ECG: RSA (respiratory sinus arrhythmia)

[DominiqueMakowski]

Aim:

• Compute RSA

[DominiqueMakowski]

Here I was, thinking about the zero crossings again, and then I realized that it does not indicate the proper locations of respiratory cycles. From what I understood, a respiratory cycle is divided into 2 phases: inspiration and expiration. The former starts when the signal is a its lowest and the second when at its highest. Thus, a rsp cycle starts and ends at every lowest points of the signal.

Here's the current zero-crossings returned by biosppy:

However, I have the feeling that indicators of RSP cycles should be like this:

@rhenanbartels what do you think?

[DominiqueMakowski]

I added the rsp_process() function (previously included in ecg_process). This computes the proper cycles onsets (and more: a "continuous" phase (inspiration and expiration) marker (see plot below), some respiratory variability indices (to be developped) and such).

The code for this plot is available in our test bed 😆

[DominiqueMakowski]

Ok, I've reworked the RSA function. It extracts several indices (mean RSA, variability, and the unfamous continuous RSA signal 😛)

We can then plot the RSA evolution (see the purple line).

I think we're good to integrate it within ecg_process 😸

[DominiqueMakowski]

Done: ecg_process

Tell me what do you think