Arrhythmias in Equine Athletes

Irregularities in heart rhythm are normal in horses; lub dub, lub dub, pause, lub dub is perfectly natural. There are some irregularities cause concern.

Thumbnail for Arrhythmias in Equine Athletes

By: Teresa Pitman |

Heart-rhythm irregularities, or arrhythmias, are normal in equine athletes, says Ontario Veterinary College professor Dr. Peter Physick-Sheard, who studies heart function in Standardbred racehorses. He explains to Horse Sport the mechanisms behind the heart beating and how normal rhythms vary widely among horses. A steady rhythm is actually abnormal, especially in horses at rest. Irregularities tend to disappear when heart rate rises.

Most arrhythmias originate in the top of the heart (atria) and are usually benign and treatable. Those starting in the bottom of the heart (ventricles) are rarer but generally more serious, often indicating clinical disease that can trigger fainting or death. Treatment usually involves managing the underlying cause.

The article also outlines two Danish studies that concluded both dressage horses and show jumpers frequently experience arrhythmia during exercise and recovery. The research helped establish normal reference values for future cardiac-function studies and provided valuable information for veterinarians.

To read more, go to: