in response to a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount or in response to a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation.

Claim 15

A cardioverter according to claim 1 or claim 6 or claim 9 wherein said discriminator means further comprises means for triggering said therapy means to deliver said second therapy in response to the detection of a tachyarrhythmia by said detector means in the absence of detection of an unstable tachyarrhythmia by said discriminator means.

Claim 16

A cardioverter according to claim 12 wherein said means for providing said first therapy comprises means for delivering a defibrillation pulse to said patient's heart.

Claim 17

A cardioverter according to claim 13 wherein said means for providing said second therapy comprises means for delivering of an electrical pulse of less amplitude than said defibrillation pulse to said patient's heart.

Claim 18

A cardioverter according to claim 14 wherein said means for providing said second therapy comprises means for delivering a cardioversion pulse.

Claim 19

A cardioverter according to claim 14 wherein said means for providing said second therapy comprises means for delivering a cardiac pacing pulse.

Claim 20

A cardioverter, comprising: therapy means for delivering a therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patient's heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the venous return blood in said patient's heart; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation and for triggering said therapy means to deliver said therapy in response to the detection of said unstable tachyarrhythmia.

Claim 21

A cardioverter, comprising: therapy means for delivering a therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patient's heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the venous return blood in said patient's heart; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation and for triggering said therapy means to deliver said therapy in response to the detection of said unstable tachyarrhythmia.

Claim 22

A cardioverter, comprising: therapy means for delivering a therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount and for triggering said therapy means to deliver said therapy in response to the detection of said unstable tachyarrhythmia.

Claim 23

A cardioverter, comprising: therapy means for delivering a therapy for termination of unstable tachyarrhythmias to a patient's heart; detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount and for triggering said therapy means to deliver said therapy in response to the detection of said unstable tachyarrhythmia.

Claim 24

A discriminator, comprising: detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the hemoglobin of the venous return blood in said patient's heart; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation.

Claim 25

A discriminator, comprising: detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the current level of oxygen saturation of the hemoglobin of the venous return blood in said patient's heart; reference means responsive to said sensor for storing a measured level of oxygen saturation as a reference level of oxygen saturation; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current level of oxygen saturation which varies less than a predetermined amount from said reference level of oxygen saturation.

Claim 26

A discriminator, comprising: detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount.

Claim 27

A discriminator, comprising: detection means for sensing the rhythm of said patients heart and for detecting the presence of a tachyarrhythmia; an oxygen saturation sensor means for measuring the oxygen saturation level of the hemoglobin of the venous return blood in said patient's heart and for deriving a measurement of the amplitude of the current pulsatile character of the measured oxygen saturation level; reference means responsive to said sensor for storing a measurement of the amplitude of the pulsatile character of the level of oxygen saturation as a reference oxygen saturation pulse amplitude; discriminator means responsive to said detection means, said sensor means and said reference means, for detecting the presence of an unstable tachyarrhythmia in response to the detection of a tachyarrhythmia by said detecting means and a measured current amplitude of the pulsatile character of the level of oxygen saturation which is less than said reference oxygen saturation pulse amplitude by a predetermined amount.