This is one of the symbols included in Unicode because it is part of the hugely popular Zapf Dingbats. Hermann Zapf designed the symbols in the 1970s. Now, many of these symbols are generic symbols that have been used before, but it seems to be some are Zapf's original creations. One would have to research whether the heavy heart exclamation mark was ever used before Zapf included it in Zapf Dingbats. Perhaps other Typophiles have more information.

Thanks Jongseong. Went straight into a meeting after posting that, and your info came in very handy! Thanks again.

Irene