Clydesdale benefits from cardio technique developed at OVC
BY BARRY GUNN, OVC
A one-of-a-kind horse has a new lease on life thanks to a technique pioneered at the Ontario Veterinary College. The nine-year-old Clydesdale was successfully treated for atrial fibrillation (irregular heart rhythm) by using catheter-mounted intracardiac electrodes to deliver a high-voltage jolt to the heart. The patient, an 885-kilogram colossus named Phantom, is the largest ever treated using the technique, says OVC veterinarian Kim McGurrin.
“With a large, heavy horse, there is always an anesthetic risk, so we had to work as quickly and efficiently as possible,” says McGurrin. “And then it's just uncharted territory with the cardioversion. The largest horse we've ever done prior to this was 730 kilos.”
Atrial fibrillation is traditionally treated with the drug quinidine, which can have adverse side effects, she says. Plus, some horses, especially larger breeds, don't respond well to the drug.
“This horse was in atrial fib for at least six months to a year. And historically, it was thought that if a horse was fibrillating for more than four months, it had an extremely poor chance of responding.”
Phantom's owner, Stanley White Jr. of Argyle, Tex., searched for treatment alternatives for nearly a year. Finally, his veterinarian heard about the technique developed at OVC by a team that includes McGurrin, Prof. Peter Physick-Sheard, Clinical Studies, and veterinarian Dan Kenney. Within days of contacting OVC, White loaded Phantom into a trailer and drove 2,500 kilometres to Guelph. Phantom underwent the procedure Oct. 6 and was on his way back home two days later.
“I'm just ecstatic with the results,” says White. “He is one of a kind. (Clydesdales) just don't come that big in black.”
Phantom stands more than 19 hands high (about six feet six inches at the shoulder), so big that White has been unable to find a perfect hitch mate for the gentle giant. White believes the heart problem emerged after Phantom overexerted himself during a competition.
“It couldn't have worked out any better,” he says. “I just wish we'd found y'all a year ago.”
OVC was the first in the world to successfully adapt to horses a treatment that is commonly used for atrial fibrillation in humans. It involves threading two catheters from the horse's neck through the veins into the heart and positioning the electrodes in the right atrium and pulmonary artery. The catheters are fitted with electrodes that deliver a shock to correct heart rhythm.
Recovery time is much quicker than with conventional methods. Horses can be doing light work within two days and can resume regular training in a week.
The OVC team's work was featured at the 2005 American College of Veterinary Internal Medicine forum in Baltimore, and McGurrin will be presenting at the American Association of Equine Practitioners convention in Seattle in December.
