Apparatus and method for detecting abnormal cardiac rhythms using evoked potential measurements in an arrhythmia control system

Claim 2

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, and means responsive to said detecting means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles.

Claim 3

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 1, wherein said arrhythmia detection control parameter is a paced depolarization integral, said pathological tachycardia is characterized generally by an increasing paced depolarization integral, and said benign physiological tachycardia is characterized generally by a paced depolarization integral which decreases or remains unchanged.

Claim 4

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 1, further comprising means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in an antitachycardia pacing mode.

Claim 5

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means responsive to said detecting means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles, and means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in a dual-chamber antitachycardia pacing mode in which atrial and ventricular pacing pulses are generated and delivered in a series of pulse trains with each train consisting of a series of pacing pulses delivered in rapid succession in an alternating sequence to the ventricle and to the atrium.

Claim 6

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means responsive to said detecting means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles, and means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in a dual-chamber antitachycardia pacing mode in which atrial and ventricular pacing pulses are generated and delivered in a series of pulse trains with each train consisting of a series of pacing pulses delivered in rapid succession in an alternating sequence to the ventricle and to the atrium.

Claim 7

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means responsive to said detecting means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles, means responsive to said detecting means for measuring short-term uniformity of said arrhythmia detection control parameter, and means for classifying a cardiac rhythm as fibrillation when said arrhythmia detection control parameter changes in a third predetermined direction and magnitude within a predetermined number of cardiac cycles and said short-term uniformity measurement changes in a fourth predetermined directions and magnitude within a predetermined number of cardiac cycles,

Claim 8

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means responsive to said detecting means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles, means responsive to said detecting means for measuring short-term uniformity of said arrhythmia detection control parameter, and means for classifying a cardiac rhythm as fibrillation when said arrhythmia detection control parameter changes in a third predetermined direction and magnitude within a predetermined number of cardiac cycles and said short-term uniformity measurement changes in a fourth predetermined directions and magnitude within a predetermined number of cardiac cycles,

Claim 9

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 5, wherein said arrhythmia detection control parameter is a paced depolarization integral and said fibrillation is characterized in general by a decreasing paced depolarization integral occurring simultaneously with a decreasing short-term uniformity of paced depolarization time samples.

Claim 10

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 5, further comprising: means for generating defibrillation shocks; and means responsive to the classification of a cardiac rhythm as fibrillation by said classifying means for controlling said defibrillation generating means to generate shocks.

Claim 11

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, and means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate.

Claim 12

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, and means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate.

Claim 13

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 8, wherein said arrhythmia detection control parameter is a paced depolarization integral, said pathological tachycardia is characterized generally by an increasing paced depolarization integral, and said benign physiological tachycardia is characterized generally by a paced depolarization integral which decreases or remains unchanged.

Claim 14

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 8, further comprising means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in an antitachycardia pacing mode.

Claim 15

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate, and means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in an antitachycardia pacing mode, wherein said antiarrhythmia pacing device operates in a dual-chamber antitachycardia pacing mode in which atrial and ventricular pacing pulses are generated and delivered in a series of pulse trains with each train consisting of a series of pacing pulses delivered in rapid succession in an alternating sequence to the ventricle and to the atrium.

Claim 16

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate, and means responsive to classification of the cardiac rhythm as a pathological tachycardia by said classifying means for controlling said generating means to operate in an antitachycardia pacing mode, wherein said antiarrhythmia pacing device operates in a dual-chamber antitachycardia pacing mode in which atrial and ventricular pacing pulses are generated and delivered in a series of pulse trains with each train consisting of a series of pacing pulses delivered in rapid succession in an alternating sequence to the ventricle and to the atrium.

Claim 17

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate, means responsive to said detecting means for measuring short-term uniformity of said arrhythmia detection control parameter, and means for classifying a cardiac rhythm as fibrillation when said heart rate is faster than a predetermined fibrillation rate, said arrhythmia detection control parameter changes in a third predetermined direction and magnitude within a predetermined number of cardiac cycles, and said short-term uniformity measurement changes in a fourth predetermined direction and magnitude within a predetermined number of cardiac cycles.

Claim 18

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as a pathological tachycardia when said arrhythmia detection control parameter changes in a first predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than a predetermined tachycardia rate, and for classifying a cardiac rhythm as a benign physiological tachycardia when said arrhythmia detection control parameter changes in a second predetermined direction and magnitude within a predetermined number of cardiac cycles and said heart rate is faster than said tachycardia rate, means responsive to said detecting means for measuring short-term uniformity of said arrhythmia detection control parameter, and means for classifying a cardiac rhythm as fibrillation when said heart rate is faster than a predetermined fibrillation rate, said arrhythmia detection control parameter changes in a third predetermined direction and magnitude within a predetermined number of cardiac cycles, and said short-term uniformity measurement changes in a fourth predetermined direction and magnitude within a predetermined number of cardiac cycles.

Claim 19

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 12, wherein said arrhythmia control parameter is a paced depolarization integral and said fibrillation is characterized in general by a decreasing paced depolarization integral occurring simultaneously with a decreasing short-term uniformity of paced depolarization time samples.

Claim 20

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 12, further comprising: means for generating defibrillation shocks and means responsive to the classification of a cardiac rhythm as fibrillation by said classifying means for controlling said defibrillation generating means to generate shocks.

Claim 23

A method of detecting and reverting cardiac arrhythmias in accordance with claim 15, wherein said arrhythmia detection control parameter is a paced depolarization integral, said pathological tachycardia is characterized generally by an increasing paced depolarization integral, and said benign physiological tachycardia is characterized generally by a paced depolarization integral which decreases or remains unchanged.

Claim 24

A method of detecting and reverting cardiac arrhythmias in accordance with claim 15, further comprising the step of controlling said generating means to operate in an antitachycardia pacing mode in response to classifying a cardiac rhythm as a pathological tachycardia.

Claim 29

A method of detecting and reverting cardiac arrhythmias in accordance with claim 19, wherein said arrhythmia control parameter is a paced depolarization integral and said fibrillation is characterized in general by a decreasing paced depolarization integral occurring simultaneously with a decreasing short-term uniformity of paced depolarization time samples.

Claim 30

A method of detecting and reverting cardiac arrhythmias in accordance with claim 19, further comprising the steps of: generating defibrillation shocks; and controlling said defibrillation generating step to generate shocks in response to classification of a cardiac rhythm as fibrillation in said classifying step.

Claim 33

A method of detecting and reverting cardiac arrhythmias in accordance with claim 22, wherein said arrhythmia detection control parameter is a paced depolarization integral, said pathological tachycardia is characterized generally by an increasing paced depolarization integral, and said benign physiological tachycardia is characterized generally by a paced depolarization integral which decreases or remains unchanged.

Claim 34

A method of detecting and reverting cardiac arrhythmias in accordance with claim 22, further comprising the step of controlling said generating means to operating in an antitachycardia pacing mode in response to classifying a cardiac rhythm as a pathological tachycardia.

Claim 39

A method of detecting and reverting cardiac arrhythmias in accordance with claim 26, wherein said arrhythmia detection control parameter is a paced depolarization integral and said fibrillation is characterized in general by a decreasing paced depolarization integral occurring simultaneously with a decreasing short-term uniformity of paced depolarization time samples.

Claim 40

A method of detecting and reverting cardiac arrhythmias in accordance with claim 26, further comprising the steps of: generating defibrillation shocks; and controlling said defibrillation generating step to generate shocks in response to classification of a cardiac rhythm as fibrillation in said classifying step.

Claim 41

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, and means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as asystole when said heart rate is slower than a predetermined bradycardia rate and said arrhythmia detection control parameter remains essentially unchanged within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as fibrillation when said heart rate is slower than a predetermined bradycardia rate and said arrhythmia detection control parameter changes in a predetermined direction and magnitude within a predetermined number of cardiac cycles.

Claim 42

An arrhythmia detection and antiarrhythmia pacing device adapted to be implanted in a patient for the reversion of tachycardias, comprising: means for generating heart stimulation pulses, means for measuring an evoked potential of the patient's heart that is responsive to said stimulation pulses, means based upon the sensing of an evoked potential for periodically ascertaining the value of a measured arrhythmia detection control parameter, means for detecting changes over time in said measured arrhythmia detection control parameter, means for sensing heartbeats, means responsive to said heartbeat sensing means for determining a heart rate, and means responsive to said detecting means and said heart rate determining means for classifying a cardiac rhythm as asystole when said heart rate is slower than a predetermined bradycardia rate and said arrhythmia detection control parameter remains essentially unchanged within a predetermined number of cardiac cycles, and for classifying a cardiac rhythm as fibrillation when said heart rate is slower than a predetermined bradycardia rate and said arrhythmia detection control parameter changes in a predetermined direction and magnitude within a predetermined number of cardiac cycles.

Claim 43

An arrhythmia detection and antiarrhythmia pacing device in accordance with claim 29, wherein said arrhythmia control parameter is a paced depolarization integral and said asystole is characterized in general by an essentially unchanging paced depolarization integral and said fibrillation is characterized in general by a reduced paced depolarization integral.