Olympic bronze medalist Miners Frolic, ridden by Great Britain’s Tina Cook, has been retired due to a non-life-threatening cardiac condition, his treating veterinarian said.

The 16-year-old dark bay Thoroughbred gelding was found to have atrial fibrillation, said Celia M. Marr, BVMS, MVM, PhD, DEIM, Dipl. ECEIM, MRCVS, of the Rossdales Equine Hospital and Diagnostic Centre in Newmarket, England.

“Atrial fibrillation is performance-limiting, but it is certainly not life-threatening,” Marr said. Miners Frolic had a safe journey to his retirement home following the Feb. 4 decision, she added.

One of the more common forms of equine heart disease, atrial fibrillation occurs when the heart beats out of rhythm due to a malfunction in the atria, Marr explained. The atria are the two chambers (out of four total) which receive blood coming in from the circulatory system. Veterinarians talk about “electricity” in the heart because there are actual electrical pulses which control the beat. If part of the heart gets off beat, the heart cannot function properly, and this is considered an electrical problem known as arrhythmia. Atrial fibrillation is a type of arrhythmia in which the atria fibrillate (or quiver) instead of contract, putting the heart off-beat.

An example of atrial fibrillation, as seen on an electrocardiogram. Each large spike represents a heart beat, and it’s apparent that these are occurring at irregular intervals. Between beats, there is continuous