A baby born with half a heart and given "no chance of survival" is now thriving - despite an hour long cardiac arrest. Rob Velez, 50, and Zofia Fenrych, 41, were heartbroken when doctors diagnosed unborn daughter Dorothea with hypoplastic left heart syndrome (HLHS) at a 16-week scan in February 2022. HLHS is where the left side of the organ is chronically undeveloped. The devastated parents were also told she had a blockage in her heart and without medical intervention would not survive. They immediately set about trying to raise a staggering £2.5 million to cover the cost of a highly specialised procedure. The heart surgery, which was only available in Texas, USA, would have been performed while the baby was still in the womb, with the hopes of increasing her chances to 87 percent. Unfortunately, the parents did not raise the money in time but managed to find a surgeon at Royal Brompton Hospital, London, willing to operate when she was born. Baby Dorothea arrived on June 7 2022 and Rob claims the surgery to reconstruct her heart nearly didn't go ahead because she had "no chance of survival". But thankfully it went ahead when she was seven days old. The procedure went well, however hours after returning from surgery the tot suffered a cardiac arrest lasting over an hour. Medics finally got her heart started again and despite all the odds, Dorothea pulled through and is going from strength to strength. Rob, from Forest Row, Sussex, said: "It was devastating, we did everything we could to give her a fighting chance. "I had a dream we were having a baby girl and bought the pregnancy test for Zofia - we were so excited. "The operation nearly didn't go ahead because we were told she had no chance of survival. "But now we have the most amazing little girl who is thriving - she's our miracle." Zofia and Rob, who already have two-year-old Bathsheba together, were overjoyed to find out they were expecting their second child in October 2021. But the couple’s excitement turned to dismay when a 16-week scan revealed their daughter had HLHS. Zofia, a homeopath, said: "Doctors strongly urged us to terminate the pregnancy because her defect was terrible. "But it was never an option for us - we fell in love with her and couldn't give up on her." The doting pair were determined to see the pregnancy through and began looking into treatment options. They spoke with a specialist foetal cardiologist in the UK who said their baby's heart could be rebuilt when she was three days old. But another blow was dealt when the 24-week scan revealed Dorothea also had a blockage in her heart. The only option was to undergo and in-vitro operation that could increase her chances of survival from five percent to 87 percent. But it came at a cost and would have set them back £2.5million- so April 2022 they got to work fundraising. The parents only managed to raise around £45,000 and at 29 weeks along, they were desperate to find alternative treatment. Then Rob, a former U.S. serviceman, contacted Royal Brompton Hospital - the UK's largest heart and lung specialist medical centre - who agreed to operate on the baby when she arrived. He said: "It was the most complicated case they had ever seen. "But said they would give it a go and we remained hopefully." Zofia went into labour and Dorothea arrived at Westminster and Chelsea Hospital on 7th June 2022 weighing 2lb 7oz. She was whisked off to Royal Brompton Hospital and was due to undergo surgery at seven days old on 13th June 2022. Rob said: "The night before surgery, we were told the doctors were cancelling the op because she wouldn't survive. "The matron said she would have organ failure and be brain dead, but we begged them to go for it. "But we managed to get the hospital to overturn the decision, and we prayed she would pull through." Dorothea spent 11-hours in surgery as doctors "re-wired" the veins and arteries to function from the right side of her heart. To everyone's delight the operation was a success but hours after returning to the ward, she suffered a cardiac arrest. Zofia said: "Doctors came flooding in and trying to bring her back. "They were doing CPR for over an hour. "It was terrifying but somehow she clung on, and they managed to bring her back." Dorothea spent the next six weeks in intensive care with her chest cavity open and hooked-up to a ECMO machine - which works like and artificial heart to pump blood around the body. Despite all the odds stacked against her, she grew strong enough to move to a regular ward and come off the ventilator on 26th August 2022. She will need to undergo another operation on her heart at six months old which they are currently fundraising for but her parents are hopeful for the future. Rob said: "She looks like a healthy baby, and we can't believe how far she's come. "No doctor or nurse can believe their eyes when they see her. "Royal Brompton did what no other hospital dared and we're fore