How to Append or Bind to a Heart?

I, like many others, am making a custom heart icon like the in-game poison, wither, or freezing hearts and I'm curious if there's any way to append a texture to the hearts like those three do. I know that I could just have an overlay over where the hearts are, but the hearts are animated and I'd like for my custom heart textures to follow those animations. I'm completely fine with having to do some manual coding if that's what it takes.