What I noticed from the literature is that for automated heartbeat classification ECG segmentation is an essential pre-processing step.
However, I wonder that they are fixing the same beat length for all types of heartbeats such as normal,PVC, APC, paced beat etc. In practical situations, how far it is advisable?
Next, from paper to paper segmentation lengths are different then how can they compare their results with others?
If it is desirable to fix the length of a segment why can't we choose a window that covers P, QRS, T events rather using fiducial points?