How is this done?

This is my first time here and I hope I am posting in the right place.

Does anyone know how this would have been created? I have looked for tutorials on it but haven't been able to find anything other than the folded heart effect.


Many thanks
What Paul said, it's gradients, for the internal one, select the heart and go to select > modify > contract and do it by like 10pixels. Then add the gradient (I think that's about right, I might be wrong about the menus).