The first line of this article calls a heart that spontaneously heals itself "miraculous." And indeed, it sounds that way. But further down in the article we get the real explanation:
Um said doctors seem to be seeing more cases similar to this, in which a failing heart heals itself.
"The interesting thing is that if he had gotten a transplant right away, we would have never known if he could have recovered on his own," Um said. "Now that we have technology that allows people to remain on external heart machines longer, we could see this more."
In the simplest terms, Dr. Um explained, the heart got sick, triggering an immune response that shut the heart down to fight the infection, and eventually healed itself. Technology kept Crowe's body alive while his heart healed.
So it's not a "miracle," it's yet another benefit of modern medical technology. Not quite the same thing, is it?