Open-minded can be akin to openness, being open to new ideas. Similarly, being open-hearted is being open to kindness and love and allowing that (or more of that) to come into your life, your being.
Conversely if you are closed-minded, your state of being would be contracted physically, mentally, emotionally, and spiritually. Likewise, if you are open-hearted, you are expanding, metaphorically of course! ;) Energetically, people can feel or sense this about you.
How does openness show up in your life? What are you (most) open to?
Photo of me (years ago) at a fashion show