Apr 02, 2023

Equine Medical Research Final Report: Working Toward a Genetic Test for Heart Arrhythmias

RESULTS: Researchers record higher than reported incidence of atrial fibrillation in Standardbred racehorses.

Morris Animal Foundation-funded researchers from the University of Minnesota are investigating if genetic variants can help identify horses at high risk of developing potentially fatal cardiac arrhythmias. Cardiac arrhythmias are thought to be an important cause of sudden death in horses during exercise. Most horses that develop arrhythmias have no underlying structural heart disease, making it challenging to detect animals that may succumb to the condition.

Studies in human athletes with arrhythmias, but with no underlying structural heart disease, show the condition is almost exclusively caused by genetic variants. Building on this knowledge, researchers identified 36 variants in a small number of Standardbred racehorses with atrial fibrillation (an irregular heart rhythm). These variants are in genes known to cause arrhythmias in people. The team is testing if these variants are associated with arrhythmias in a larger group of Standardbred racehorses.

Early data showed that 2% of Standardbred racehorses in the study had an arrhythmia (second degree atrioventricular block or intermittent sinoatrial arrest) at rest that is considered normal in fit and healthy horses. About 5% of racehorses also had a history of or were in atrial fibrillation, which is the most common arrhythmia known to negatively affect performance. This is higher than the previously reported frequency of atrial fibrillation (0.14%) in racing Standardbreds.

DNA analysis of samples is ongoing to determine which variants are associated with cardiac arrhythmias including atrial fibrillation. If successful, the team will use this information to develop genetic tests that will become part of screening protocols to help with early identification of horses at increased risk of developing arrhythmias, with the goal of reducing sudden cardiac death in horses. Increased monitoring of horses at high risk of sudden cardiac death will improve our understanding about why certain horses die unexpectedly during and after exercise and may lead to strategies to prevent sudden cardiac death in racehorses.

Thank you, United States Eventing Association, for your generous sponsorship of this study!

Mar 25, 2025 News

In Memoriam: Novelle (2002-2025)

The USEA is saddened to share the passing of Angela Bowles' five-star horse Novelle (Frisk Me Now x Teetawk).

Mar 25, 2025 Volunteers

The VIP Volunteer: Laurie Hogan Finds Peace in Volunteering

Strange as it may seem to some die-hard eventing fans, not everyone seeks out horses in their lives. Sometimes, the horse world chooses the equestrian. And that’s exactly what happened to this month’s VIP Volunteer Laurie Hogan. Hogan has two main passions in life—volunteering at horse trials and jam sessions with a group of local musicians.

Mar 24, 2025 Eventing News

Meet Area VI Teen Harvest Renfro, Who’s Representing the True Spirit of Eventing

Area VI’s Harvest Renfro, 13, and her pony, Take That, or “Robbie,” recently won their first blue ribbon at Introductory at Ram Tap’s February Horse Trials (Fresno, California) on their score of 43.9. Harvest’s accomplishment was even more impressive because she was competing in an open class.

Mar 24, 2025 Eventing News

USEA Podcast #383: The First #TeamTalk with Leslie Law

It's the first Team Talk of 2025 and the first Team Talk with newly appointed U.S. Eventing Chef d’Equipe and High Performance Manager Leslie Law and it is an exciting one! USEA Podcast host Nicole Brown asks Leslie all the big questions: from what his new responsibilities will be, to preparations for the LA Olympics, and more!

Official Corporate Sponsors of the USEA

Official Joint Therapy Treatment of the USEA

Official Feed of the USEA

Official Saddle of the USEA

Official Equine Insurance of the USEA

Official Forage of the USEA

Official Supplement Feeding System of the USEA

Official Competition & Training Apparel of the USEA

Official Horse Boot of the USEA

Official Shock Wave of the USEA

Official Horse Wear of the USEA