The question is not very clear. Why do you want to normalize the “period” of the ECG signal? In fact, this signal is not rigorously periodic. It is possible to detect the maximum points of this signal and to compute de duration between 2 successive pics Dtk. The mean value of these values can be considered as the “period” T of the ECG signal. Using this value it is possible to compute the Heart bit Rate: HR = 60 sec/T [beat/min]. The standard deviation of Dtk values can be used to characterize the Heart bit Rate Variation: HRV. For a normal person, HRV > 0.

Hi,

Maybe this article on some ECG compression approach is what you are interested in? 

https://www.researchgate.net/publication/7021142_An_Effective_and_Efficient_Compression_Algorithm_for_ECG_Signals_With_Irregular_Periods

Article An Effective and Efficient Compression Algorithm for ECG Sig...

normalization means referring to some ECG. You can refer to standard ECG signals and compare the ECG taken with that. however I doubt if there is a normal ECG signal. In such a case, normalization loses meaning. If there is a reference signal then one can compare the ECG taken with that, but the signal may have a different rate or frequency. In such a case, you have to expand the ECG taken or compress it before such a comparison can be done. Even assuming that you have done this and ensured that the rates are same, one doubts whether the rate will remain the same. So one is likely to get changes in rate between a reference signal and the ECG taken.  what a specialist does is to look at the characteristics of the signal and draw some conclusions. so it looks to me that one has to be clearer as to what one wants to achieve... Else, each answerer will take you in his / her way.I.e, interpret the questions as best as possible from their point of view. That includes me.

please look up this article and see if it makes sense to you.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.100.998&rep=rep1&type=pdf