Dehydration is believed to have been the cause for One For Arthur suffering from a fibrillating heart when he was pulled up in the Unibet Grand National Trial at Haydock on Saturday.
The 2017 Aintree hero was given a clean bill of health from Dr John Keen at the Royal (Dick) Veterinary School at Edinburgh on Monday after a scan showed no physical issue with his heart.
The 11-year-old, trained by Lucinda Russell, was fitted with a 24-hour ECG monitor which will be analysed to see if there is any reason the problem might surface again.
“Arthur’s heart is in perfect rhythm and there is no atrial fibrillation any more,” said Russell.
“Dr Keen did a total scan and checked all the valves and the whole structure of the heart and that was found to be very good.
“Everything’s fine so Arthur is wearing an ECG heart-rate monitor that is going to monitor his heart for 24 hours. The technology is absolutely marvellous.
“He’s wearing that and it will be sent back and will be analysed to see if there are any off beats or anything that might cause him to go in to atrial fibrillation again.
“Obviously we want to know the reason for it and to stop it happening again going forward. The conclusion the vets have come to is that it was a dehydration issue.
“The ECG monitor will tell us if there is any other reason for atrial fibrillation, but at the moment the consensus is he was dehydrated and that caused his heart to go into AF. There is no anatomical reason he should do that.
“Until we get the ECG report we won’t know if everything is perfect.”