The person with heart rate over 150 BPM probably cannot hold the ECG Primer device steady (sorry, just kidding).
Actually, I was setting a temporal inhibition window after detecting the QRS wave to prevent the high T-wave mis-triggering the heart rate detector. The 150 BPM is arbitrary set by taking the half of normal RR-interval. Because the normal heart rate is 72 BPM and the heart rate for half of the normal RR-interval is 144 BPM. So I used 150 BPM. However, there is no reason to prevent shortening the window to cover the HR up to 200 BPM.
Jingxi Zhang
