(NEW YORK) -- Suitulaga Hunkin was just 26 years old when he learned that his heart had worn out.
He went to the hospital believing he was suffering from heat stroke, only to end up being diagnosed with cardiomyopathy. His heart had been stretched out and weakened, and, unlike a rubber band, it could not simply snap back into shape.
Weighing in at approximately 300 lbs, Hunkin knew he was technically overweight but thought he had been relatively healthy. He did regular weightlifting and spent 10 hours a day working as a plumber. Even after his diagnosis, Hunkin said that because he was young and naive, he didn't understand just how serious the situation was.
"It was crazy. I was in denial. I was like, 'Oh, you know that this is nothing. This'll be all right,'" said Hunkin.
Once he was diagnosed, Hunkin had to quit his job and could no longer work out. He spent his days stuck at home and quickly began to gain weight, reaching 350 lbs.
"Being in heart failure, it sucks," said Hunkin. "You walk fifteen steps and feel like your heart was going to explode."
Hunkin, a father of four who is of Samoan descent, said that his upbringing included plenty of high-calorie, salty meals. He had always begun each day with a hearty breakfast.
In the years after his diagnosis, Hunkin's health continued to deteriorate. After he had a small stroke, doctors found that Hunkin's heart was so damaged he needed a VAD (Ventricular Assist Device), a small mechanical pump to help his weakened heart.
While the machine bought him time, it did not cure him. A year after the device was implanted, it had to be replaced due to mechanical problems. It was then that Hunkin's cardiologist Teresa De Marco, the director of Advanced Heart Failure Program at UC San Francisco Medical Center, sat him down and told him that unless he got into shape and had a heart transplant, he would not survive.
"She said, 'You're killing yourself,'" recalled Hunkin. "[She said,] 'Do it for your wife, do it for your kids, but do it for yourself.'"
Since there wasn't a transplant doctor at the UC San Francisco Medical Center at the time, De Marco called different transplant centers to see if anyone would take him. No one would agree to operate on him because of his weight.
There are many reasons for an obese patient to be ineligible for a transplant. The operation is taxing on the body, and finding a matching heart is nearly impossible for obese patients.
"Obese patients, it's difficult to find a match," said De Marco. "The metabolic demands are higher when you're obese and it's hard to find donors who are within that range."
In order for Hunkin to be added to the transplant list, his doctors said he needed to get his weight down to 250-270 lbs with a BMI of approximately 35.
With the support of his doctors, Hunkin began to change his eating habits and to walk. He started with 10 minutes a day, up and down an alley near his house.
"It's like an addiction when you lose weight. The first 10 pounds come off, before I knew it I'm down 30-40 lbs," said Hunkin. "We had a new heart surgeon at UCSF, [Georg Wieselthaler]. He said, 'You know, I'm really happy you're losing the weight. You lose 20 more pounds and I'll transplant you.'"
Wieselthaler, the program director for cardiac transplantation at UCSF Medical Center, said that Hunkin's positive reaction to the VAD pump meant he was able to become more and more active, which helped him lose the weight.
"All of sudden you have exercise capabilities you didn't have before. To me that's an essential part of the whole story," said Wieselthaler. "Without that pump, he never would have been to do that."
After losing over 100 lbs to reach a weight of approximately 250, Hunkin was added to the transplant list and received a new heart on Aug. 8, 2012.
"I'll never forget that day. 'They said, 'We're putting you on the list,'" recalled Hunkin. "I dropped the phone."
After his surgery, Hunkin recovered quickly and was even able to walk a few steps around his room the day after his surgery.
Wieselthaler said he believes that with the new heart and a carefully regulated drug regimen, Hunkin has an excellent prognosis.
"We learned a lot over the last 30-40 years with drugs that can help suppress rejection of certain organs," said Wieselthaler. "We tailor immune suppressant medication for each patient. By doing so, we have excellent long term results."
In the six months since his operation, Hunkin has kept the weight off by walking and doing small toning exercises multiple times per week.
Copyright 2013 ABC News Radio