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Preprocess of HRV Analysis

Preprocess of HRV Analysis

Hello there,

I have a question on HRV Analyzer.vi, one of the samples of LabVIEW Biomedical Toolkit 2013. In this VI near-DC component of R-R interval signal is removed with WA Detrend.vi. The following article describes why detrending is important for HRV analysis (see Preprocessing section), but the reason that it uses Daubechies 6 wavelet and the threshold frequency should be 0.01 is not found so far.

Using LabVIEW for Heart Rate Variability Analysis - National Instruments

http://www.ni.com/example/30832/en/

Another article indicates that wavelet analysis-based detrend with Daubechies 6 wavelet is effective for preprocessing ECG signal.

LabVIEW for ECG Signal Processing - National Instruments

http://www.ni.com/white-paper/6349/en/

Is it a well-known fact that this wavelet is also suitable for the HRV signal? In addition, I hope to know how the threshold frequency is set 0.01. Is it decided with the following equation?

http://www.ni.com/cms/images/devzone/tut/trend%20level.JPG

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Re: Preprocess of HRV Analysis

Hi,

For HRV analysis itself, it doen's have to include detrend stage. It is based on what you want to get. If you only want to extract the power of LF and HF, then you don't need to remove the baseline. If you would like to calcuate the power in VLF, then the baseline may influence the result (for analyzing 24 hours HRV, VLF refers to 0.003-0.04Hz).

And there are different methods -  not just wavelet. We just give an example, and use the same parameter as in ECG analysis. You could try others.

For a standardized HRV analysis, please refer to reference [1] in http://www.ni.com/example/30832/en/.

Thanks!

ZJ

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Re: Preprocess of HRV Analysis

And for how to use wavelet detrend VI, please refer the VI's help in Advanced Signal Processing Toolkit.

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Re: Preprocess of HRV Analysis

Hi ZJ,

Thank you for the information. I guess you created this sample, right? If so, is it correct to say there is not any particular reason you chose Daubechies 6 and 0.01 Hz as the threshold? I was thinking the VI is designed to eliminate vibration that derives from body movement or breathing under a certain circumstance with WA Detrend.vi, and the parameters fed to it was selected for this purpose.

Naoki

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Re: Preprocess of HRV Analysis

The reason we add here is just to show the functionality about how to remove the baseline wandering in biosignal. Not specific for HRV analysis. This is an example, you could modify it to your requirements.

Thanks!

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Re: Preprocess of HRV Analysis

Hi ZJ,

Thanks for the update. I understand the parameters are not designed for any specific target.

Naoki

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Re: Preprocess of HRV Analysis

Hello there... I am new to Labview Biomedical Toolkit... i was trying to extract data from ecg data downloaded from Physiobank... I was wishing to extract the data from the ecg to input the data into ANN...but I cannot use the ECG extractor...the extractor gives random errors like The filter type and everything...please help

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Re: Preprocess of HRV Analysis

hi,

Do you know how to use wavelet detrend.vi in HRV analyze.

Now, I don't know how to set threshold frequency and wavelet about this VI

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