The Polar OH1 has been validated in a PLOS ONE paper as far accuracy is concerned: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217288 The authors found a 95 % – 99 % agreement between a g.Nautilus ECG device and a Polar OH1. The 64 channel g.Nautilus device costs according to a g.Nautilus demo video at least 50 000 USD. There is …