LabVIEW

[Sco88]

Hello,

For our BME senior project, we are acquiring ECG signals from a person using sensorDAQ system and then analyzing the signals to measure heart rate as well as test for HCM. We've created a VI for measuring the heart-rate but the values that our VI gives us make no sense (1500, 721, 5000...). I've attached our VI with this message, can someone please take a look at it and tell me what we are doing wrong?

Also, we want to test for HCM in the ECG signals, indicated by an inverted T wave. How do we go about doing that in Labview?

Thanks a lot!

[Sco88]

I found a VI (attached with this post) in the LifeScience discussion forum which seems to do a very good job of calculating the heart rate. How do we modify  this to work with our sensorDAQ system?

Thanks! 

[tbob]

Good find.  Just double click on the DAQ Assistant Express VI and set the parameters to match your system.  For instance, set Acquisition Mode to N Samples, Samples to Read to 5000, Rate to 1k, add your physical channels to the Configuration tab, etc....  This VI does all your homework for you.  You should learn how it works by studying all the functions that it uses.

[Sco88]

Thanks for the reply!

However, I don't understand why we extract the waveform components and rebuild the waveform from output data from each filter and denoised waveform. Can you please explain that?

Thanks!

[Steve.J]

Hi Sco88,

You may also find some useful information, links, resources, etc. related to ECG acquisition and analysis on the NI Biomedical User Group website - check it out.

Steve

[tbob]

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Sco88 wrote:

Thanks for the reply!

However, I don't understand why we extract the waveform components and rebuild the waveform from output data from each filter and denoised waveform. Can you please explain that?

Thanks!

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That is mighty strange.  I don't see the purpose of extracting and rebuilding.  Just eliminate that part.

[Sco88]

Thanks for the reply! I've attached my modified VI with this post as well as an image of the front panel. As you can see, the heart rate values are really off (they go from 16 to 42 to 83). I believe that after obtaining a couple of values for the heart rate, we would average them out to get the final value for the pulse which we can use for further analysis.

Also, the denoised waveform (yellow line) is the final waveform that we want to display for our project. However, it seems that the amplitude of the signal is being reduced because of the filters and detrend/denoise functions. Why does that happen?

 Any ideas on how to look for an inverted T wave within this signal to test for HCM?

Thank you!

Sco88

[tbob]

Sorry, its been too long since I worked with heart waveforms.  Also, I can't run your vi because you have subvi's that are missing from my system.