Method of quantifying cardiac fibrillation using wavelet transform
First Claim
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1. A method of quantifying cardiac fibrillation comprising the steps of:
- (a) sensing the electrical signals of a patient'"'"'s heart to provide an ECG signal;
(b) detecting the presence of a fibrillation event;
(c) performing a wavelet transform on the fibrillation event in said ECG signal; and
(d) analyzing the resultant wavelet transform by searching for an absence of signal spikes to characterize the fibrillation event.
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Abstract
The present invention provides a system and method for characterizing cardiac fibrillation using wavelet transforms. By characterizing the seriousness of a fibrillation episode, a defibrillation shock may be delivered to the heart with less excess energy than conventional ICDs. A wavelet transform is performed on a digitized ECG using a second derivative weight function and the results are analyzed for missing "peaks" in the data. The more serious the fibrillation, the more peaks will be missing from the data. This information may then used to modify the voltage of the defibrillation shocks as a function of the seriousness of the fibrillation.
231 Citations
10 Claims
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1. A method of quantifying cardiac fibrillation comprising the steps of:
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(a) sensing the electrical signals of a patient'"'"'s heart to provide an ECG signal; (b) detecting the presence of a fibrillation event; (c) performing a wavelet transform on the fibrillation event in said ECG signal; and (d) analyzing the resultant wavelet transform by searching for an absence of signal spikes to characterize the fibrillation event. - View Dependent Claims (2, 3, 4, 5)
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6. A device for characterizing fibrillation of a patient'"'"'s heart comprising:
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means for sensing an ECG signal from said patient'"'"'s heart; means for performing a wavelet transform on said ECG signal; and means for analyzing a resultant transform for an absence of characteristic spikes. - View Dependent Claims (7)
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8. A method for characterizing fibrillation in an ECG signal to determine a level of seriousness of an arrhythmia comprising the steps of:
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(a) sensing an ECG signal from a patient'"'"'s heart; (b) performing a wavelet transform characterized by a second derivative function for a predetermined frequency range on a series of QRS complexes from the ECG of the patient during fibrillation to provide a resultant transform; (c) determining a number of missing peaks in the resultant transform; and (d) characterizing the seriousness of the fibrillation based on the number of missing peaks. - View Dependent Claims (9)
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10. An implantable defibrillator system comprising:
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electrode means adapted to be coupled to a patient'"'"'s heart for use in sensing electrical signals from said patient'"'"'s heart; sensing means having an input connected to said electrode means for sensing analog ECG heart signals; analog-to-digital means for converting the analog ECG heart signal into a digitized ECG heart signal; and fibrillation characterizing means for characterizing a level of severity of a fibrillation signal including means for performing a wavelet transform on said digitized ECG signal to provide a resultant transform and for analyzing the resultant transform for an absence of characteristic peaks.
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Specification