A heartbroken dad says he 'knew something was wrong' as he put his daughter to bed - and just hours later she was dead.
The sound of Isla's laughter had earlier filled the air as they walked up and down an escalator, which the little girl loved to do.
The six-year-old was exhausted when they got home as dad David Hutton tucked her up in bed, but he knew something was wrong.
Manchester Evening News reports the 38-year-old said: “She climbed into bed but wouldn’t settle down.
“It was just desperation because I knew something wasn’t right.”
Isla was taken to a nearby hospital but died on October 8 last year.
The cause of her death is not yet clear, but it’s believed she may have gone into cardiac arrest or suffered a seizure due to a pre-existing condition.
When Isla was born in 2015, she was diagnosed with long QT syndrome, or LQTS, a heart signalling disorder that can cause fast, chaotic heartbeats (arrhythmias) and affects one in every 2,000 people.
The condition meant Isla’s heart muscle took longer than normal to recharge between beats and she was at constant risk of sudden fainting.
She could also have up to 20 seizures a day and young people with LQTS syndrome have an increased risk of sudden death.
Doctors discovered something was wrong with Isla's heart in the days after her birth.
At just two days old, she was quickly transferred to Alder Hey Hospital in Liverpool and fitted with a pacemaker.
She spent almost one year in hospital until she was finally allowed home just before her first birthday.
Following her discharge, she was treated with a drug called mexiletine, however, the dosage required was so high it often caused seizures.
David friom Ainsworth, Greater Manchester, gave up his job as a primary school teacher to become her full-time carer.
He said: “Life just feels so different.
“It feels like yesterday that she would come and climb on my knee, yet it feels like a lifetime ago. I can see the impact she had on other people and it’s been comforting.
“I was by her side in hospital the whole time. Time seem to flash by but it was like slow motion.
"I wouldn’t have wanted her to be suffering. If she came back around, I wanted her to still be the happy little girl she was. She was the happiest little girl you could have ever met.”
During her life, Isla became the mascot for Thryv Therapeutics, a biopharmaceutical company developing inhibitors to treat various conditions, including long QT syndrome.
The tot helped the company secure more than £12m ($15m) for drug research in the US, with the team using her as the driving force behind their work.
David also went on to co-found charity Team 1C, an organisation which provides a network of support for children with cardiac conditions and their families.
What started out as a way to say thank you to Alder Hey surgeon Dr Ram Dhannapuneni turned into funding four 'Healing Little Hearts' surgery camps in India, through a fundraising ball.
The Team 1C charity is now focused on providing support for cardiac families around the region and creating lasting legacies for children with cardiac conditions.
Projects underway to honour Isla’s life include a cardiac camp in India, funding an EPIC centre with the charity Love The One, a fun day for Team 1C families and a festival in the summer for children and families staying at Alder Hey.
David said: “While bittersweet, it is a huge comfort to me knowing that Isla’s story has inspired a potential cure for Long QT and is helping in the battle against cancer.
“She may go on to save countless lives.”
David has now pledged to raise cash for the hospital that helped treat Isla throughout her life to honour her memory.
So far, he has managed to raise £4,200 for Great Ormond Street Hospital and Children’s Charity by taking part in JanuRun, where donations can be made as David runs 31 miles throughout this month.