Heart condition forces Belgian cyclist Van Hooydonck to retire aged 27
"After a series of tests we've diagnosed a heart irregularity," Jumbo-Visma reported.
"It provoked the problem that almost cost him his life last week.
"This discovery means the end of his professional career," the team's statement added.
Van Hooydonck raced the Tour de France in July, helping his teammate Jonas Vingegaard win the overall title.
But last week he was lucky to escape with his life when, feeling unwell at the wheel, he caused a multi-car accident at a crossroads in Kalmthout in northern Belgium.
Van Hooydonck's pregnant wife Alicia was also in the vehicle but was unhurt.
He was rushed to hospital in a critical condition and was fitted with a heart defibrillator.
"I realise that I was incredibly lucky," said Van Hooydonck, who left hospital in Antwerp on Wednesday.
"I'm doing well but I have to accept the idea that it's the end of my career.
"I'm going to concentrate on my recovery and becoming a father.
"Everything is fine with Alicia and the pregnancy and we can't wait for the birth. That is really helping me."
