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A miraculous thing happened the day Michael Crowe was set to receive a potentially life-saving heart transplant. Doctors had determined the surgery would be ineffective - but his heart suddenly started beating again.

Crowe, a 23-year-old pharmacy student from Omaha, had been diagnosed with acute myocarditis, or inflammation of the heart muscle, likely caused by a viral infection. When his mother brought him to the emergency room at his local hospital on Aug. 14, doctors found his heart was only functioning at about 25 percent efficiency. The hospital referred him to the Nebraska Medical Center, and by the time he was admitted to the intensive care unit there, his heart's efficiency had dropped below 10 percent.

"If he had come to us any later, his heart would have just stopped," Dr. John Um, Surgical Director of Heart Transplantation at Nebraska Medical Center told ABC News.

Doctors hooked Crowe up to a heart-lung machine that would essentially act as his heart for him, pumping blood throughout his body.

"When the heart stops, that's defined as clinical death," Dr. Um said. "In this case, his body only stayed alive because the machine was pumping his blood for him."

Crowe was immediately placed on a list for an emergency heart transplant, and remained on the heart-lung machine in a medically induced coma until an appropriate donor heart became available.

After nearly three weeks, a heart was found. The good news was followed by bad, though: tests revealed he had contracted a blood infection. Doctors said he probably would not survive the transplant surgery.

About an hour later, one of his doctors noticed something strange - his blood pressure was going up, something that would be impossible if his body was only receiving blood through the machine.

"His heart started working again on its own," Dr. Um told ABC. "The left side of his heart was pumping blood again. The right side was still weak, so we slowly eased him off the machine. At this point, he was in pretty good shape."

Dr. Um said this was the first time one of his patients has been on an external heart-lung machine for this long before his heart started beating again.

"He's home now, doing great," Dr. Um said. "He's really, really lucky."

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.

Although there could be effects on his heart in the future, Dr. Um said young people who suffer from acute heart problems like Crowe's tend to make a full recovery, healing fully.