Denman's heart is not an issue, vets insist
• Gold Cup winner's heart condition more serious in human
• Experts agree that problem is unlikely to recur
Never mind all the "will-he-won't-he?" surrounding Tony McCoy and his pursuit of 3,000 winners. The question that will preoccupy true punters this week concerns Denman, the Gold Cup winner, and his delayed reappearance at Newbury on Saturday.
Should we recall the way Denman dismantled Kauto Star at Cheltenham in March and back him for the Gold Cup now, before the price vanishes? Or oppose him, at Newbury and at the Festival, on account of the heart problems that have kept him away for months? After all, you would not back a human athlete to win an Olympic gold on the track if you knew he had a dodgy ticker, would you?
This makes Dr Celia Marr's opinion on the subject particularly interesting. Marr is neither a trainer nor a heavy-hitting gambler, but the senior vet who directed Denman's treatment at Rossdale's equine hospital in Newmarket, and she offers a fascinating insight into Denman's "heart op" last year. There wasn't one.
"There was no operation at all, because there wasn't any need," Marr said. "The idea seemed to take hold that it was like an episode of Casualty, that we stopped his heart and then went off for a cup of coffee before starting it again. His condition was one that can require an operation if it does not respond to treatment with drugs, but in his case, he did respond, so there was no need to operate.
"The condition that he had was atrial fibrillation, which is quite common in racehorses, and also quite common in middle-aged men, too, so people may well have heard of it in relation to Tony Blair and Sir Alex Ferguson.
"But it is more serious in humans. In horses, obviously it means that the horse can't perform appropriately, but if it is picked up early, as it was in this case, it often responds very fully to treatment. It's very much either there or it isn't and when it's gone, it's gone."
Rather than being a sign of inherent frailty, the problem suffered by Denman may in fact be an indicator of his talent as a racehorse.
A number of great Flat racehorses, most famously Eclipse, Phar Lap and Secretariat, had abnormally large hearts - at 22lb, Secretariat's was more than twice the average size. A large heart can, however, also make a horse more prone to conditions such as atrial fibrillation, according to Dr Lesley Young, one of the country's foremost experts on equine cardiology.
"The better the horse, especially in National Hunt racing, the bigger its heart is likely to be," Young says.
"Basically, what's happened over the last two millennia is that we've bred a cardiovascular monster. Breeding for speed and endurance in the thoroughbred has bred a heart and cardiovascular system that is almost too big for itself. Big horses are an atrial-fibrillation accident waiting to happen.
"Denman's not the first National Hunt horse to suffer a problem like this and he certainly won't be the last, but the vast majority will suffer it once and then never again.
"You can't say that that is absolutely the case, but the longer a horse has been normal since it happened, and in his case it's been three or four months now, then the greater the percentage chance that the heart will stay normal."
The agreement among the experts that Denman's heart condition is unlikely to recur could be all that some punters need to step in and back him for the Gold Cup at his current top price of 7-4. He was, after all, significantly shorter at the start of the season and has been matched at just over evens on Betfair.
But it also gives us all a chance to pause for a moment and consider the extraordinary power lurking in every thoroughbred's frame.
"The bottom line is that any big horse can have an abnormality in its heart rhythm at any time," Young says. "There's a percentage chance that any horse in a race on any given day will have an atrial fibrillation, never mind Denman.
"With the set-up at Paul Nicholls' yard, where they work up a steep hill, it was quickly obvious that something wasn't quite right, but if a horse is trained in Newmarket you can find that its heart will just beat a little faster to make up for the fact that it's not as efficient as it should be.
"Then it's only in a race that it will become apparent that the horse is like a car that's firing on only two cylinders.
"What they're losing is their turbo-charge. A young horse can have a peak heart-rate of 240 beats a minute, and while it's age-related and National Hunt horses would be a bit less, it is still huge compared to us and a huge range, too, when you think that it will start out at about 26 beats per minute."
It has been nearly 11 months since Denman won the Gold Cup and some National Hunt fans have started to doubt whether he will return with his talent undiminished. Yet his big heart, at least, seems likely to be doing precisely what it should.