UMN researchers study irregular heartbeats in racehorses – The Minnesota Daily

To prevent death in racehorses from irregular heartbeats, researchers are studying horse genetics across Minnesota.

Photo courtesy of Kendall Blanchard

The University’s Akhurst Lab research project aims to identify genetic factors that contribute to the risk of heart problems in racehorses. Photo courtesy of Kendall Blanchard.

Researchers at the University of Minnesota are studying irregular heart rhythms and genetics in racehorses to identify factors that could put these animals at a higher risk of dying from heart problems.
By studying the genetics of horses using blood samples, researchers were able to identify potential genetic variants that put them at a higher risk of death from heart disease. If researchers can identify a genetic component behind these deaths, it will be easier to diagnose these horses before races and help determine breeding decisions, according to the assistant professor and genetics researcher of the Sian Durward-Akhurst University.
This research on racehorses also has the potential to apply to humans and may help explain why some athletes suddenly collapse and die. There are many genetic similarities between equestrian athletes and human athletes, said Durward-Akhurst.
Durward-Akhurst estimated that more than 100 young human athletes collapse and die each year, presumably from irregular heart rhythms.
“People know that [horses] have arrhythmias, but no one has looked at whether or not we can predict which ones have them, ”said Durward-Akhurst. “What I hope is that some of this research will lead to a better understanding of why some human athletes die.”
Some horses have arrhythmias or abnormal heart rhythms, said Dr. Lynn Hovda, chief veterinarian for the Minnesota Racing Commission. Arrhythmias can cause sudden collapse and death in horses during exercise because the heart does not pump enough blood to the brain and around the body.
“If your heart isn’t pumping blood and you just finished the race and you’re not getting oxygen from your blood… then you don’t have oxygen,” Hovda said. “If you don’t have oxygen you will basically die.”
Diagnosing arrhythmias can be difficult because the disease often goes unnoticed until a horse or human dies after exercise. Additionally, healthcare professionals can only diagnose an arrhythmia if a person’s heart is still beating, according to University research assistant Kendall Blanchard.
By implementing genetic testing and more frequent monitoring of horse heartbeats, diagnosing arrhythmias in horses and humans can become easier, the researchers said.
The impact of arrhythmia on horses and owners
When a horse dies of an arrhythmia, it can be a devastating loss for the owner, said Durward-Akhurst.
“Cardiovascular health is essential to the performance of any horse in a discipline such as racing, endurance, show competitions, etc. Said Wendy Wustenberg, owner of Windswept Hill Farm in Farmington, MN.
Wustenberg owns a 20 year old retired show horse named Jay with arrhythmia.
“In the case of my horse, he [were] no clinical signs of illness or impairment in everyday life, but knowing that he has a murmur is good to know, ”said Wustenberg.
According to Wustenberg, diagnosing an arrhythmia in horses is important for trainers and owners, as there may be additional costs and risks associated with continuing to race a horse with arrhythmia.
Atrial fibrillation is a common type of arrhythmia that can lead to death. Every horse that suffers from atrial fibrillation will have a problem if it is forced to exercise, said Durward-Akhurst.
Atrial fibrillation is also very common in humans when an individual has an abnormally large heart.
With atrial fibrillation, “the heart just sits there and shakes,” Hovda said, causing the blood to not be dispersed throughout the rest of the body because the heart is not pumping enough blood.
“If he’s not pumping and he just sits there shaking, you can see that no blood is moving anywhere,” Hovda said.
Durward-Akhurst and his research team are studying the genetics of racehorses with arrhythmias to identify potential genetic causes of these heart problems.
“I was really interested in why some horses have this arrhythmia and others don’t, and there is certainly some evidence to support that there is a genetic component,” said Durward-Akhurst. “If we could understand why some horses die, we can watch for those at higher risk and try to prevent [death]. “
Researchers use a small machine called an electrocardiogram (ECG) to identify horses with heart disease. Researchers have used this equipment to test nearly 500 horses in the States since 2019, said Durward-Akhurst.
By monitoring horses with ECGs when they are both stationary and exercising, and analyzing the results, researchers can determine which horses have arrhythmias, said Durward-Akhurst.
“If we can understand why this is going to happen and on which horses it is going to happen, then we can say, don’t train them on this day because they are at high risk,” said Durward-Akhurst. “It’s really important because no one wants to see a horse collapse and die.”

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