How to convert a RR interval file into text format.

Dear Colleagues,

I want to use some RR interval files freely available at Physionet.org. In order to use it in my script which uses the function msentropy.m (also from Physionet) I need to convert this RR interval files (annotation files) into a text file format. I have tried to do it by copy and paste and so on. It did work somehow for annotation files containing just few columns and rows. But normally annotation files of RR interval files have 6 columns and could have easily 100-200 rows. I have tried many things but I just can not do it. I have also read the tutorials at Physionet but it does not work. Could someone help me in this matter? I would be very thankful for any help and guidance. Kind regards, Massilon

Answer 1

[Star Strider]

Not knowing what your files contain (other than that they appear to be a matrix of numbers), or what format ‘msentropy’ requires, the dlmwrite function would seem to be appropriate.

Experiment to get the result you want.

[Massilon Toniolo da Silva]

Hi Star Strider, many thanks for your reply. Unfortunately, I am not getting the expected results. The RR interval time series ( beat annotations files ) available at Physionet.org are already in txt format. But, when I work with them in Matlab I keep getting errors. I then thought perhaps I could used your proposal to convert (once more) into txt file so that Matlab would accept. When I open these files I can see there are 4 columns and 100-200 rows. I only need the second column but all rows. I need a N-by-1 matrix for the function msentropy ( from Physionet). I do not know anymore what to do! Could you please help with this issue? Many thanks! Kind regards, Massilon

[Star Strider]

My pleasure.

You first must import the text file into MATLAB. The dlmread or textscan functions can do this.

If you only need the second column, and you read the text file into a matrix called ‘Data’ this works:

Col2 = Data(:,2);

Then pass the ‘Col2’ vector to the ‘msentropy’ function.