For some reason the ecg trace is unstable, often wild and unreadable except when I am still. I have asked a friend to use it as well with the same result. I am using it according to the instructions. I have to say it is not easy to understand the instructions on how to place the device on the chest and my friend, a woman of 5'2" in height found it was too large to fit her chest comfortably. Due to these problems I did not use it for many months and only in the past few days I have I tried again as I am cycling and want to record the ECG. Also, I was finding it switching off and on when in use. For me it does not work at all..it is unusable. CH
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