Ledecky nearly half a second faster still 4 minutes, 1.73 seconds in her heat by more than two body lengths off the lead before falling in the middle of the way through the eight-lap event was better than the mark set last year.
3:58:37 at the Pan Pacific Championships in August, a few weeks after the fall of last year and 58.86 in the US trials: Ledecky had already swam 3, 400 world records have been set free.
Another record, he was not even a football field where a temporary rally Kazan Arena, on Sunday after the final note.
It will touch the playoffs 4:04:47 Australian Jessica Ashwood, his nearest rival.
France's Camille Muffat won the 400 free Olympic champion Argentina in a helicopter crash in March, was killed in the crash.
Katie Ledecky in the US Women's World Swimming Cham after the 400M free heat ...
Men's 400 Free, and China's Sun Yang, it has been revealed to her doping suspension, the fastest in his first major event.
3:45:37 ahead of Britain's James J. who qualified second, the only difference is in the hands of his collection, winning 44.99: Sun 3 touch.
After watching the sun set and gave the thumbs up to his time.
Australian Mac Horton and David McKeon failed to make the final eight, while 45.86: Canadian Ryan Cochrane 3 was third.
In November, the China Anti-Doping Agency that the suspension of the sun for three months earlier this year after testing positive for doping trimetazidine.
China's Sun Young World Swimming Camp Men's 400M Free heat and gives a thumb up ...
In addition to the Sun, the 2012 London Olympics have won the last two worlds and the 400 free.
Multiple event for its success, "Iron Lady" nicknamed Hungary's champion Katinka Hosszu, Defense, he led 2:07:30 200 individual medley heats. Olympic champion in fifth place in 2:11:23 China's Ye Shiwen.
Hosszu eight days until a meeting of the seven individual events can swim...
Sarah Sjoestrom Sweden 100 butterfly semi-finals qualify for the first time at 56.47. Olympic champion Dana Vollmer of the United States sitting in this tournament, and had only recently returned to competition after the birth of the child...
In non-Olympic events, the Hungarian veteran Laszlo Chih second in 23.32 with French runner Florent Manaudou quick Tayer 50 ,.
China's Sun Yang began to heat swimming world championships men's 400M free ...
"It was a big surprise for me. I think very quickly," Chih that he had a new coach, he added. "I think it is a good decision for me. There are some purpose. And then I started to enjoy it again, please."
Brazil's Cesar Cielo, 50, 14, only barely flyweight champion in the semifinals.
Free men and 400 women, in addition, it is scheduled for the finals of the 4x100 free relays.