Method for providing dynamic gain over electrocardiographic data with the aid of a digital computer
First Claim
1. A method for providing dynamic gain over electrocardiographic data with the aid of a digital computer, comprising the steps of:
- continuously sensing and recording cutaneous action potentials with an ambulatory monitor recorder and representing each of the action potentials as a compression code in a sequence stored into the monitor recorder'"'"'s memory;
electronically interfacing the monitor recorder with an external download station and offloading the sequence of compression codes from the memory;
decompressing the sequence of compression codes on the download station into a time series that comprises a digital representation of a raw electrocardiography signal;
identifying cardiac waveforms within the time series on the download station and measuring peak-to-peak voltages in the cardiac waveforms that fall within a preferred voltage range inside of a temporal window in the time series;
statistically representing a correlation between the peak-to-peak voltages on the download station and determining a signal gain that places the correlation between the peak-to-peak voltages within the preferred range; and
gaining the cardiac waveforms on the download station by the signal gain.
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Abstract
In one embodiment, ECG data collected during the long-term monitoring are compressed through a two-step compression algorithm executed by an electrocardiography monitor. Minimum amplitude signals may become indistinguishable from noise if overly inclusive encoding is employed in which voltage ranges are set too wide. The resulting ECG signal will appear “choppy” and uneven with an abrupt slope. The encoding used in the first stage of compression can be dynamically rescaled on-the-fly when the granularity of the encoding is too coarse. In a further embodiment, offloaded ECG signals are automatically gained as appropriate on a recording-by-recording basis to preserve the amplitude relationship between the signals. Raw decompressed ECG signals are filtered for noise content and any gaps in the signals are bridged. The signal is then gained based on a statistical evaluation of peak-to-peak voltage (or other indicator) to land as many ECG waveforms within a desired range of display.
267 Citations
20 Claims
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1. A method for providing dynamic gain over electrocardiographic data with the aid of a digital computer, comprising the steps of:
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continuously sensing and recording cutaneous action potentials with an ambulatory monitor recorder and representing each of the action potentials as a compression code in a sequence stored into the monitor recorder'"'"'s memory; electronically interfacing the monitor recorder with an external download station and offloading the sequence of compression codes from the memory; decompressing the sequence of compression codes on the download station into a time series that comprises a digital representation of a raw electrocardiography signal; identifying cardiac waveforms within the time series on the download station and measuring peak-to-peak voltages in the cardiac waveforms that fall within a preferred voltage range inside of a temporal window in the time series; statistically representing a correlation between the peak-to-peak voltages on the download station and determining a signal gain that places the correlation between the peak-to-peak voltages within the preferred range; and gaining the cardiac waveforms on the download station by the signal gain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for optimizing cardiac signal detail capture during ambulatory monitoring using a monitor recorder, comprising the steps of:
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defining a temporal window and a peak-to-peak voltage threshold; sensing a series of electrocardiography values with a monitor recorder; defining a plurality of bins, each of the bins comprising an upper electrocardiography threshold, a lower electrocardiography threshold, and a code; processing the series of the electrocardiography values in successively-occurring temporal windows, for each temporal window comprising the steps of; calculating a peak-to-peak voltage of the electrocardiography values in the temporal window; adjusting the upper electrocardiography threshold and the lower electrocardiography threshold of each of the plurality of bins when the peak-to-peak voltage is less than the peak-to-peak voltage threshold; and encoding each of the electrocardiography values from the series with the code for the bin comprised with an upper electrocardiography threshold and a lower electrocardiography threshold between which the electrocardiography value falls; and writing each of the codes into a sequence in a non-volatile memory of the monitor recorder. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification