The sudden death of Olympic show jumping champion mount Hickstead Nov. 6 could have been caused by a number of factors and not necessarily cardiac arrest, according to the the Fédération Equestre Internationale’s (FEI) top veterinary official .

"Until the results are known, it cannot be assumed that (the cause of death) was (a cardiac event)," Graeme Cooke, MA, VetMB, MRCVS, FEI veterinary director told The Horse. "Just like in everyday human life, there are several–but fortunately all rare–possible causes of a sudden collapse such as this."

Ridden by the current No. 1 international show jumper, Eric Lamaze from Canada, the 15-year-old bay KWPN stallion collapsed in the Rolex FEI World Cup show arena in Verona, Italy, Sunday. The horse and rider team had just completed the Rolf-Ludi-designed 13-fence course with only four faults, the FEI reported. Videos on YouTube, some with more than 200,000 views over the past two days, show Hickstead calmly walking out of the arena before suddenly weakening, sitting back on his haunches, and falling as Lamaze dismounts.

"It’s very sad news indeed, and a very unusual event for an FEI discipline such as jumping," Cooke said. Although the discipline does not require "in-depth pre-competition tests" to study the horse’s health status (for example, as would be used in an endurance race), Cooke said horses at this level are nonetheless very well-monitored and that there is no reason to believe there were any pre-existing conditions responsible for the stallion’s death