Yes, I would say that both are roughly the same. "Change of mind" might imply a more logical (versus emotional) decision. "Change or heart" might imply more of an emotional (or more significant) decision. Both phrases talk about changing a decision. Examples: I was going to go to the movie today, but I changed my mind. I was going to study to be a movie actor, but I've had a change of heart.

They are interchangeable such that if you use one rather than the other, everyone will understand what you mean. However, 'a change of heart' generally reflects change in a belief, emotion or emotionally-charged opinion. 'A change of mind' generally implies a change in an opinion or an action that was going to be, or in the process of being performed. For example: Fernando had a change of heart about the child's plight after hearing his story. And: I was going to go to the grocery store, but I changed my mind.

Often interchangeable. But there's often a subtlety in them. Change of mind often referring to a logical or rational approach. Change of heart referring to a more emotional one..