Editor’s note: This article is part of TheHorse.com’s ongoing coverage of topics presented at the 2012 American College of Veterinary Internal Medicine Forum, held May 30 – June 2 in New Orleans, La.

Many equestrians agree that it takes a horse with a special heart, mind, and athletic ability to reach the upper echelons of their sport. But now scientists have confirmed at least one part of this theory: Recent study results indicate upper level endurance horses have some different cardiac specifications than their lower level counterparts.

Mary M. Durando, DVM, PhD, Dipl. ACVIM, of Equine Sports Medicine Consultants, in Newark, Del., discussed the results of a study that compared elite and non-elite endurance horses’ echocardiographic measurements at the 2012 American College of Veterinary Internal Medicine Forum, held May 30 – June 2 in New Orleans, La.

"In Thoroughbred racehorses an association has been made between caliber of racehorse, maximal oxygen consumption, and certain echocardiographic variables in longer, more aerobic races," Durando explained. "The purpose of this study was to determine if performance ability is related to echocardiographic indices of cardiac dimensions or function in endurance Arabians, because the sport has such a large demand on aerobic function."

Durando and colleagues evaluated 22 elite endurance horses and 18 non-elite horses, all Arabians between the ages of 7 and 17 years; horses were classified as elite or non-elite based upon recent finishes in specific American Endurance Ride Conference 100-mile rides.

Key findings, Durando relayed, inc