Sprinter Sacre was sensationally pulled up on his comeback in the williamhill.com Desert Orchid Chase at Kempton won by Sire De Grugy.
Trainer Nicky Henderson had been forced to skip the Tingle Creek with the highest-rated jumps horse in training due to an unsatisfactory scope and this Grade Two was suddenly the focus of his attentions.
Slightly awkward at a couple of his early fences, Barry Geraghty pulled him up with just under a mile to run but remained on board as he trotted back.
Sire De Grugy, who won the Tingle Creek, was not that hard pressed to beat Oiseau De Nuit by four lengths.
The eventual winner was sent off at 4-1 to reward Gary Moore for his decision to take on Sprinter Sacre.
Henderson said: "They (vets) listened to him when he pulled him up and when he came back in, and there is an irregular heartbeat there.
"He landed on the back of the fence and Barry said he was empty.
"He was looking great, he jumped the first very well and his work was unbelievable
"He is going to have to go for dope tests and then they will scope him and hopefully we will know more later."