.lvm and .tdms files not read on ECG Feature Extraction Tool

[dha82]

Attached are some files that are the voltage output from a piezo circuit to collect heart beat. ECG Feature Extraction tool not working or reading these files

any help appreciated.

Thanks,

Daniel

[ZJ.Gu]

Hello,

I have a look at your files. It seems the tdms file you attached here is too short and not feasible to do feature extraction. And unfortunately, your LVM (generic txt type) is not supported in the current starter kit.

There is a workaround. You could use "Read from Measurement" to read out the data from your LVM file and use TDMS write to export the data to a tdms file which is supported by starter kit.

Another problem in your data is that your signal amplitude is too small (0.1 or so). It may be too small for a human. Is it from human ECG?

I attach the tdms which I converted from your LVM and have a 10 gain on the data.

Thanks!

ZJ Gu

[dha82]

Hello,

I think I only recorded about 40 seconds worth of data but ECG extractor should still detect the QRS peaks.

Those uploaded files are slightly older ones, I have since magnified the voltage by 10 to increase the signal amplitude but ECG Feature extractor still does not read the whole file, only 0.5s. If you open the lvm or tdms using notepad then copy and paste into MATLAB and plot, you can see a nice ECG signal.

It is from human ECG (my own!) using a piezoelectric sensor that is not very thick so you get a small voltage. Increasing the thickness of the sensor will help increase the charge created on the surface of the sensor and so will give a larger voltage signal. The graphs in LABVIEW have a magnifier setting which I have found is helpful to increase the voltage and see the peaks more clearly.

Is 'Read from Measurement' a tool? I'll give that a go

All I am after is the RR interval data, time between each peak. Is there some wavelet analysis tool that may find it?

Thanks,

Daniel

[ZJ.Gu]

Hi,

"Read from Measurement " is a function on the palette of "File I/O".

If you convert your data into tdms, it will read all the data. Did you try what I attach above in ECG Feature Extractor? Although the other waveform may be not detected correctly due to the big noises, the RR interval is correct:

Then "Export RR" to HRV Analzyer for HRV analysis.

Thanks!

ZJ Gu

[dha82]

Your tdms file works but my problem is tdms file that I create from the datalogger into DAQ assist does not seem to work in the ECG extractor. In my first post above, I put up a tdms (HeartBeatDataGd.tdms) file and that does not seem to be able to be read by the extractor, I think its due to there being a time column.

I am finding problems with the voltage being too small. How did you magnify it?

Thanks heaps,

Daniel

[ZJ.Gu]

Hi,

HeatBeatDataGd.tdms is too short.

For the magnification, you could load data then mutiply by 10 or other factor.

Thanks!

ZJ Gu