Systems and methods for denoising physiological signals during electrical neuromodulation
Systems and methods are described for denoising, or filtering out, unwanted noise or interference, from biological or physiological parameter signals or waveforms such as ECG signals caused by application of electromagnetic energy (e.g., electrical stimulation) in a vicinity of sensors configured to obtain the biological or physiological parameter signals.
1. A system comprising:
an electrical stimulation system; and
a denoising system comprising circuitry configured to:
receive original ECG signals from an ECG electrode array;
receive a synchronization signal from the electrical stimulation system indicative of initiation of electrical stimulation being applied by the electrical stimulation system;
denoise the original ECG signals after receipt of the synchronization signal via one or more denoising stages, wherein denoising the original ECG signals comprises blanking portions of the original ECG signals and modifying the blanked portions to provide modified ECG signals with reduced transitory noise;
determine that electrical stimulation has been stopped based on the synchronization signal; and
cause the original ECG signals to bypass the one or more denoising stages upon determining that electrical stimulation has stopped.
2. The system of claim 1 , wherein the circuitry comprises one or more processors further configured to digitize the portions of the original ECG signals.
3. The system of claim 2 , wherein the one or more processors are further configured to refine the modified ECG signals using at least one of a linear phase filter or a digital finite impulse response filter to create denoised ECG signals.
4. The system of claim 3 , wherein the one or more processors are further configured to:
convert the denoised ECG signals into an analog signal to facilitate output on a display; and
output the denoised ECG signals for presentation on the display.
5. The system of claim 4 , further comprising
a patient monitor comprising a display configured to display the output.
6. The system of claim 1 , wherein said blanking comprises temporarily removing values stored at memory locations corresponding to the portions of the original ECG signals and wherein said modifying the blanked portions comprises interpolation, and wherein said interpolation comprises identifying a last value prior to said blanking and a first value after said blanking and replacing the removed values in the memory locations with interpolated values between the last value and the first value in the memory locations.
7. The system of claim 6 , wherein the circuitry comprises one or more processors further configured to filter out 50 Hz or 60 Hz line frequency components for a time period prior to said blanking and following said blanking to ensure the first value and the last value are not affected by the 50 Hz or 60 Hz line frequency components.
8. The system of claim 1 , wherein said blanking comprises temporarily removing values stored at memory locations corresponding to the portions of the original ECG signals and wherein said modifying the blanked portions comprises interpolation, and wherein said interpolation comprises calculating modified values to replace the removed values in the memory locations.
9. The system of claim 1 , wherein said blanking comprises temporarily removing values stored at memory locations corresponding to the portions of the original ECG signals and wherein said modifying the blanked portions comprises replacing the removed values with a last known good value prior to said blanking.
10. The system of claim 1 , wherein the circuitry comprises sample and hold circuitry.
11. The system of claim 1 , wherein the electrical stimulation system is a cardio pulmonary nerve stimulation system.
12. The system of claim 1 , further comprising one or more switches configured to open and close based on the synchronization signal.
13. The system of claim 1 , wherein the synchronization signal is continuously delivered for a duration of the electrical stimulation.
14. A system comprising:
an electrical stimulation system; and
a denoising system comprising one or more processors configured to, upon execution of stored instructions on a non-transitory computer-readable medium:
receive one or more original ECG signals from an ECG electrode array;
receive a synchronization signal from the electrical stimulation system indicative of initiation of electrical stimulation being applied by the electrical stimulation system;
denoise the one or more original ECG signals after receipt of the synchronization signal via a denoising sub-process, wherein denoising the one or more original ECG signals comprises blanking portions of the one or more original ECG signals and modifying the blanked portions to provide one or more modified ECG signals with reduced transitory noise;
output the one or more modified ECG signals for display;
determine that electrical stimulation has been stopped based on the synchronization signal; and
cause the one or more original ECG signals to bypass the denoising sub-process upon determining that electrical stimulation has stopped.
15. The system of claim 14 , further comprising an alert generation subsystem configured to generate an alert if a characteristic of the one or more original ECG signals is out of a threshold range.
16. The system of claim 15 , wherein the characteristic is an R-R interval between successive R waves of the one or more original ECG signals.
17. The system of claim 14 , wherein the electrical stimulation system is a cardio pulmonary nerve stimulation system.
18. The system of claim 14 , further comprising one or more switches configured to open and close based on the synchronization signal.
19. The system of claim 14 , wherein the synchronization signal is continuously delivered for a duration of the electrical stimulation.
20. The system of claim 19 , wherein the synchronization signal is in an “on” state when electrical stimulation is being applied and in an “off” state when electrical stimulation has stopped.