The 27-year-old short track skater, who won a bronze medal at the 2018 Olympics, was admitted to hospital in Perpignan, France last month after falling ill during a training camp.
She was placed in intensive care and kept in an artificial coma but despite undergoing surgery, her health continued to deteriorate.
"What horrible news we've just received. Her loss will be felt through the whole sporting world," said Dutch short track coach Jeroen Otter.
"It is an enormous blow for a close-knit group. We've missed her over the last two weeks but today's news is so definite and surreal."
Van Ruijven won the 500 metres title at the world championships in Sofia last year, and an Olympic bronze medal in the 3,000m relay at 2018 Pyeongchang Games.
"We feel the pain for her family and the short track team," said KNSB director Herman de Haan. "This is hard to comprehend. On behalf of KNSB I want to wish Lara's friends and family strength with dealing with this great loss."