Three-year-old Aaron Sweeneyâ€™s heart can stop for up to seven minutes each time he suffers a collapse.
He is only alive thanks to his mother Jolaine Clark, 28, who has been trained to revive her son using a hand-held defibrillator which she keeps with her 24 hours a day.
Since his first collapse, which happened while he was watching television just over a year ago, Aaron has suffered five heart failures, three in the last three months.
But despite his constant brushes with death the cheeky lad, who has been diagnosed with Prolonged QT Syndrome, known as â€˜Sudden Death Syndromeâ€™, still enjoys running around his home in Mosspark, Glasgow.
Jolaine said: ‘Heâ€™s just a normal three-year-old. The doctors said heâ€™s not supposed to run around but I canâ€™t stop him.
‘He always racing around the flat and riding on his little electric quad bike.’
Aaron, who lives with his mother and grandparents Elaine, 50, and Joe, 50, first collapsed while watching TV at his home in January last year.
Quick-thinking paramedics managed to revive the boy and he made a full recovery.
But doctors at the cityâ€™s Yorkhill Hospital failed to diagnose the condition.
Aaronâ€™s family were all trained to use a special hand-held defibrillator so he could return home and continue to attend nearby Martha House Day Nursery.
In March last year he collapsed again and had to be revived.
It was only when brave Aaronâ€™s heart failed for a third time in December that doctors finally diagnosed him with Sudden Death Syndrome, a heart defect which develops in the womb.
Jolaine, a former debt collector, added: ‘As a mother itâ€™s terrible to have to watch your son collapse and have to revive him.
‘The first time it happened I didnâ€™t know what to do. It was horrendous.
‘At least now I am trained to help him, but I canâ€™t go back to work and heâ€™s off school at the moment.’
Aaron was fitted with a special cardiac monitoring device, which was implanted in his chest in January.
The device detects the moment when Aaronâ€™s heart begins to fail and starts to record the condition of his heartbeat for doctors to read when he is taken to hospital.
The young boy, whose heart failed as recently as last month, will undergo an operation later this year to fit a small permanent defibrillator under his skin that will trigger automatically if his heart begins to fail again.
Jolaine added: ‘Heâ€™s really great, always happy. He knows something is wrong with him but he handles it really well.
‘We go for check-ups at Yorkhill every six to eight weeks and we are holding various charity events to try and raise money to keep a defibrillator at his school when he is old enough to go.‘