HRV spectrum

[Majjo]

Hi,

I try to do the HRV spectrum from ECG signal. I find R peaks, calculate R-R intervals then resample R-R intervals and connect these intervals to the AR spectrum and the FFT spectrum. When I do it the result is for AR spectrum different and the range is so weird too. The FFT spectrum is complete out of line. I don´t know what I am doing wrong. I am attaching a picture of front panel and block diagram.

Thank you for your help.

[Haier_Xu]

Hi,

The R-R intervals series calculated from the R peaks is not evenly sampled, so it is not correct to resample it by using the TSA Resampling (Equal) instance, which is used to resample the equally sampled time series.

Actually, HRV FFT/AR Spectrum VI in Biomedical Toolkit provides the instance for unevenly sampled RR. You can just select the Unevenly Sampled RR instance from the Polymorphic VI Selector and connect the raw RR intervals calculated from the R peaks to both the RR and Raw RR terminals. This VI instance will help you interpolate the raw RR intervals to an evenly-sampled time series. BTW, you can remove the trend from the RR intervals so that the range of the PSD results will be smaller. The attached snapshot shows you how to use these VIs. 

Please refer to the HRV Analyzer example under National Instruments\LabVIEW 2012\examples\Biomedical\Biosignal folder for details.

Thanks!

Haier Xu