VENTRICULAR CAPTURE TESTING BY ANALYSIS OF AN ENDOCARDIAL ACCELERATION SIGNAL IN AN ACTIVE IMPLANTABLE MEDICAL DEVICE
First Claim
1. An active implantable medical device for cardiac pacing, resynchronization and/or defibrillation, comprising:
- ventricular pacing means for delivering stimulation pulses of low energy to be applied to an electrode implanted in the right and/or left ventricular cavity of a patient andmeans for testing ventricular capture, for detecting the onset of ventricular contraction resulting from delivery of a stimulation pulse, comprising;
an acceleration sensor having as an output an EA signal representative of a patient'"'"'s endocardiac acceleration; and
means for analyzing the EA signal for determining a presence and an absence of a ventricular capture,Wherein;
the means for analyzing the EA signal comprises means for;
isolating in the EA signal at least one EA component of endocardial acceleration corresponding to a first major noise of the heart, and at least one EA component describing the continuous variation of said EA signal in a bounded temporal window corresponding to a fraction of a cardiac cycle;
extracting from said at least one EA component n indicators (PEA_i, LEA_i), with n≧
2, representative of the EA signal, andforming a vector EA (X_i) of dimension n from the n indicators thus extracted;
the device further comprising a classifier means for, during a preliminary phase;
acquiring a plurality of EA signals at a stimulation energy level high enough to cause a capture and forming a corresponding plurality of first reference EA vectors (X_capt_ref_p);
acquiring a plurality of EA signals in a spontaneous rhythm of the patient in the absence of ventricular pacing and forming a corresponding plurality of second reference EA vectors (X_spont_ref_p) andfrom the first and second vectors thus acquired, partitioning the n-dimensional space of the EA vectors into two subspaces corresponding respectively to the presence and absence of a capture; and
wherein the means for testing ventricular capture further comprises means for;
acquiring at least one EA signal at a current level of stimulation energy, and forming at least one corresponding current EA vector (X_i), anddiscriminating the presence or absence of ventricular capture based on the position of the current EA vector in one of said two sub-spaces of said n-dimensional space of EA vectors.
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Abstract
An active implantable medical device such as a cardiac prosthesis, including ventricular capture testing by analysis of an endocardial acceleration signal. The device isolates in an endocardial acceleration (“EA”) signal an EA component, extracts from it, n representative indicators (PEA_i, LEA_i), and forms a vector EA (X_i) from these indicators. A classifier allows acquiring reference EA signals at a stimulation energy level sufficient to cause a capture, and in spontaneous rhythm in the absence of ventricular pacing and forms a corresponding plurality of first reference EA vectors. The n-dimensional space of the EA vectors is partitioned into two corresponding subspaces. The presence or absence of a capture is discriminated based on the position of the current EA vector (X_i) in one or other of these two sub-spaces. The representative indicators may be: the value of peak to peak amplitude, the width, the moment of occurrence of the peak, the starting time and the ending time of the EA1 and/or EA2 components, the signal to noise ratio (SNR), the contrast value, the entropy value, and the cumulative energy of the EA1 and/or EA2 component, or the value of the peak-to-peak amplitude of the EA 4 component.
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Citations
17 Claims
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1. An active implantable medical device for cardiac pacing, resynchronization and/or defibrillation, comprising:
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ventricular pacing means for delivering stimulation pulses of low energy to be applied to an electrode implanted in the right and/or left ventricular cavity of a patient and means for testing ventricular capture, for detecting the onset of ventricular contraction resulting from delivery of a stimulation pulse, comprising; an acceleration sensor having as an output an EA signal representative of a patient'"'"'s endocardiac acceleration; and means for analyzing the EA signal for determining a presence and an absence of a ventricular capture, Wherein; the means for analyzing the EA signal comprises means for; isolating in the EA signal at least one EA component of endocardial acceleration corresponding to a first major noise of the heart, and at least one EA component describing the continuous variation of said EA signal in a bounded temporal window corresponding to a fraction of a cardiac cycle; extracting from said at least one EA component n indicators (PEA_i, LEA_i), with n≧
2, representative of the EA signal, andforming a vector EA (X_i) of dimension n from the n indicators thus extracted; the device further comprising a classifier means for, during a preliminary phase; acquiring a plurality of EA signals at a stimulation energy level high enough to cause a capture and forming a corresponding plurality of first reference EA vectors (X_capt_ref_p); acquiring a plurality of EA signals in a spontaneous rhythm of the patient in the absence of ventricular pacing and forming a corresponding plurality of second reference EA vectors (X_spont_ref_p) and from the first and second vectors thus acquired, partitioning the n-dimensional space of the EA vectors into two subspaces corresponding respectively to the presence and absence of a capture; and wherein the means for testing ventricular capture further comprises means for; acquiring at least one EA signal at a current level of stimulation energy, and forming at least one corresponding current EA vector (X_i), and discriminating the presence or absence of ventricular capture based on the position of the current EA vector in one of said two sub-spaces of said n-dimensional space of EA vectors. - View Dependent Claims (2, 3, 4, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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5. The device of claim 5, wherein the n representative indicators of the EA signal further comprise morphology indicators chosen from among the group consisting of:
- the SNR, the contrast value, the value of entropy, and the cumulative energy, of the EA component.
- View Dependent Claims (6, 7)
Specification