How can I Identify the P,Q,R,S and T waves in all 12 leads of ECG

Hi all,

I am currenly working on diagnosing heart diseases using 12 lead ecgs.

for this project i use preprocessed data which has 500hz sampling rate.

Here i attached a sample file from the database i used.

as a first step seperated the 12 leads ecg

Data = load('HR00001.mat');      % 12x5000 double
ecg = Data.val(1,1:5000);           % 1x5000 double

my next step is to identify the P,Q,R,S and T waves. As a beginner i found it quite challenging.

I wrote a code which only able to find R waves in the lead I but its totally useless when it comes to other leads.

Can some one help me a step by guidance for detect P,Q,R,S and T in different leads.

Data = load('HR00001.mat');      % 12x5000 double
ecg = Data.val(1,1:5000);           % 1x5000 double

peaks_1 = ecg>500;
f_s = 500;

time = (1:numel(ecg))/f_s;
[peaks_2,pos_peaks] = findpeaks(ecg,'MINPEAKDISTANCE',10,'MINPEAKHEIGHT',500);
plot(time,ecg,'b',pos_peaks/500,(peaks_2),'ro')
axis ([0 10 -300 800])

Please help me in this issue . your help will will highly appreciated.

thanks and best regards.

[John D'Errico]

Be serious. This is not a question about MATLAB, just a request for someone to provide source code so you can do your job/task/project, whatever. And that is not the purpose of Answers.

Instead, you probably need to hire someone to do your work, or at least act as a paid consultant. And that also is not the purpose of Answers, to act as a bulletin board where you advertise for services.

So find someone, perhaps in your local university, who will be willing to provide this service. Or, you can get paid support from The MathWorks. In either case, you will need to "sit" down and carefully explain what you are trying to do. Be clear, be specific. Otherwise, expect poor results from any such relationship. Of course, a good consultant will know how to push you for the specifics. If they do not, then keep looking.

Really in the end, you will be best served if you learn MATLAB sufficiently so you can do that work yourself.

[Naveen F]

Hi John D'Errico,

I am really sorry if i pitched my question in a wrong manner,

I mistakenly mentioned asking a code. I know there is no such code for my requirement.

I thought their a re in-built functionalities in matlab to detect waves. After your reply only i reallize the weightage of the question i asked.

basiccaly i need a good explanation or a step by guidance or a reference to detect P Q R S and T Waves using matlab software.

I have followed this code,

https://www.mathworks.com/matlabcentral/fileexchange/66098-ecg-p-qrs-t-wave-detecting-matlab-code

It really helped me for get a basic understand about peak detecting.

But when it comes to scenarios like 12 leads i am not that aware how detecting is working.

thanks and best regards.

[Star Strider]

This problem appears frequently, and does not have a universal robust solution. With sick hearts, the P-deflection may not be present (consider atrial fibrillation), and with intraventricular conduction problems, it may be difficult for a computer algorithm to define even a R-deflection, much less a QRS complex. (This is the reason Board-Certified Cardiologists ar so well compensated. For the record, I am not one.) See Braunwald’s Heart Disease, considered to be the definitive reference, for a complete, relevant discussion.

[Naveen F]

Hi Star Strider ,

That so true sir, I tried lots of proposed codes in the matlab forum but the problem that i am going to address is quite complex one. I really appreciate your guidance.

I access the source ( Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine ) from google scholar since the website you have mentioned is currenlty not working or it blocks the IPs from my region . I hope this will help me to solve my issue.

Thanks and best regards.

[Star Strider]

Naveen —

My pleasure!

I have a hardcopy of the latest edition in my physical library. If you are doing anything related to heart disease, I suggest that you get a copy or refer to one in your university library It is an invaluable resource.

[Naveen F]

Thank you very much for the suggestion Star Strider sir, I will deffinitely send an email to our uni librarian regarding this resource.

Thanks and best regards.

Answer 1

[Cris LaPierre]

If you would like an interactive way to try to detect peaks, I suggest using the Find Local Extrema task in the live editor. It allows you to use a graphical interface to set the peak detection parameters. Once you get something you like, you can convrt the task to code, which allows you to build a script to run on multiple data sets.

It might be important to set your expectations here. This is not a silver bullet. You will still need to gain an understanding of what it is doing to use it appropriately, especially if you are trying to make medical diagnoses from your analysis.

[Naveen F]

Hi Cris LaPierre ,

Thank you very much pitching your answer for my question. I know nothing comes on a silver palate. I'll put my fullest effort on this and find a way to solve my problem using this method. I hope this method will help me to solve my issue.

keep up the good work.

Note : Still i can ask any follow up questions regarding this problem right even after i accept this answer ? (just ask because i am new to this forum )

Thanks and best regards.