Apparatus and method for ventricular pacing triggered by detection of early ventricular excitation
First Claim
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1. A cardiac rhythm management device, comprising:
- at least one sensor configured to sense an electrogram waveform representative of the depolarization of the heart;
a processor receiving data from the sensor, wherein the processor is programmed to ensemble-average a digitized electrogram waveform over a predetermined number of QRS complexes and to derive therefrom the time of occurrence of an early electrical event (Q*) from the data by calculation of an absolute derivative of the ensemble-averaged electrogram waveform and normalizing the absolute derivative using a maximum absolute derivative of the ensemble-averaged electrogram waveform and locating a flattest segment of the normalized derivative of the absolute derivative of the ensemble-averaged electrogram within a window of a predetermined length to establish a threshold as a mean plus standard deviation of the flattest segment; and
a pulse generator configured to provide a pacing stimulus to at least one ventricle in timed relation to the Q* event.
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Abstract
A pacing apparatus and method for providing optimum timing for ventricular pacing without referencing atrial activities. The pacing apparatus includes a processor, at least one sensor and a pulse generator. The pacing method includes the sensing of ventricular depolarization and the identification of an early electrical event, such as a depolarization of the HIS bundle or an onset of a ventricular depolarization (Q*). The system derives the proper timing using this early electrical event which provides a predictable relationship with an optimal ventricular pacing signal.
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Citations
13 Claims
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1. A cardiac rhythm management device, comprising:
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at least one sensor configured to sense an electrogram waveform representative of the depolarization of the heart;
a processor receiving data from the sensor, wherein the processor is programmed to ensemble-average a digitized electrogram waveform over a predetermined number of QRS complexes and to derive therefrom the time of occurrence of an early electrical event (Q*) from the data by calculation of an absolute derivative of the ensemble-averaged electrogram waveform and normalizing the absolute derivative using a maximum absolute derivative of the ensemble-averaged electrogram waveform and locating a flattest segment of the normalized derivative of the absolute derivative of the ensemble-averaged electrogram within a window of a predetermined length to establish a threshold as a mean plus standard deviation of the flattest segment; and
a pulse generator configured to provide a pacing stimulus to at least one ventricle in timed relation to the Q* event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for effecting CRT of AF patients, comprising:
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sensing the depolarization of one of the ventricles;
identifying an early electrical event (Q*) in a sensed ventricular depolarization waveform by a template matching algorithm including the steps of;
(i) calculating an ensemble-averaged waveform;
(ii) establishing a Q* point on the ensemble averaged waveform;
(iii) establishing a template; and
(iv) matching a real time electrogram with the template to identify a real time Q* point; and
triggering a pacing stimulus to one or both ventricles in timed relation to the identified event. - View Dependent Claims (12, 13)
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Specification