System and method for deriving hemodynamic signals from a cardiac wall motion sensor
First Claim
1. A processing system for an implantable cardiac device, the implantable cardiac device having a cardiac wall acceleration sensor associated therewith for providing a cardiac wall acceleration signal as a function of cardiac wall contractile motion, the cardiac wall acceleration sensor adapted to he positioned at an apex of a patient'"'"'s ventricle so as to maximize the detection of cardiac wall contractile motion acceleration, the processing system comprising:
- input circuitry for receiving the cardiac wall acceleration signal; and
processing circuitry, coupled to the input circuitry, for processing the cardiac wall acceleration signal to detect the cardiac wall contractile motion, and for deriving a hemodynamic signal representative of cardiac hemodynamic performance based upon the cardiac wall acceleration signal.
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Abstract
A processing system and method are provided for deriving an improved hemodynamic indicator from cardiac wall acceleration signals. The cardiac wall acceleration signals are provided by a cardiac wall motion sensor that responds to cardiac mechanical activity. The cardiac wall acceleration signals are integrated over time to derive cardiac wall velocity signals, which are further integrated over time to derive cardiac wall displacement signals. The cardiac wall displacement signals correlate to known hemodynamic indicators, and are shown to be strongly suggestive of hemodynamic performance. An implantable cardiac stimulating device which uses cardiac wall displacement signals to detect and discriminate cardiac arrhythmias is also provided.
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Citations
34 Claims
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1. A processing system for an implantable cardiac device, the implantable cardiac device having a cardiac wall acceleration sensor associated therewith for providing a cardiac wall acceleration signal as a function of cardiac wall contractile motion, the cardiac wall acceleration sensor adapted to he positioned at an apex of a patient'"'"'s ventricle so as to maximize the detection of cardiac wall contractile motion acceleration, the processing system comprising:
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input circuitry for receiving the cardiac wall acceleration signal; and processing circuitry, coupled to the input circuitry, for processing the cardiac wall acceleration signal to detect the cardiac wall contractile motion, and for deriving a hemodynamic signal representative of cardiac hemodynamic performance based upon the cardiac wall acceleration signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for detecting cardiac wall displacements utilizing an implantable cardiac stimulation device, comprising:
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acceleration sensing means, adapted to be positioned at an apex of a patient'"'"'s ventricle, so as to be most sensitive to detecting the cardiac wall displacements and for providing a physiological signal corresponding to cardiac wall displacements; processing means, coupled to the acceleration sensing means, for processing the acceleration signal and for detecting the magnitude of the cardiac wall displacements; means for sensing electrical cardiac depolarization signals; means for detecting a change in the hemodynamic signal indicative of a change in the magnitude of the cardiac wall displacement; and means for classifying an electrical cardiac depolarization signal as an ectopic beat whenever a corresponding decrease in the hemodynamic signal is detected.
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13. A processing system for an implantable cardiac device, the implantable cardiac device having a cardiac wall motion sensor associated therewith for detecting cardiac wall motion and for providing a first hemodynamic signal related thereto, the cardiac wall motion sensor adapted to be positioned at an apex of a patient'"'"'s ventricle so as to maximize the detection of the acceleration of the cardiac wall motion, the processing system comprising:
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input circuitry for receiving and selectively filtering the first hemodynamic signal and to attenuate unwanted body motion signals; and processing circuitry, coupled to the input circuitry, for deriving a second hemodynamic signal based on the filtered first hemodynamic signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A processing system for detecting cardiac wall displacement in an implantable cardiac stimulation device, the system comprising:
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pulse generating means for providing stimulation therapy to a patient'"'"'s heart; an endocardial lead having an axis along a length of the lead, the lead further having a stimulation electrode, the electrode adapted to be positioned at the apex of a patient'"'"'s ventricle, the lead having acceleration sensing means located proximal to the stimulation electrode, for providing an acceleration signal as a function of cardiac wall contractile motion, the acceleration sensing means being most sensitive to cardiac wall contractile motion when the stimulation is positioned at the ventricular apex; and processing means, coupled to the acceleration sensing means, for integrating the acceleration signal twice so as to derive a cardiac wall displacement signal, and for controlling the pulse generating means to alter the stimulation therapy based on the cardiac wall displacement signal. - View Dependent Claims (27, 28)
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29. A processing system for detecting ventricular wall contractions, the system comprising:
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acceleration sensing means, adapted to be positioned at an apex of a patient'"'"'s ventricle, for providing an acceleration signal as a function of ventricular wall contractions, the acceleration sensing means when so positioned being most sensitive to the acceleration of ventricular wall contractions; processing means, coupled to the acceleration sensing means, for processing the acceleration signal to detect an amplitude of the ventricular wall contractions; means for sensing electrical cardiac depolarization signals; means for determining hemodynamic stability based on the amplitude of the ventricular wall contractions; means for classifying an electrical cardiac depolarization signal as pathological whenever an unstable hemodynamic signal is detected and physiological whenever a stable hemodynamic signal is detected.
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30. A processing system for detecting hemodynamic performance in an implantable cardiac stimulation device, comprising:
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a cardiac wall motion sensor associated therewith for providing an acceleration signal, the cardiac wall motion sensor adapted to be positioned at an apex of a patient'"'"'s ventricle to thereby be most sensitive to detecting acceleration of cardiac wall contractile motion the acceleration signal being a function of the acceleration of the cardiac wall contractile motion; means for selectively filtering the acceleration signal to derive a magnitude of the acceleration of cardiac wall contractile motion; detection means for detecting an indication of bradycardia as a function of at least the acceleration signal; and pulse generating means, coupled to the detection means, for generating stimulation pulses when an indication of bradycardia is detected. - View Dependent Claims (31, 32, 33)
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34. A processing system for an implantable cardiac device, the implantable cardiac device having a cardiac wall acceleration sensor adapted for maximizing the measurement of the acceleration of cardiac wall contractile motion, the processing system comprising:
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input circuitry for receiving the cardiac wall acceleration signal; and processing circuitry, coupled to the input circuitry, for processing the cardiac wall acceleration signal to detect the cardiac wall contractile motion, and for deriving a hemodynamic signal representative of cardiac hemodynamic performance based on the cardiac wall acceleration signal.
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Specification