Implantable cardiac stimulation device, system and method which provides an electrogram signal facilitating measurement of slow-changing electrogram features
First Claim
1. An implantable cardiac system including an implantable cardiac stimulation device, the system providing a heart activity signal of a heart facilitating measurement of slowly changing electrogram features, the system comprising:
- at least one implantable electrode arrangement that senses cardiac electrical activity and provides an intracardiac electrogram signal;
a first high-pass filter with a cutoff frequency at an upper frequency breakpoint that filters the intracardiac electrogram signal, andan equalizer that filters the filtered intracardiac electrogram signal, the equalizer having a transfer function derived by multiplying a reciprocal of the transfer function of the first high pass filter by a transfer function of a second high pass filter with a cutoff frequency at a lower frequency breakpoint, wherein the transfer function of the equalizer is non-decreasing for frequencies up to the lower frequency breakpoint.
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Abstract
An implantable cardiac system including an implantable cardiac stimulation device provides a heart activity signal of a heart facilitating measurement of slowly changing electrogram features. The system comprises at least one implantable electrode arrangement that senses cardiac electrical activity and provides an intracardiac electrogram signal, a first high pass filter that filters the electrogram and an equalizer that filters the filtered electrogram signal. The equalizer has a transfer function that is non-decreasing for frequencies up to a lower frequency breakpoint that is less than the upper frequency breakpoint, decreasing for frequencies between the lower frequency breakpoint and the upper frequency breakpoint, and generally flat for frequencies above the upper frequency breakpoint through a bandpass region of interest.
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Citations
16 Claims
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1. An implantable cardiac system including an implantable cardiac stimulation device, the system providing a heart activity signal of a heart facilitating measurement of slowly changing electrogram features, the system comprising:
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at least one implantable electrode arrangement that senses cardiac electrical activity and provides an intracardiac electrogram signal; a first high-pass filter with a cutoff frequency at an upper frequency breakpoint that filters the intracardiac electrogram signal, and an equalizer that filters the filtered intracardiac electrogram signal, the equalizer having a transfer function derived by multiplying a reciprocal of the transfer function of the first high pass filter by a transfer function of a second high pass filter with a cutoff frequency at a lower frequency breakpoint, wherein the transfer function of the equalizer is non-decreasing for frequencies up to the lower frequency breakpoint. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In an implantable cardiac system, a method of providing a heart activity signal of a heart which facilitates measurement of slowly changing electrogram features, the method comprising:
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sensing cardiac electrical activity with at least one implanted electrode arrangement to provide an electrogram signal; filtering the electrogram signal with a first high-pass filter with a cutoff frequency at an upper frequency breakpoint; and filtering the filtered electrogram signal with a equalizer having a transfer function that is;
non-decreasing for frequencies up to a lower frequency breakpoint that is less than the upper frequency breakpoint, decreasing for frequencies between the lower frequency breakpoint and the upper frequency breakpoint, and generally flat for frequencies above the upper frequency breakpoint through a bandpass region of interest. - View Dependent Claims (11, 12, 13)
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14. An implantable cardiac system including an implantable cardiac stimulation device, the system providing a heart activity signal of a heart facilitating measurement of slowly changing electrogram features, the system comprising:
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at least one implantable electrode arrangement that senses cardiac electrical activity and provides an electrogram signal; a first high-pass filter with a cutoff frequency at an upper frequency breakpoint that filters the electrogram signal, and a plurality of serially arranged equalizers that filter the filtered electrogram signal, each equalizer having a transfer function derived as a function of a reciprocal of the transfer function of the first high pass filter and a transfer function of a second high pass filter with a cutoff frequency at a lower frequency breakpoint. - View Dependent Claims (15, 16)
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Specification