SANTO DOMINGO - Kiera Aitken cruised into the final of the women's 100 metre backstroke at the Pan Am Games, surprising even herself with her speed through the water.

Aitken, swimming in heat one this morning, finished third in a time of 1:04.98, a new national record and well inside her qualifying time of 1:06.71.

She was fifth overall out of three heats and therefore goes into tonight's finale at the Olympic Stadium in Santo Domingo on a high.

"I'm surprised, I didn't really expect to go that fast," said Aitken afterwards. "It's a personal best by a little over a second and a national record."

Aitken said she felt confident going into a heat in which she was never ranked lower than her finishing position.

"I think I was really mentally prepared and I just tried to get myself up for it," she said. "I felt good because I usually take the first half out kind of slow and this time I tried to get out pretty fast and I think it worked for me."

There was drama in the final heat of Aitken's discipline when Maria Gabrielle Costanza of Paraguay collapsed in the pool at the end of the race and had to be rushed to hospital.

A quick thinking member of the Comision Nacional de Emergencia jumped into the water and, aided by others around the poolside, helped lay her on the ground. Convulsing and in obvious distress she was strapped to a stretcher and rushed to a waiting ambulance in a matter of seconds.

Speaking shortly afterwards a senior member of the Paraguayan delegation said that she had suffered an asthma attack.

Meanwhile, Bermuda's other swimmer at these Games, Ronald Cowen, had a disappointing morning.

Competing in the mens 100m freestyle he clocked 53.07 in heat three for seventh place. He was 27th overall in a time that was well outside his qualifying mark for the event of 52.49.