Method and apparatus for classifying and treating cardiac arrhythmias based on atrial and ventricular activity
First Claim
1. A method for classifying cardiac arrhythmias comprising the steps of:
- sensing the electrical activity of an atrium and a ventricle of the heart;
determining the ventricular rate of contraction and the atrial rate of contraction;
comparing the ventricular rate with a preset threshold value;
comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; and
classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate.
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Accused Products
Abstract
A method for classifying cardiac arrhythmias by examining the atrial and ventricular activity of the heart. The atrial contraction rate and ventricular contraction rate are compared with each other when the ventricular rate exceeds a preset value. When the atrial rate exceeds the ventricular rate, the regularity of the atrial rate, ventricular rate, and time interval between atrial contraction and ventricular contraction are determined. Regularity is determined by computing the standard deviation of a variable and comparing the standard deviation with a predetermined fractional value of the variable. A therapy routine is provided depending on the classification of a detected arrhythmia and the level of the ventricular contraction rate.
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Citations
30 Claims
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1. A method for classifying cardiac arrhythmias comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; and classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for classifying cardiac arrhythmias and delivering therapy to the heart comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; computing the time interval between atrial contraction and ventricular contraction (AV); comparing said AV time interval with a predetermined time interval value if said atrial rate is equal to said ventricular rate; classifying the rhythm of the heart as a junctional tachycardia if said ventricular and atrial rates are equal and said AV time interval is less than or equal to said predetermined time interval value; providing a lower rate limit of a first rate zone and a lower rate limit of a second rate zone, said lower rate limit of said second rate zone being greater than said lower rate limit of said first rate zone; providing a lower rate limit of a third rate zone being greater than said lower rate limit of said second rate zone; comparing said ventricular contraction rate with said lower rate limit of said third rate zone if said ventircular contraction rate is greater than said atrial contraction rate to determine if the rhythm of the heart is ventricular fibrillation; comparing said ventricular contraction rate with said lower rate limit of said second rate zone if said ventricular rate is less than said lower rate limit of said third rate zone to determine if the heart is in a fast rhythm or an arrhythmia requiring a cardioverting shock; delivering defibrillation pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said third rate zone; delivering cardioverting pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said second rate zone and less than said lower rate limit of said third rate zone; and delivering pacing pulses to the heart if said ventricular contraction rate is less than said lower rate limit of said second rate zone.
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17. A method for classifying cardiac arrhythmias and delivering therapy to the heart comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; computing the time interval between atrial contraction and ventricular contraction (AV); comparing said AV time interval with a predetermined time interval value if said atrial rate is equal to said ventricular rate; classifying the rhythm of the heart as a junctional tachycardia if said ventricular and atrial rates are equal and said AV time interval is less than or equal to said predetermined time interval value; determining whether said AV time interval is regular if said AV time interval is greater than said predetermined time interval value; comparing the ventricular rate with a predetermined crossover rate value if said AV time interval is regular; classifying the rhythm of the heart as a ventricular tachycardia if said ventricular rate is greater than or equal to said predetermined crossover rate value; providing a lower rate limit of a first rate zone and a lower rate limit of a second rate zone, said lower rate limit of said second rat zone being greater than said lower rate limit of said first rate zone; providing a lower rate limit of a third rate zone that is greater than said lower rate limit of said second rate zone; comparing said ventricular contraction rate with said lower rate limit of said third rate zone f said ventricular contraction rate is greater than said ventricular crossover rate to determine if the rhythm of the heart is ventricular fibrillation; comparing said ventricular contraction rate with said lower rate limit of said second rate zone if said ventricular rate is less than said lower rate limit of said third rate zone to determine if the heart is in a fast rhythm or an arrhythmia requiring a cardioverting shock; delivering defibrillation pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said third rate zone; delivering cardioverting pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said second rate zone and less than said lower rate limit of said third rate zone; and delivering pacing pulses to the heart if said ventricular contraction rate is less than said lower rate limit of said second rate zone.
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18. A method for classifying cardiac arrhythmias and delivering therapy to the heart comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; computing the time interval between atrial contraction and ventricular contraction (AV); comparing said AV time interval with a predetermined time interval value if said atrial rate is equal to said ventricular rate; classifying the rhythm of the heart as a junctional tachycardia if said ventricular and atrial rates are equal and said AV time interval is less than or equal to said predetermined time interval value; determining whether said AV time interval is regular if said AV time interval is greater than said predetermined time interval value; comparing the ventricular rate with a predetermined crossover rate value if said AV time interval is regular; classifying the rhythm of the heart as a ventricular tachycardia if said ventricular rate is greater than or equal to said predetermined crossover rate value; providing a lower rate limit of a first rate zone and a lower rate limit of a second rate zone, said lower rate limit of said second rate zone being greater than said lower rate limit of said first rate zone; providing a lower rate limit of a third rate zone being greater than said lower rate limit of said second rate zone; comparing said ventricular contraction rate with said lower rate limit of said third rate zone if said AV time interval is greater than or equal to said SAV time interval; comparing said ventricular contraction rate with said lower rate limit of said second rate zone if said ventricular rate is less than said lower rate limit of said third rate zone; delivering defibrillation pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said third rate zone; delivering cardioverting pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said second rate zone and less than said lower rate limit of said third rate zone; and delivering pacing pulses to the heart if said ventricular contraction rate is less than said lower rate limit of said second rate zone.
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19. A method for classifying cardiac arrhythmias and delivering therapy to the heart comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; computing the time interval between atrial contraction and ventricular contraction (AV); comparing said AV time interval with a predetermined time interval value if said atrial rate is equal to said ventricular rate; classifying the rhythm of the heart as a junctional tachycardia if said ventricular and atrial rates are equal and said AV time interval is less than or equal to said predetermined time interval value; determining whether said atrial rate is regular if the ventricular rate is less than said atrial rate; determining whether said ventricular rate is regular if said atrial rate is determined to be regular; said steps of determining whether the atrial rate is regular and determining whether the ventricular rate is regular for establishing if the heart rhythm is sinus tachycardia or an atrial arrhythmia; further determining whether said AV time interval is regular if said ventricular rate is determined to be regular; classifying the rhythm of the heart as an atrial arrhythmia if said step of further determining determines that said AV time interval is regular to confirm that the rhythm of the heart is an atrial arrhythmia; providing a lower rate limit of a first rate zone and a lower rate limit of a second rate zone, said lower rate limit of said second rate zone being greater than said lower rate limit of said first rate zone; providing a lower rate limit of a third rate zone being greater than said lower rate limit of said second rate zone; comparing said ventricular contraction rate with said lower rate limit of said third rate zone if said AV time interval is determined to be irregular to determine if the rhythm of the heart is ventricular fibrillation; comparing said ventricular contraction rate with said lower rate limit of said second rate zone if said ventricular rate is less than said lower rate limit of said third rate zone to determine if the heart is in a fast rhythm or an arrhythmia requiring a cardioverting shock; delivering defibrillation pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said third rate zone; delivering cardioverting pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said second rate zone and less than said lower rate limit of said third rate zone; and delivering pacing pulses to the heart if said ventricular contraction rate is less than said lower rate limit of said second rate zone.
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20. A method for classifying cardiac arrhythmias and delivering therapy to the heart comprising the steps of:
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sensing the electrical activity of an atrium and a ventricle of the heart; determining the ventricular rate of contraction and the atrial rate of contraction; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; computing the time interval between atrial contraction and ventricular contraction (AV); comparing said AV time interval with a predetermined time interval value if said atrial rate is equal to said ventricular rate; classifying the rhythm of the heart as a junctional tachycardia if said ventricular and atrial rates are equal and said AV time interval is less than or equal to said predetermined time interval value; determining whether said atrial rate is regular if the ventricular rate is less than said atrial rate; determining whether said ventricular rate is regular if said atrial rate is determined to be regular; said steps of determining whether the atrial rate is regular and determining whether the ventricular rate is regular for establishing if the heart rhythm is sinus tachycardia or an atrial arrhythmia; further determining whether said AV time interval is regular if said ventricular rate is determined to be regular; classifying the rhythm of the heart as an atrial arrhythmia if said step of further determining determines that said AV time interval is regular to confirm that the rhythm of the heart is an atrial arrhythmia; further determining whether said AV time interval is regular if either one of said ventricular or atrial rates is determined to be irregular to identify the rhythm of the heart as sinus tachycardia or an atrial arrhythmia; classifying the rhythm of the heart as an atrial arrhythmia with conduction problems if said step of further determining determines that said AV time interval is regular and otherwise classifying the rhythm of the heart as an atrial arrhythmia coincident with ventricular tachycardia or ventricular fibrillation; providing a lower rate limit of a first rate zone and a lower rate limit of a second rate zone, said lower rate limit of said second rate zone being greater than said lower rate limit of said first rate zone; providing a lower rate limit of a third rate zone being greater than said lower rate limit of said second rate zone; comparing said ventricular contraction rate with said lower rate limit of said third rate zone if said step of further determining determines that said AV interval is irregular; comparing said ventricular contraction rate with said lower rate limit of said second rate zone if said ventricular rate is less than said lower rate limit of said third rate zone; delivering defibrillation pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said third rate zone; delivering cardioverting pulses to the heart if said ventricular contraction rate is greater than said lower rate limit of said second rate zone and less than said lower rate limit of said third rate zone; and delivering pacing pulses to the heart if said ventricular contraction rate is less than said lower rate limit of said second rate zone.
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21. A system for classifying cardiac arrhythmias and delivering therapy to the heart comprising:
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sensing means for sensing the ventricular electrical activity and atrial electrical activity of the heart; cardiac arrhythmia classifying means for; determining the ventricular rate of contraction and the atrial rate of contraction based on said sensed ventricular and atrial electrical activity; comparing the ventricular rate with a preset threshold value; comparing the ventricular rate with the atrial rate if the ventricular rate exceeds said preset threshold value; and classifying the rhythm of the heart as ventricular fibrillation or ventricular tachycardia if the ventricular rate is greater than the atrial rate; and means for delivering therapy to the heart in the form of pacing pulses, cardioverting shocks or defibrillating shocks according to the classification of the rhythm of the heart. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification