SAN MARCOS -- After undergoing transplants nearly six months ago, two San Marcos boys are now able to run, jump and play literally to their hearts' content.

"I feel better than ever," said 7-year-old Trevin Kremis, a second-grader at Knob Hill Elementary.

Trevin and his brother Richard Kremis, 11, suffer from cardiomyopathy, a genetic disease in which the heart's muscle fibers are enlarged and thick. The two boys received life-changing gifts this summer -- new hearts.

"Now I have a big chance of survival," said Richard, a sixth-grader at Woodland Park Middle School, who encourages others to consider organ donation.

"It saves lives," he said. "We were lucky enough to get (the transplants) when we did."

After having internal defibrillators surgically implanted last year to protect the boys from heart attacks, they were placed on the transplant list in April and underwent matching heart transplants at UCLA's Mattel Children's Hospital in June and July.

Both boys suffer from a form of the disease called hypertrophic cardiomyopathy, in which the wall between the two ventricles (pumping chambers) becomes enlarged, obstructing the normal flow of blood to the rest of the body, explained Dr. Gregory Perens, assistant professor of pediatric cardiology at Mattel Children's Hospital. Perens was a member of the transplant team that managed the boys' cases, in addition to pre- and post-care.

The disease, which affects about 1 in 500 people in the United States a year, results in shortness of breath upon exertion, dizziness, fainting and chest pains, according to Perens. The boys had a more severe form, however, that restricted their activities and put them at high risk for heart attacks or sudden death, he said.

"Before the transplant, we were living in the doctor's office," said their mother, Deanna Kremis, 38.

Now the boys can't wait to get home from school so they can run and play till sundown, said Kremis. Richard plans to join a soccer team, something he couldn't do before, while his younger brother rides his dune buggy every chance he gets.

"It's night and day to how they were before," their mother said.

Trevin said he likes to tell people the 8-inch scar in the middle of his chest is a bear scratch.

"Chicks dig scars," he said.

The disease runs in the family -- the boys' great-grandmother, grandmother and uncle all suffer from cardiomyopathy, but from less serious forms that have been controlled with medicine and pacemakers. Kremis herself was diagnosed with the disease in October and is expected to have an internal defibrillator implanted Jan. 7 as a precaution.

"I'm scared … I'm not as tough as my sons," she said. "(Richard) tells me, 'That's nothing mom.' "

While Kremis was told she doesn't need a transplant now, doctors said she may need one eventually.

She and her boys will head to the doctor's office again Monday to make sure there are no signs of rejection. Kremis hopes her insurance will come through for a new blood test that could indicate whether her 15-year-old son, Kyle, who has a nodule on his lung, would ever develop the disease.

"I don't think I'd be able to do it," said Kyle, a Mission Hills High sophomore.

The barrage of surgeries have put financial strain on the family, which has been living with Kremis' parents in their San Marcos town house since the end of March.

The family had to close its business and leave its home in Arizona to get the transplants, Kremis said. While her husband works, she attends to the boys' needs, and now her own.

Insurance statements indicate surgeries for the two boys are in excess of $1 million and bills come in daily, said Maureen Holden, the boys' grandmother.

"Their insurance has a maximum and they've exceeded it," said Holden.

The family pays roughly $500 a month out of pocket for each boy's medicine, said Kremis, adding that they each take about 20 pills a day.

She said the support of friends and family has been humbling. A few groups -- such as Girl Scout Troop 4085 in Vista, the Salvation Army and Mission Hills, Grace Lutheran and Emmanuel Faith churches -- have reached out to the family so it has something under the tree this Christmas.

"A lot of people have been very charitable," said Kremis. "It's a huge help."

Bonnie Williams, whose women's Bible study group donated gift cards to the family, said she and a group of friends who worked with Holden at Palomar College are sending letters to other charitable organizations in hopes of helping the family get back on its feet.

"We're doing what we can to help, but their need is ongoing," said Williams.

Contact staff writer Noelle Ibrahim at (760) 740-3517 or nibrahim@nctimes.com.

How to help

- To make a donation to the Trevin and Richard Kremis Fund, send donations to account No. 7885242078, Wells Fargo Bank, 145 N. Escondido Blvd., Escondido, CA, 92025