When Dawn Grace’s teenage son Calen accidentally shot himself in the head, she felt angry, bewildered. She was certainly not inclined to donate her son’s organs.

And then he came to her in a vision. “Mother, what would I do?” she said he told her. “It’s not about you.”

Four years to the day that she lost her son, Ms Grace and her family travelled from their home Crofton, Kentucky, to meet the Nebraska man who had received his heart. She also got to hear it beating.

Calen Grace believed the gun he was playing with was defective (Family)

“I can hear it. It’s beautiful,” she said, listening through a stethescope placed on the chest of Joe Hansen. "It’s so peaceful.”

Mr Hansen, 55, of Council Bluffs, was born with a hereditary heart disease that doctors diagnosed as hypertrophic cardiomyopathy. Because of this, his heart muscle was abnormally thick, making it difficult for the heart to pump blood.

“I wasn’t able to do everything in my life kids my age were doing,” he said at a press conference on Friday, according to the Omaha.com. He began to suffer heart attacks, underwent surgery that failed to correct the problem, and by 2012 was facing some harsh truths.

Mr Hansen said he felt blessed by the organ donation (Omaha Medicine)

“He was in the very, very end stage of heart failure,” said Dr Eugenia Raichlin, Mr Hansen’s cardiologist at the Nebraska Medicine hospital.

Calen had shot himself in the head with a .22 gun he believed was defective. He had been playing with friends and trying to prove to them that the weapon did not fire. When she saw his body at the hospital, it had goose bumps and a heart beat. It was hard for her to believe he was gone.

Ms Grace went home to rest. She said it was then, that her son came to her as she slept. When she woke, she called the hospital and told them to go ahead and harvest her son’s heart.

While Mr Hansen and Ms Grace had spoken before, Friday’s event in Nebraska was the first time they had met in person. Mr Hansen showed a photograph of Calen that he keeps in his wallet.

“He is the very first thing I see,” he said. “We talk quite a bit. Because of Calen, I’m in college, I’m back to work. I try to honour his memory.”

Ms Grace said that four years ago, Mr Hansen, who had been bed-ridden, had received another chane. She said she believed her son had given the gift of life.