The toddler, now three, and his grateful family yesterday met with the doctors and paramedics who saved his life after his heart stopped beating.
Determined not to let the youngster slip away, Dr Rich Lyon continued to work on his tiny heart, when he was struck down with an illness previously unheard of in children.
His mother Kelly Clark, 32, yesterday said: 'We are just so grateful that he is still with us.
'He was pronounced dead for six minutes so it is a miracle that they could bring him back.
'He suffers from a rare condition called Hypertrophic Cardiomyopathy which we think is what triggered the heart attack.
'We love him so much and I just don't know what I would have done if he died.
'What the doctors and paramedics did was truly amazing I can't thank them enough if it was not for them my son would not be here.'
Kai's disorder causes the heart muscles to become unusually thick.
It triggered him to develop the condition Ventricular Fibrillation at his home in Clacton-on-Sea, Essex on October 17 2011.
The disorder, which causes the heart to beat in a severely abnormal rhythm, is rare in adults and almost unheard of in children.
The muscles in the lower chamber of the heart begin to randomly twitch which causes blood to stay in the heart when it should be pumped around the body.
Following the attack his distraught parents rang 999 and the East of England ambulance service were called to the scene.
A team of paramedics rushed to the youngster's side and managed to resuscitate him.
The East Anglian Air Ambulance Service were then called and put Kai into an induced coma, before flying him to Addenbrooke's Hospital, Cambs.
He was later transferred to Great Ormond Street Hospital, London.
The youngster was kept in hospital for five weeks and treated by specialist medical staff.
Doctor Rich Lyon who treated Kai on his way to hospital said: 'It is very rare for such a young child to have a heart attack.
'I have never ever heard of such a young child suffering from Ventricular Fibrillation it is incredibly rare.
'In fact Kai has become somewhat of a medical mystery. It's fantastic to see Kai doing so well.'
During the emotional reunion at Cambridge Airport Kai along with his father Phillip, 42, and siblings Josh and Kaitlin met members of the East Anglian Air Ambulance Service.
While he was there the youngster was given the tour of the helicopter that saved his life and was allowed to play in the cockpit.
