Married Jac, 54, got £15,000 for her two-year-old Nissan Qashqai so little Louie could have a mitral valve repair.
Prof Daniel Brockman led surgeons in a four-hour op using general anaesthetic at London’s Royal Veterinary College.
Louie’s heart was stopped for 90 minutes as a machine pumped blood around his body.
He spent two days in intensive care, was kept in for a week to recover and is now doing well at home three months on.
Jac, of Wareham, Dorset, said: ‘Although it was an awful lot of money, I thought I owed it to him. He’s such a sweet little dog, I love him to bits.
‘He’s only 10 years old and chihuahuas can live to 16 or 17.’
Louie’s condition was spotted by a cardiologist before a routine teeth-cleaning procedure two years ago.
Jac said: ‘I asked about our options and the vet mentioned there was surgery but it was new, very expensive and very specialised.
‘It’s only done in three places in the world – London, Cambridge and Japan.
‘The surgeon said we had nothing to lose but a lot of money because he’d die without it – probably by the end of the year.’
The retired RSPCA nurse added: ‘We didn’t have insurance – if they can wiggle out of paying out, they will.
‘So we took the risk and said if vet bills arise we’ll cross that bridge when we get to it.
‘I know it’s a lot of money but at the end of the day, if you love your dog that much, at least there’s an option.’
