Make the case for the significance of HRV - human heart is not a clock, certain variability is healthy. Offset from this variability is clinically significant. Too much variability may indicate arrhythmia and too little may indicate heart problems. In athletic training smaller than normal HRV parameters may indicate overtraining. 
Therefore accurate HR detection and HRV calculation are important. A wearable device can record HR and HRV continuously. 
HPM is capable of independent functionality as well as under direct control of the host. Host software receives, records and displays the ECG signal and other signals acquired by the HPM.