Researchers confirmed that atrial fibrillation is detrimental to athletic performance by studying retired Standardbred racehorses working on a treadmill. | Photo: Courtesy Dr. Rikke Buhl

Up to 4% of Standardbred racehorses suffer from cardiac arrhythmias known as atrial fibrillation. That’s eight times more than the general horse population. While results from a recent study confirmed that it’s hereditary in the breed, researchers looked at the extent to which atrial fibrillation affects heart function and performance. And the findings, they say, are concerning.

“I was extremely surprised, and actually also quite scared, about the very high heart rate and abnormal cardiac beats observed on the electrocardiogram (ECG),” said Rikke Buhl, DVM, PhD, a professor (mso) at the University of Copenhagen’s Department of Veterinary Clinical Sciences, in Taastrup, Denmark.

“Previously I hadn’t been too worried about people riding or driving horses suffering from atrial fibrillation, but after this study I am more concerned,” she said