It's on with the show for Kiwi mare Lizzie L'Amour tomorrow night.

And don't be surprised to see her run a huge race in the A$200,000 Stocks Stakes at Moonee Valley - despite the fact she made an inglorious Australian racing debut at the same track three weeks ago.

Prepared by Murray Baker and Andrew Forsman, Lizzie L'Amour was beaten 27.8 lengths in the group two Dato' Tan Chin Nam Stakes.

The group one-winning mare suffered a bout of atrial fibrillation and while it sounds terrifying, horses generally take little time recovering.


That doesn't help the poor punter, of course, but it gives renewed hope to connections after they are left scratching their heads following a horrendous performance by their horse.

Atrial fibrillation is, in layman's terms, an abnormal heartbeat. The normal rhythm is suddenly thrown out and the heart can't pump blood around the body as efficiently as it should.

Racing Victoria's veterinary services manager Grace Forbes told not enough is known about atrial fibrillation and it is the topic of a three-year research project due to be started this season.

"What we do know is that 90 per cent of horses that suffer [an attack] will fully recover without intervention within 24-48 hours and once back in rhythm there'll be no lasting problem," said Forbes.

"A very small portion may suffer another attack in the future. Five per cent of horses that have an episode might have another within two years." Forbes said the occurrence of atrial fibrillation had not increased in recent times, despite the fact it was "showing up" more in stewards' reports.

"The fact is that testing for poor performance has more than doubled in the past five years," she explained.

Sadly for those investing, there is no atrial fibrillation warning sign before a race, but Forbes said once a horse had suffered an episode, there were monitoring procedures.

"Once a horse is diagnosed with it, the stable vet must do an ECG [electrocardiogram] test to demonstrate all is okay. And before racing again the horse must work over 1000 metres in front of a steward and a vet will then listen to the heart for normal rhythm," she said.

Meanwhile, Golden Slipper Stakes winner She Will Reign was afforded few favours in her first run as a three-year-old after drawing awkwardly in barrier 11 for tomorrow night's Group 1 Moir Stakes.

She Will Reign, who was expected to arrive in Melbourne in the early hours of today, will start from gate 10 of 13 runners if the four emergencies - Hellbent, Supido, Super Cash and Ability - fail to make the final line-up.

There were 18 final acceptors for the $500,000 1000-metre scamper, with the mare Ocean Embers failing to beat the ballot.

There will be no shortage of pace in tomorrow night's race as drawn out with She Will Reign is the early race favourite Russian Revolution (barrier 14) and the flying Flemington mare Heatherly (13).

As expected, the Magic Millions winner Houtzen dropped out of Moir contention to concentrate on getting back to winning form when she takes on fellow fillies in the set-weights Scarborough Stakes over 1200m.

Hong Kong superstar Joao Moreira is set to ride at The Valley tomorrow night where he is hoping to add a Moir Stakes victory to the group one Oakleigh Plate he won last season aboard the speed mare Sheidel.