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Clydesdale's Big Heart Skips More Than a Beat

By: Louisa Shepard Date: Feb 10, 2015

Windsor, leading a team of ClydesdalesLeading the team of majestic Clydesdales is Windsor, a special member of the eight-horse team that pulls a historic wagon for the Hallamore Corporation. So when he wasn’t himself, not pulling his weight, backing out of the harness, farm manager Ned Niemiec worried about Windsor’s heart.

Two other horses in the team had shown these signs in recent years, he said, and the diagnosis was atrial fibrillation causing an irregular heart rhythm. So when their primary vet suspected the same condition, Niemiec loaded up Windsor for the seven-hour drive from Lakeville, Massachusetts, to New Bolton Center.

“We’ve enjoyed a strong relationship with New Bolton for many years,” said Niemiec, who manages all aspects of the Hallamore Clydesdales. “We believe in the top, top reputation, especially in the cardiac area.”

Dr. Virginia Reef, Director of Large Animal Cardiology and Diagnostic Ultrasonography at New Bolton Center, is an expert in equine atrial fibrillation, known as a-fib for short.

“When a horse has a big heart, atrial fibrillation is more likely,” said Reef, who is also Chief of the Section of Sports Medicine and Imaging.

A Horse with Heart

Windsor, foaled in England, is a 12-year-old gelding that weighs more than 2,200 pounds and stands more than 18 hands high. “He’s huge,” Reef said.

Distinctive, with a large white blaze on his face, Windsor is one of 17 Clydesdales that live on the 40-acre farm of Dennis Barry, who for nearly 45 years has indulged his passion for the breed with his eight-horse hitch.

BWindsor, leading a team of Clydesdales in a paradearry owns Hallamore, a heavy-hauling transportation and equipment company that started in 1895 hauling loads with horses. To promote the company and foster positive public relations, a team of eight Clydesdales pulls an orange wagon, built in 1899, in parades and at local fairs. 

“Windsor is one of the stars of our operation here,” Niemiec said. “He’s a wonderful horse. He’s one of the favorites in the barn. He’s not only handsome, he works well, too, and he has a great personality. Willing and attentive, alert and easy, he wants to do his job.”

There was no question that the Hallamore team would do everything they could to get Windsor the care he needed.

Cardiac Care at New Bolton Center

The electrocardiogram (EKG) confirmed the diagnosis of atrial fibrillation, Reef said. Windsor’s heartbeat was more than 80 beats per minute and didn’t settle down, compared with a usual rate of 50 beats per minute. Reef treated him with sotalol, an anti-arrhythmic drug with beta-blocking properties. “We wanted to slow the heart rate,” she said.

Windsor entering the Scott Equine Sports Medicine Facility for imagingReef and her team, including Dr. Fe ter Woort, a Fellow in Equine Cardiology and Ultrasound, also performed an echocardiogram (an ultrasound exam of the heart) and confirmed that Windsor did not have obvious structural heart disease, such as a leaking heart valve.

One of the ways to “convert” atrial fibrillation is to give the horse intravenous doses of quinidine gluconate, Reef said. This drug can be successful if the atrial fibrillation is new, and the horse does not have structural heart disease, like Windsor.

“We gave him small doses for a good part of the day, and the a-fib resolved,” Reef said.

The treatment worked, but the veterinarians had to watch for “premature" heartbeats, extra beats just before the regular beats. Windsor was on a continuous electrocardiogram around the clock.

Windsor awaiting an ultrasound“He did have a few atrial premature heartbeats," Reef said. "And when he was on the trailer getting ready to go home we heard a number of them.” 

Windsor was sent home on the drug sotalol to try to suppress the atrial premature heartbeats. Reef also gave him benazepril, a drug that has been proven to help prevent re-occurrence of atrial fibrillation in humans.

In addition, she recommended potassium chloride supplements because the level of potassium excreted by Windsor’s kidneys was low. A potassium deficiency can cause the premature beats, and those premature beats can trigger atrial fibrillation, Reef said. “If the body is depleted of potassium, this can make it more likely for a-fib to occur,” she said.

Heading Home With a Heart Monitor

Windsor in the stocks awaiting imagingNiemiec went home with a 24-hour EKG to monitor Windsor’s heart. He did the recordings two weeks later, both standing in the stall, and while exercising, and sent the results to Reef.

Ultimately, they weaned him off the drugs and his heart rhythm stayed steady.

“He’s right as rain,” Niemiec said. “He seems to tolerate the work, whatever we ask him to do.” 

Windsor’s heart has made it past the critical four-month period, which is when most relapses occur, Reef said.

“He’s past the first marker, which is good,” Reef said. “But he could still experience a recurrence. So they need to make sure his electrolyte status is good, and make sure he gets potassium supplementation, especially if he works very hard.”

Lately Windsor has been working very hard, running around in several feet of snow. “The horses love it. They get daily turnout in the snow,” Niemiec said, describing the aftermath of the recent New England blizzard. “They are stabled and turned out a portion of every 24 hours. We believe a horse needs to be a horse.”

A team of Hallimore Clydesdales pulling the Studebaker wagon built in 1899.

About Penn Vet

Ranked among the top ten veterinary schools worldwide, the University of Pennsylvania School of Veterinary Medicine (Penn Vet) is a global leader in veterinary education, research, and clinical care. Founded in 1884, Penn Vet is the first veterinary school developed in association with a medical school. The school is a proud member of the One Health initiative, linking human, animal, and environmental health.

Penn Vet serves a diverse population of animals at its two campuses, which include extensive diagnostic and research laboratories. Ryan Hospital in Philadelphia provides care for dogs, cats, and other domestic/companion animals, handling more than 34,600 patient visits a year. New Bolton Center, Penn Vet’s large-animal hospital on nearly 700 acres in rural Kennett Square, PA, cares for horses and livestock/farm animals. The hospital handles more than 6,200 patient visits a year, while our Field Services have gone out on more than 5,500 farm service calls, treating some 18,700 patients at local farms. In addition, New Bolton Center’s campus includes a swine center, working dairy, and poultry unit that provide valuable research for the agriculture industry.