When entered in separate columns, both values filter into the HR column. (see 4pm and 6pm below)

When entered in the same column, as in the 8pm case, 21 was entered in Pulse, then 44 in Heart Rate. The 44 is preserved in HR. 

Whichever value is entered last is the one that would be displayed in ezyVet.

Here's the Smart Flow sheet from those 3 times:

One more example, where Heart rate was entered, then Pulse was entered.