90.17 Generally accepted highly accurate ECG reference devices for accuracy studies for consumer grade heart rate monitors?

We have intensely reviewed potential ECG devices which can be used as research grade ECG devices for studies of the accuracy of consumer grade heart rate monitors, from Bitalino ECG, Scott Hardens PhD. MD. Sound Card ECG, AD8232 & ESP8266 ECG, etc. We came to the conclusion that a main problem that there is no …