Doctors pronounced Sammy Berko, 16, dead after performing CPR for two hours. Now his mother is advocating for kids' heart screenings

Sammy Berko climbed to the top of a rock wall, rang the bell – then went limp.

The 16-year-old from Missouri City, Texas had gone into cardiac arrest and was pronounced dead following two hours of CPR. Five minutes after that, he suddenly came back to life.

Sammy was soon diagnosed with a genetic heart condition called, Catecholaminergic polymorphic ventricular tachycardia (CPVT), which causes sudden arrhythmias in otherwise healthy children. The rare disorder affects about one in 10,000 people, and left untreated, it can cause a heart to stop.

His 10-year-old brother, Frankie, had also died suddenly in September 2019 — and subsequent DNA testing revealed that Frankie, Sammy and their mother, Jennifer Berko, 45, all have CPVT.

“It’s a very shocking diagnosis,” says Jennifer. “What we've been told about CPVT is usually your first cardiac arrest is your last.”

Now an advocate for children's heart health screenings, Jennifer, a former TV news anchor, is sharing her family's story with PEOPLE because she believes the condition may not be as rare as people think, since many don’t know they have the condition until it’s too late.

“No other family should ever have to go through what we have been through,” says Jennifer. “There are way too many children, walking around with heart conditions and have no idea. And at any moment, their life could be ripped from them.”

Related: Buffalo Bills' Damar Hamlin Suffered a Cardiac Arrest — Here's How That's Different From a Heart Attack

“A miracle.”

On Saturday, January 7, 2023, Sammy's parents took him to the gym to climb with friends. When he went limp, his friends thought he was joking and threw their hats at him. But he didn't move.

A radiologist happened to be there when Sammy collapsed and performed CPR until the ambulance arrived and rushed Sammy to Texas Medical Center where doctors continued trying to save him.

At 6:35 p.m., doctors pronounced Sammy dead and told his parents to say goodbye to their son. “They said, ‘We’re so sorry, we can’t do anything else,’” remembers Sammy’s father, Craig Berko, 47, a sales consultant.

Jennifer remembers telling Sammy how much she loves him, and how proud she was of him. "I prayed," she says. Craig says he just stood there staring at his son in disbelief.

Then, suddenly, he saw his son move. Craig screamed for a doctor, who initially said it was probably just a reflex. But then they watched as Sammy's neck turned purple and his pulse started—and doctors rushed him to the pediatric ICU.

“That was a very long night,” remembers Jennifer.

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The next morning, doctors told Craig and Jennifer that Sammy's major organs were shutting down, and he might not survive the day. “That was devastating,” recalls Jennifer, who nonetheless remained hopeful. “After watching my son be pronounced dead and brought back to life, I didn’t believe it… I didn’t think he would die.”

So she went to her son’s bedside and told him exactly that: “I said, 'Sammy, they’re telling us you’re not going to make it through the next 24 hours. I want you to know that I don’t believe a word of it. I have seen you come back to life. And if you can do that, then I truly believe you are going to pull through. I know you will come back to us. I know you will wake up.'”

And later that day, he did. “It was miraculous,” says Jennifer.

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Sammy spent eight weeks at Texas Children’s Hospital, before he was transferred to TIRR Memorial Herman where he underwent another 58 days of rehabilitation.

Doctors discovered that Sammy had suffered a series of small strokes and a serious spinal chord injury. But inexplicably, his parents say, his body sent oxygen to his brain and not his spine. “Thank God, because he’s still Sammy,” says Craig.

Sammy is mostly paralyzed from the waist down, although he does have "some feeling" and "some muscles firing" — just not enough to support his full body weight, according to his dad. But using braces and a walker, Sammy was able to walk out of the rehab facility on his own.

“He is literally a miracle,” says Stacey Hall, D.O., pediatric rehabilitation physician with UTHealth Houston and TIRR Memorial Hermann. “He’s truly amazing.”

Related: Bob Odenkirk Marks 1-Year Anniversary of His Heart Attack with Note of Thanks for Fans' Support

Now a junior in high school, Sammy is back in school full time and taking Advanced Placement classes. Because he has some short-term memory loss, he takes notes in class more than he used to and writes himself reminders. He uses a wheelchair during the school day, but he has therapy five days a week and practices walking daily in hopes of someday being able to walk independently again.

“I want to get as close to how I was before, if I can,” Sammy tells PEOPLE.

His parents are amazed at his positive attitude.

“I don't feel it's worth it to mope and get stuck in all the bad emotions and everything when at the end of the day I'm here, I'm me," says Sammy, who still plays basketball with his friends in his wheelchair. "And I'm still pushing and going. I can still use what I have to do the things I love.”

“No matter what happens, you can still find a way to get through it,” adds Sammy. “Everyone's constantly texting and checking in on me. I feel like all the support has been what's pushed me to get through everything. That’s helped me a lot.”

A GoFundMe has been established to help with Sammy's medical expenses, and Jennifer is also working on a book about her children, and what her kids have taught her.

“No matter how much tragedy you have endured, there are always going to be little miracles that can truly change the world," she says,

“I truly believe that it was [my son] Frankie, on the other side, who pushed Sammy back to us and was, 'It's not your time. You need to go back,'" Jennifer tells PEOPLE. "And I believe it was Frankie who helped him to not only survive it, but to be himself, to have the brain activity and to still have the personality he has."

"I pray every night," she says, "and I talk to Frankie and I tell him, 'Please continue the work you're doing in watching over your brother as he works toward a full recovery.'”

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