A woman shot in the heart during the Las Vegas massacre miraculously survived thanks to the quick-thinking actions of her firefighter boyfriend who rushed her to hospital.

Christina Kitcat was at the open-air Route 91 Harvest country music festival with her boyfriend Kelly Culbertson, who had got them tickets as her birthday present.

The couple initially thought the gunfire was fireworks, but Culbertson soon realised they were caught up in a mass shooting as gunman Stephen Paddock opened fire on music fans from inside room 32135 at the Mandalay Bay Hotel.

“I’m like why did everyone bring fireworks? Why did everybody disperse? Then another round of fireworks goes off, and she looks at me and says, ‘It’s hard for me to breathe,’” he told the Daily Beast.

The 27-year-old used all his trauma experience as a firefighter and Emergency Medical Technician to get quickly assess his girlfriend’s injuries and get her to safety.