Doctors stopped eight-year-old Ali\'s heart Thursday afternoon to correct a congenital defect, while his anxious father sat outside in the waiting lounge in the Dubai Hospital. The boy\'s father, Parvez, said the hospital called and told him to bring his child to them. The delicate operation, lasting hours and requiring a team of top surgeons from Italy, was free for the Pakistani expatriate. Life-threatening About 30 children and one adult with life-threatening heart deformities will be operated on during a two-week visit by surgeons from San Donato Hospital in Milan. Article continues below Dr Obaid Al Jasem, Director of the Heart Centre at Dubai Hospital, said parents with children having heart problems can call the hospital for a free consultation and treatment during the surgeons\' visit. This is an initiative of the Mohammad Bin Rashid Al Maktoum Charity and Humanitarian Establishment in collaboration with the Dubai Health Authority (DHA), he said. Map of arteries Ali earlier underwent a cardiac catheterisation procedure where a tube was inserted through his thigh to map out the heart arteries and veins. This is essential because once the boy\'s heart was stopped and blood drained out of his body, surgeons can still follow the pathway of the blood vessels using this ‘map\'. Clinical perfusionist Suresh Robert said two litres of blood was drained out from the boy\'s body into a heart-lung machine. Machine circulates the blood The machine adds oxygen and removes carbon-dioxide and circulates the blood into the rest of the body . Without the oxygenated blood, Ali\'s brain would have died within three minutes. The heart, which keeps pumping rapidly, has to be stopped to allow the doctors to do the operation and the blood taken out so that it stops flowing around the heart. \"Now, the towel, please,\" said Dr Allesandro Giamberti, the head surgeon. Scrub Nurse Shiny Thomas, handed him a small towel which was inserted in a cavity under the heart. Meanwhile, circulating nurse Meena Shaji was keeping track of what is being used for the operation, writing it on a white board on the wall.