Melissa Russom and her sister Christi were inseparable. 

"We were sisters [but] were also great friends," Melissa said.

Christi was known as the social butterfly, born two years prior to Melissa. The sister says she always looked up to Christi. 

"She was the person who I loved the most, but also the person I fought with the most," Melissa said.

Melissa never expected the bond between them would be ripped away. In 2005, Christi collapsed and died at 24 years old. 

"I was expecting to grow up having babies together and you know, doing family things together," Melissa said. 

However, following Christi's passing, Melissa still could not figure out why. 

"About a week after she died I was tested because they had to figure out what's going on here. Why did this happen? Could it be something in the rest of the family?" Melissa said.

Melissa learned she had Long Q-T syndrome, a rare heart disorder that impacts the heartbeat. Her mother, aunt, cousins would all be diagnosed in the coming months. 

A decade later, the diagnoses resurfaced and struck the next generation. 

"My daughters were actually diagnosed in utero," Melissa said.

Melissa says it's a manageable disease if it’s found early. A new study shows around 50 percent of Americans have some sort of heart problem, which often goes unnoticed until it's too late. Melissa says the disease does not discriminate.

"To me at 22, my face wasn't the face of heart disease. Certainly my two and four year olds wouldn't have been the faces of heart diseases if I could look into my future," Melissa said. 

The girls will go on to live mostly normal and healthy lives. 

"We tell them sometimes, 'hey you have a special heart.' Of course, Cora says 'oh like the grinch has a special heart.' You know, because his heart grows at the end. We try to put it into terms they understand," Melissa said.

The family now volunteers for the American Heart Association and organizes events in Christi's memory. Through Christi's death, Melissa says she gave the women she loved the most a chance at life.

"I love that Chris lived her life without fear. But at the same time, if we had that piece of awareness she'd still be living fearlessly," Melissa said. 

To more about the dangers of heart disease, visit the American Heart Association website.