A call at 11:47 p.m. last Friday changed the life of a 21-year-old Greenlawn man and his family for the better. On the other end of the line was a heart.

With tears of joy streaming down her face, Michele Martines gracefully accepted the heart on behalf of her son, Christian Siems, who was in desperate need of a transplant after suffering from congestive heart failure as a result of a genetic disease.

“We packed everything; we were running around scared trying to call people,” Martines said describing the moments after finding out her son would be getting a new heart.

Martines said she was overwhelmed with emotion as the moment she had been waiting for happened. She was happy and scared for her son, but she said he was ready.

“He was ready to go, ready to go, ready to go,” Martines said. “He wanted the heart.”

The quest for a new heart began on June 28, 2012, when Siems tried to donate blood at school. A nurse noticed he had an irregular heartbeat and suggested he see a doctor. His mom took him to the pediatrician, who suggested he see a cardiologist.

After having an echocardiogram, a test used to see how the heart is beating and pumping blood, he had to undergo an immediate test that showed his heart was functioning at less than 20 percent capacity. Doctors had to install a defibrillator, which delivers a dose of electrical energy to the heart, because Siems was at risk of cardiac arrest.

The condition was manageable with medication until last September, when Martines noticed something wasn’t right with her son.

“His heart started to fail,” Martines said.

Doctors found 80 pounds of fluid in his body as a result of congestive heart failure. He was rushed to Huntington Hospital and then airlifted to Westchester Medical Center in Valhalla, where he went into severe cardiac arrest.

“He was dying,” his mom said.

Siems underwent surgery and was living because a machine and a mechanical device helped his heart beat, Martines said.

Finally, in November, he was well enough to come home and his mom stepped in to tend to him as they patiently waited for a heart. While he was a priority on the donor list, some people can wait as long as 20 years, according to Siems’ doctor Alan Gass, the family’s cardiologist.

Gass said Siems was in need of a transplant and was lucky his wait was just months instead of years. Another factor helping the young man with his condition was his age, the doctor said.

“Young people can compensate well, even though they are getting worse quicker,” Gass said.

But while Siems was able to compensate, young people fall apart quickly, and his heart was deteriorating even though he was being treated for his condition. The need for a heart was vital.

On Saturday, just 12 hours after appearing at a press conference with County Executive Steve Bellone (D) in an effort to promote organ donation, Siems received the call that a heart was ready for him.

The family got into the car to drive to the hospital in Valhalla and anxiously waited for the surgery. At 7 a.m., the family said their goodbyes as Siems was wheeled off to get the heart he had been desperately waiting for.

While her son was getting prepped for the surgery, Martines was pacing back and forth, and ultimately she came in contact with the doctors who had her son’s new heart in a cooler. The small amount of doubt she had disappeared, as she said she knew her son was going to be just fine.

“I just couldn’t believe it,” she said. “It made it real that it was really happening.”

After a few minor complications and 14 hours in surgery, Siems’ new heart was in his chest and ready to go. And while he was unable to speak following his surgery, he used a pen and paper to let his loved ones and doctor know he was doing just fine.

“The best I felt in five years,” the white piece of paper read. The family teared up at the note. Siems’ dad, Gerald “Gerry” Siems, who was also a heart transplant recipient, died in 2013.

The young man is expected to stay in the hospital for roughly two weeks, according to Gass. In a few weeks, he will be able to return to a normal life, which entails playing sports and doing what he loves.

While Siems’ story ended well, the wait for organ donations may be far too long for some people. According to LiveOnNY, a nonprofit organ donor network, roughly 10,000 New Yorkers are waiting for various organ donations at any given time. On average, 18 people die every day while waiting for organ transplants in the U.S., according to the group’s website.

One donor can save and improve the lives of 58 people through organ and tissue donation. To learn more about organ donation, visit www.donatelifeny.org.