**4. Datasets Description**

Taking into consideration the requirements outlined above (see Section 3), the following four datasets were chosen for the current study, namely: Lviv Biometric Dataset (self-collected), Physionet ECG-ID dataset, Physionet QT dataset (only some records with a normal sinus rhythm) and Physionet MIT-BIH Normal Sinus Rhythm. A short description of each of these datasets, as well as a comparison of the main parameters, is presented below (see Table 1).


**Table 1.** Basic parameters of the ECG datasets.
