Analysis of ECG signal

[marp84]

i've try to make the ecg signal processing from this site http://zone.ni.com/devzone/cda/tut/p/id/6349

but i've problem for QRS Complexes Detection that can't show. can you tell me why and how i solve this.

[nitin111]

how did you find the difference between two peaks??.....and what if the P wave or T wave is as high as the R wave...how will it differentiate between R peak and the other peaks??