Pacemaker system with diurnal pattern controlled overdrive for prevention of tachycardia
First Claim
1. A cardiac pacemaker system for pacing a patient, having VP means for generating and delivering ventricular pacing pulses to a patient'"'"'s ventricle, VS means for sensing ventricular QRS and T waves, rate means for determining the patient'"'"'s spontaneous heart rate, and control means for controlling when said VP means generates and delivers ventricular pacing pulses and the pacing rate of such pulses, wherein said control means further comprises VT prevention means for controlling said VP means to deliver pacing pulses at a rate overriding the patient'"'"'s spontaneous rate when a threshold of refractory dispersion is detected during patient awakening, said VT prevention means comprising:
- awakening means for determining an awakening period when the patient is awakening;
depolarization means for determining a first measure of dispersion of the patient'"'"'s depolarization wave during awakening;
repolarization means for determining a second measure of dispersion of the patient'"'"'s repolarization wave during awakening; and
intervention means for controlling said VP means to generate and deliver pacing pulses at an intervention rate that overrides the patient'"'"'s spontaneous rate as a function of said first and second measures.
1 Assignment
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Accused Products
Abstract
There is provided a cardiac pacemaker system with a ventricular tachycardia prevention feature, whereby the pacemaker monitors ventricular activity during each patient awakening period to determine when VT is likely. In a preferred embodiment, QRS and T wave templates are generated cyclically during awakening, and compared to normal templates to obtain a measure of variability, indicative of refractory dispersion and thus of probable VT. Ventricular extra-systoles are also monitored and analyzed during the awakening period to see how closely they occur to the ventricular vulnerable period. When the monitored data indicates VT probability during awakening, the pacemaker responds by overdriving the heart with an intervention pacing rate which is continually adjusted as a function of the currently obtained data.
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Citations
20 Claims
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1. A cardiac pacemaker system for pacing a patient, having VP means for generating and delivering ventricular pacing pulses to a patient'"'"'s ventricle, VS means for sensing ventricular QRS and T waves, rate means for determining the patient'"'"'s spontaneous heart rate, and control means for controlling when said VP means generates and delivers ventricular pacing pulses and the pacing rate of such pulses, wherein said control means further comprises VT prevention means for controlling said VP means to deliver pacing pulses at a rate overriding the patient'"'"'s spontaneous rate when a threshold of refractory dispersion is detected during patient awakening, said VT prevention means comprising:
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awakening means for determining an awakening period when the patient is awakening; depolarization means for determining a first measure of dispersion of the patient'"'"'s depolarization wave during awakening; repolarization means for determining a second measure of dispersion of the patient'"'"'s repolarization wave during awakening; and intervention means for controlling said VP means to generate and deliver pacing pulses at an intervention rate that overrides the patient'"'"'s spontaneous rate as a function of said first and second measures. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A cardiac pacemaker system for pacing a patient, having VP means for generating and delivering ventricular pacing pulses to a patient'"'"'s ventricle, VS means for sensing ventricular QRS and T waves, rate means for determining the patient'"'"'s spontaneous heart rate, and control means for controlling when said VP means generates and delivers ventricular pacing pulses and the pacing rate of such pulses, wherein said control means further comprises VT prevention means for controlling said VP means to deliver pacing pulses at a rate overriding the patient'"'"'s spontaneous rate when a threshold of refractory dispersion is detected during patient awakening, said VT prevention means comprising:
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awakening means for determining an awakening period when the patient is awakening; dispersion data means for determining during said awakening period data representative of ventricular refractory dispersion; threshold means for determining from said data when patient refractory dispersion exceeds said threshold; and overdrive control means for setting pacing rate at an intervention rate which is adjusted as a function of said data. - View Dependent Claims (9)
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10. A pacemaker system for pacing a patient'"'"'s heart, having VP means for generating and delivering pacing pulses to a patient'"'"'s ventricle, rate control means for controlling the rate of said pacing pulses, and said rate control means having VT prevention means for controlling said rate to an intervention rate when said patient has a detected measure of refractory dispersion during awakening, said VT prevention means comprising:
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awakening means for determining when said patient is in a state of awakening; dispersion means for determining a measure of dispersion of ventricular refractoriness; and intervention means for setting and continually adjusting said intervention rate as a function of said dispersion measure. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification