Doctors in the UK are keeping a toddler, born with half a heart, alive using Viagra. Also known as sildenafil, the medication is used for getting and maintaining an erection by improving blood flow in the penis. According to doctors, Hope Stainton has been prescribed this erectile dysfunction medication for three months to keep her blood vessels open following lifesaving surgery.

Hope was born with a condition that meant only the left side of her heart had developed. And so, Hope, who will turn two years old next month, underwent various procedures, including major surgeries along “replumbing” since she was just five weeks old.

According to experts, Viagra keeps the blood flow regulated and boosted to her heart, even as her body has gotten used to the changes. The drug is normally taken in the form of “little blue pills” by men experiencing erection problems.

“People are amazed when I tell them Hope has been on Viagra for three months. I was shocked when the doctors told us - I never imagined something like that would be used for her treatment. But it has worked brilliantly. She’s made an amazing recovery from her surgery, and to look at her now you wouldn’t know she has just half a working heart,” Hope’s mother Kim told The Sun.

Kim said she and her husband Liam were devastated when doctors told them Hope had rare hypoplastic right heart syndrome when Kim was 20 weeks pregnant. “We were anxious when she had the surgery, but she has come through it so well. She has done so well on Viagra – it's really helped her recovery,” Kim added.

Hypoplastic left heart syndrome or HLHS is a rare congenital heart defect that occurs when the left side of a baby's heart doesn't develop properly during pregnancy, resulting in an underdeveloped heart that cannot pump enough blood to the body.

According to the Cleveland Clinic, about one in 3,800 babies are born with hypoplastic left heart syndrome each year in the US. This condition accounts for about 2-3 per cent of all congenital heart diseases. Experts say Hypoplastic left heart syndrome affects more men than women.

Doctors say most of the time, there is no known cause for hypoplastic left heart syndrome, and it is mostly genetic. Babies with mutations or changes in specific genes - GJA1 or NKX2-5 - have a higher risk of HLHS. These genes are known as trisomy 18.

Experts say newborns with HLHS do not always show symptoms immediately and these only develop within a few hours or days of birth. A few of the signs and symptoms include: