American swimmer Anita Alvarez rescued by her coach in dramatic scenes at World Aquatics Championships

American artistic swimmer Anita Alvarez had to be rescued from the pool by her coach at the World Aquatics Championships after losing consciousness following her solo free final routine in Budapest.

Andrea Fuentes, a four-time Olympic medallist in synchronised swimming for Spain, sprung in to action after she saw Alvarez sink to the bottom of the pool.

The 25-year-old received medical attention before being taken away on a stretcher.

It was the second time Fuentes has had to rescue Alvarez after she leapt into the pool during an Olympic qualification event last year and pulled her to safety along with the American's swim partner Lindi Schroeder.

"Anita is much better, she is already at her best. It was a good scare, to be honest," Fuentes told Spanish newspaper Marca.

"I jumped into the water again because I saw that no one, no lifeguard, was jumping in. I got a little scared because she wasn't breathing, but now she's fine. She has to rest."

No decision has been made on Alvarez's participation in Friday's team event.