Method and apparatus for observation of ventricular late potentials
First Claim
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1. A method of detecting late potentials at the surface of a patient comprising the step of:
- (a) acquiring two or more ECG signals at a plurality of external locations on the surface of a patient;
(b) filtering the surface ECG signals with a bandpass filter;
(c) digitizing the acquired ECG signals by continuous sampling at a rate equal to or greater than the Nyquist rate;
(d) storing the digitized ECG signals;
(e) processing the digitized ECG signals to reduce low frequency signal components;
(f) selecting a reference signal with the remaining ECG signals referred to as input signals and selecting a filter window in an ECG cycle from one or more of the digitized ECG input signals and defining filter intervals within said filter window;
(g) calculating a feedback coefficient ui associated with an adaptive filter algorithm for each filter interval within a filter window in an ECG cycle from one or more of the digitized ECG input signals;
(h) initializing a bias weight associated with an adaptive filtering algorithm for each filter interval by computing an initial value for the bias weight associated with the filter interval;
(i) thereafter adaptively filtering in time-sequenced manner selected filter intervals of the input signals; and
(j) displaying or storing the results of the adaptive filtering step.
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Abstract
The present invention is directed to a method and apparatus for enhancing high resolution ECG signals acquired with electrodes on the surface of a patient'"'"'s thorax so that ventricular late potentials can be detected and observed. The ECG signals are detected, measured and digitized and are then processed to remove low frequency components and preferably, common mode signals. Enhancement is then accomplished by filtering out the remaining electrical interference caused by underlying muscle tissue, nerve tissue and environmental noise with a particular adaptive filtering technique.
100 Citations
42 Claims
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1. A method of detecting late potentials at the surface of a patient comprising the step of:
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(a) acquiring two or more ECG signals at a plurality of external locations on the surface of a patient; (b) filtering the surface ECG signals with a bandpass filter; (c) digitizing the acquired ECG signals by continuous sampling at a rate equal to or greater than the Nyquist rate; (d) storing the digitized ECG signals; (e) processing the digitized ECG signals to reduce low frequency signal components; (f) selecting a reference signal with the remaining ECG signals referred to as input signals and selecting a filter window in an ECG cycle from one or more of the digitized ECG input signals and defining filter intervals within said filter window; (g) calculating a feedback coefficient ui associated with an adaptive filter algorithm for each filter interval within a filter window in an ECG cycle from one or more of the digitized ECG input signals; (h) initializing a bias weight associated with an adaptive filtering algorithm for each filter interval by computing an initial value for the bias weight associated with the filter interval; (i) thereafter adaptively filtering in time-sequenced manner selected filter intervals of the input signals; and (j) displaying or storing the results of the adaptive filtering step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for detecting late potentials at the surface of a patient comprising:
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(a) a means for acquiring two or more ECG signals at a plurality of external locations on the surface of a patient; (b) means for digitizing the acquired ECG signals by continuous sampling at a rate equal to or grater than the Nyquist rate; (d) a means for storing the digitized ECG signals; (e) a means for processing the digitized ECG signals to reduce low frequency signal components; (f) means for selecting a reference signal with the remaining ECG signals referred to as input signals and a means for selecting a filter window in an ECG cycle from one or more of the digitized ECG input signals and defining filter intervals within said filter window; (g) a means for calculating a feedback coefficient ui associated with an adaptive filter algorithm for each filter interval within a filter window in an ECG cycle from one or more of the digitized ECG input signals; (h) a means for initializing a bias weight associated with an adaptive filtering algorithm for each filter interval by computing a initial value for the bias weight associated with the filter interval; (i) a means for thereafter adaptively filtering in time-sequenced manner selected filter intervals of the input signals; and (j) a means for displaying or storing the results of the adaptive filtering step. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method of detecting low level biophysical signals of a cyclic nature at the surface of a patient comprising the steps of:
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(a) acquiring two or more biophysical signals at a plurality of external locations on the surface of a patient; (b) filtering the surface biophysical signals with a bandpass filter; (c) digitizing the acquired biophysical signals by continuous sampling at a rate equal to or greater than the Nyquist rate; (d) storing the digitized biophysical signals; (e) processing the digitized biophysical signals to reduce low frequency signal components; (f) selecting a reference signal with the remaining biophysical signals referred to as input signals and selecting a filter window in a biophysical cycle from one or more of the digitized biophysical input signals and defining filter intervals within said filter window; (g) calculating a feedback coefficient ui associated with an adaptive filter algorithm for each filter interval within a filter window in a cycle of the biophysical signal from one or more of the digitized biophysical input signals; (h) initializing a bias weight associated with an adaptive filtering algorithm for each filter interval by computing an initial value for the bias weight associated with the filter interval; (i) thereafter adaptively filtering in time-sequenced manner selected filter intervals of the input signals; and (j) displaying or storing the results of the adaptive filtering step.
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42. An apparatus for detecting low level biophysical signals of a cyclic nature at the surface of a patient comprising:
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(a) means for acquiring two or more biophysical signals at a plurality of external locations on the surface of a patient; (b) means for bandpass filtering the surface biophysical signals; (c) a means for digitizing the acquired biophysical signals by continuous sampling at a rate equal to or greater than the Nyquist rate; (d) a means for storing the digitized biophysical signals; (e) a means for processing the digitized biophysical signals to reduce low frequency signal components; (f) a means for selecting a reference signal with the remaining biophysical signals referred to as input signals and a means for selecting a filter window in a biophysical cycle from one or more of the digitized biophysical input signals and defining filter intervals within said filter window; (g) a means for calculating a feedback coefficient ui associated with an adaptive filter algorithm for each filter interval within a filter window in a cycle of the biophysical signal from one or more of the digitized biophysical input signals; (h) a means for initializing a bias weight associated with an adaptive filtering algorithm for each filter interval by computing an initial value for the bias weight associated with the filter interval; (i) a means for thereafter adaptively filtering in time-sequenced manner selected filter intervals of the input signals; and (j) a means for displaying or storing the results of the adaptive filtering step.
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Specification