They were originally BioHEART (BHRT) but their research led to over 30 protocols expanding waaaaay beyond just "heart issues" so in late 2015 (I think that was about when??) they re-named to U.S. Stem Cell Inc to show a broader appeal - that they just don't treat "heart conditions":
WATCH THIS ONE FOR STARTERS FOLKS :
BIOHEART (BHRT) now = $USRM AFTER NAME/SYMBOL CHANGE = SAME COMPANY !!