Suggestions for Automatic Classification of Morphological Heart Arrhythmia

Hi Mehrdad,
This is going to be a rather long message. I found your project really exciting and I have lots of questions.
Some initial cosmetic suggestions that I would like to get across are as follows:
1. In a line or two, right at the beginning you might want to mention that heart arrhythmia is an irregular heart beat. Also which type of arrhythmia are you trying to classify or model? Bradyarrythmias or tachyarrhythmias?
2. You might want to add the definition of QRS complex (maybe in brackets where you first mention it) even though i noticed you did include it in your figure but it might not be very obvious.
3. Right above your gaussian section, there is no link to click for further information on Hermite basis functions. Same for the Gaussian function ,the KNN algorithm and neural networks.

Questions that came up in my mind as I was going through your page are outlined below:
1. How did you chop the continuous signals into units containing only one peak? Also, does this mean you extract more than one peak from each patient’s 30 minute ECG signal?
2. Is it possible for you to show how you remodelled the 203 intervals to 25 intervals and what was your resulting weighted vector for the combination of Hermite basis functions?
3. Using k value as 1 makes me a little uncomfortable. Isn’t it true that larger values of k reduce the effect of noise on classification? Do you think, using k=3 or 5 would improve your results?
4. The N training vectors that you are using are continuous variables? Or are they discrete y values at each of the 25 intervals? Would i be right in assuming the dimension of each training vector to be [1x25].
I really found your project very interesting and I think you’ve done a very good job explaining your problem description and the hypothesis is also very clear. You could probably add some more input to how you model your problem (for instance you could write your x,k_i and y vectors explicitly. I am really looking forward to you Neural network implementation and how it wold compare to this 1-KNN model as it seems almost everywhere neural nets are taking over.
Regards,
Ritika

Hello Ritika,

Thanks for your very useful comments. I have already fixed the links. I would certainly add the demanded information regarding the heart arrhythmia and my modelling for the next draft.

Thanks,

Mehrdad Ghomi