Frequency and Impact of Cardiac Arrhythmias on Performance in Racehorses

Presentation Description / Summary: The frequency of cardiac arrhythmias in racehorses in surprisingly high given their degree of athleticism. Even horses that are reportedly training and performing at their expected level have a high frequency of arrhythmias. In our population of over 500 horses in race training over 80% have an arrhythmia, including ~29% with complex arrhythmias (including triplets, supraventricular or ventricular tachycardiac or atrial fibrillation). This makes it challenging to interpret clinically, as many of the arrhythmias identified in these horses could be considered clinically relevant if they had been noted in a poorly performing horse. This session will provide an update on the frequency of arrhythmias in racehorses based on previously published work and our large cohort of Thoroughbred racehorses. We will also discuss the types of arrhythmias found and whether the type and/or frequency of arrhythmias are associated with reduced performance in Thoroughbred racehorses.