Monster Kookies makes wonderfully fantastic anatomically correct heart pendants. Like this one:
They're sculpted in polymer clay, painted and embellished. I love how this one looks like clockwork. Others look like little scientific heart models, and one even looks like wood.
You can find these very cool hearts at the Monster Kookies Etsy shop, along with zombie cupcakes, clockwork birds and other cute-creepy things. Go look, it's fun. You can also find Monster Kookies work on deviantArt.