Samsung's latest smartwatch has an electrocardiography (ECG) sensor, but it is deactivated at present. The OEM had projected that it would be working via a firmware update in the first quarter of 2020 (1Q2020). However, it now seems it's going to miss this deadline.
https://www.notebookcheck.net/The-Samsung-Galaxy-Watch-Active-2-will-get-ECG-support-but-it-will-be-delayed.459230.0.html