SYDNEY • Australian Olympic swimming champion Kyle Chalmers has pulled out of July's world championships in Budapest to have surgery for a worsening heart condition.

The Rio 100m freestyle gold medallist suffers from supraventricular tachycardia (SVT), which occasionally causes his heart to beat faster but is not life threatening.

It forced the teenager to miss Australia's national short-course championships late last year, and his doctor and coach have now decided he needs surgery sooner rather than later to help prolong his career.

Chalmers said: "I have increasingly begun to suffer from an abnormally fast heart rhythm during training and competitions, which now requires surgery.

"The symptoms have reached a point where I must act to ensure I am in peak physical condition for next year's Commonwealth Games trials and hopefully the Commonwealth Games," added the 18-year-old of the Gold Coast event.

"I've suffered from these symptoms during two of the past three major meets, and I have made the tough decision to withdraw (from Budapest)."

His coach Peter Bishop said the swimmer's decision to withdraw was not made lightly.

"We decided it was in Kyle's best long-term interest to get the surgery done," said Bishop.

Australia's coach Jacco Verhaeren said Chalmers' health was of paramount importance.

"Kyle has our full support and we know he will use this time away positively and to his advantage to return for a home Commonwealth Games in 2018," he said.

Chalmers is due to have surgery in the coming weeks.

AGENCE FRANCE-PRESSE, THE GUARDIAN