Trainer Nicky Henderson has not ruled out running Sprinter Sacre again this season after the superstar's heart problem righted itself.
The seven-year-old was found to be suffering from an irregular heartbeat after he was pulled up by Barry Geraghty on his seasonal return in Friday's Desert Orchid Chase at Kempton.
Sprinter Sacre returned to Henderson's Seven Barrows base on Friday night but was sent to Newmarket for assessment by Celia Marr, a specialist in equine internal medicine and cardiology, on Saturday.
Marr confirmed the original diagnosis of atrial fibrillation and decided to give the horse time to see if his heartbeat regulated itself.
Henderson told Press Association Sport: "The good thing is that the fact it has self-righted means we don't have to go into the process of using any drugs.
"Quinidine is the normal solution for this kind of problem, but it's a risky drug and it's good news we don't have to go down that route.
"Celia wants to come down to Seven Barrows on Friday and canter him using an ECG, so we will see how that goes.
"The important thing is that it is only a very recent onset (of the problem). Barry was so quick in picking up something was wrong and in pulling him up at Kempton.
"It would be speculation (to say he won't run again this season).
"We're talking about cantering him again on Friday, so you wouldn't rule out training him again this season.
"It's got to be a step at a time with him and we will know more in the coming weeks as he is back in light exercise, and we will continue to monitor him."