The Polar OH1 can be used instead of an ECG device, eventually also in non-athletic research applications. Polar keep selling it for research applications.

According to this paper, the Polar OH1 can be used instead of an ECG device for moderate and high intensity physical activities: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217288 and eventually also for non-athletic research applications, what means, that the accuracy of the Polar OH1 is sufficient to replace an ECG device. A Polar OH1 paired to a Garmin watch can …