QRS onset and offset

Hello! I am currently trying to fing a way to extract the QRS- Duration and I for purpose I implemented an Onset/Offset detection algorithm from a paper. It works only partaly and I am trying to find a better way to implement it, without getting into heavy math.

Do you have maybe a suggention how to to detect the onset and offset of the QRS-complex? assuming I can choose which records to use so there will be always S and Q waves.

[Ewunate Assaye Kassaw]

Hello dear! I hope you are doing well!

curently I'm doing on Time domain ECG feature extraction and I have got one challenge of detecting the onsets and ofsets of P, Q, S, and T waves. does any one can help me with this?

kind regards.

Answer 1

[Star Strider]

If you have a relatively recent version of MATLAB (R2017b or later), the approach in How to find QRS complex for this Graph? will likely work.

If you do not have specific Q and S deflections, this is more difficult, although definitely possibble.

[Ray_Li]

Q and S wave are presesnt, althouth I might have baseline wander in some records.

So the approach would be to find the Q and S minimum points and then find the points where the isoelectric line deflects near those minimuns?

[Star Strider]

That code specifically detects the Q and S deflections. Detecting the changes from the nearest isoelectric line (the beginning of the Q deflection and end of the S deflection, assuming no ST abnormalities) might require additional processing (such as the ischange function).

With respect to correcting for baseline variations, the approach in Correcting for baseline drift and determining the isoelectric line of an ECG would likely be appropriate.