Sept. 2, 2011 -- While it may be just another football season for other players at Central Catholic High School in Portland, Ore., it's a blessing for running back Hayward Demison III.
Last September, Demison collapsed on the field after scoring a game-winning touchdown. His heart stopped, but a nurse in the stands got it pumping again.
"It's an amazing comeback," Demison told ABC affiliate KATU at one of the team's practices. "God has just been blessing me throughout the whole process."
Doctors discovered Demison had a defect in his left coronary artery that blocked blood flow. They later operated to correct the abnormality but weren't sure Demison would be able to play again.
But a year later, Demison took the field during practice once again.
"It healed fine. It took like five months for my sternum to heal, and I was like good to go after that," he said.
Not Always Able to Play Again
Neither Demison's cardiologist nor his cardiac surgeon were available to speak to ABC News. Other experts not involved in Demison's treatment, however, said Demison's heart abnormality was extremely rare. It would not have been picked up during a routine screening.
"It would have been improbable to pick up unless he had presented with chest pain or had undergone a stress test," said Dr. Phil Ragno, director of cardiovascular health and wellness at Winthrop University Hospital in Mineola, N.Y.
"If a teenager has a heart attack, the causes are really different than what they would be if an older adult had one," asid Dr. Steven Lipshultz, chairman of pediatrics at the University of Miami Miller School of Medicine. "The majority of times, adults have atherosclerosis, or a blockage of the arteries."
Depending on the degree of damage to the heart and the cause of the heart attack, it's very possible to recover and participate in sports once again.
"When it does happen, it's relatively straightforward how you deal with it," said Lipshultz. "You take the coronary artery and cut it from where it's connected and stitch it where it actually should be."
After that, Lipshultz said, the amount of damage to the heart muscle and other health conditions that might contribute to additional problems may determine whether the young athlete can return to sports.
One of the leading causes of sudden death in young athletes is hypertrophic cardiomyopathy, or a thickening of the heart muscle. It can cause a potentially fatal irregular heartbeat.
Young athletes who are treated for this condition are likely never able to participate in sports again, Lipshultz said.
Demison's youth and level of physical fitness also helped his recovery, but he still needs to be diligent about his health habits.
"The things that are going to keep his surgery functional are a healthy diet and exercise," said Ragno. "He had a bypass operation, so he'll need frequent evaluations with his cardiologists and probably yearly stress tests while he continues to participate in sports."
According to the Oregonian newspaper, Dr. John Iguidbashian, Demison's surgeon, said in a press conference after the operation last year that most patients who have the same condition die before they receive medical attention. Demison knows how lucky he is and says he feels better than ever.
"I feel like I was 10 times greater than I was last year, because last year, it was like ... a little tired and dizzy," he said. "Now, I'm just like full go."