In horses, humans and all other mammals, the heart is responsible for delivering oxygenated and nutrient-rich blood throughout the body and removing metabolic waste through a vast network of blood vessels, therefore any disruption in this process can have detrimental effects. In horse racing, and most other equestrian sports, the term "heart attack" has become a catch-all phrase for suspected fatal cardiac events, as was the case recently with the passing of G1 Dubai Golden Shaheen winner XY Jet (Kantharos), who died of an apparent cardiac event the morning of...