How do you detect QRS complexes in an ECG?

[Laudie3a]

We are trying to detect a QRS complex in an ECG signal but are having problems with it. We know that the ECG is reading by the first Waveform graph but when it runs through the Multiresolution Analysis Express VI there is nothing that is being detected (as shown by the second waveform graph). I have a feeling it has to do with the settings of the express VI but I am not sure. Could someone please help? I have attached the code to go with it.

[Coq_Rouge]

First of all. Why are you using this complex method? It seems to be an overkill. Do you understand the concept used in this program;) Since I do not have any data I can not test your setup. But the Express VI expect the waveform data type not an array. So the sample rate information is lost. For the Express VI this is not important, but the sample rate information is used in the peak/valley detection so it might have some relevance.

Also how is your data quality? Can you post some pictures(screen shot) showing your data?

[Coq_Rouge]

One more thing. In your VI it has sample rate equal 10Hz as default. This way to low. If this human ECG use at least 1KHz as sample rate.

[Steve.J]

You can also download the free NI Biomedical Startup Kit which has tools for ECG analysis (source code available on request) - see the details on the NI Biomedical User Group pages here

[Laudie3a]

Hey CoqRouge,

   I don't necessarily understand the concept of this express VI. Our professor said that we could use pre-made codes and I found it on this website: http://zone.ni.com/devzone/cda/tut/p/id/6349 so I figured it would work. We are taking 1500 samples at 250 samples/sec, which is what our professor told us to do. And we are getting clean ECGs read. How do we get the signal in without it being in the form of an array?

[Dennis_Knutson]

You don't seem to understand what is on your block diagram. You have converted the DBL array to a waveform data type and passed that to the DC/RMS function. It is the waveform data type that you should be passing to the rest of the functions so they have the dt information.

[Laudie3a]

Yea we figured that out and we changed the input to the express VI from the output of the build waveform but it still doesn't read anything. It will read the ECG but the reconstructed signal was just a straight line.

[Coq_Rouge]

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Laudie3a wrote:

Hey CoqRouge,

   I don't necessarily understand the concept of this express VI. Our professor said that we could use pre-made codes and I found it on this website: http://zone.ni.com/devzone/cda/tut/p/id/6349 so I figured it would work. We are taking 1500 samples at 250 samples/sec, which is what our professor told us to do. And we are getting clean ECGs read. How do we get the signal in without it being in the form of an array?

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First of all. The Express Vi seems not to do you any good. And you have now clue of what it supposed to do. So why not just remove it. If you just want to do some calculations to find the heart rate. Go to help in the toolbar, then select "Find Examples" and search for peaks. Your signal looks OK for such analysis. But you can improve it increasing the sample rate. But then again since your professor has not told you to do so, you will probalby not not do it. "D'oh!" as Homer Simpson would have said

[Steve.J]

Hi Laudie3a - what school are you with?  I'm curious about which schools are using LabVIEW for biomedical teaching/projects.

thanks,

Steve

[Bik3r]

Hello guys!

Excuse me being so unpolite, and disturbing your group discussion, but I would like to ask for some help from you. I saw the project posted by Laudie3a's , and it's exactly the project that I got at the faculty. I would like to ask you if you can help me out with those VI's: SensorDAQ_Setup, SensorDAQ_Modify, SensorDAQ_Start, SensorDAQ_Read, SensorDAQ_Stop, namely by telling me if they were custom made, or they can be found in the NI-DAQmx subpalette.

Thank You !