Cardiac Symptoms in Horses By Katie Navarra | September 24, 2012 | 1 minute read Symptoms of heart problems include an inability to perform work at a level previously achieved successfully or if the horse shows an unusual tendency to tire. A discussion by Equine Guelph researcher, Dr. Peter Physick-Sheard. CLICK HERE TO VIEW THIS VIDEO. What did you think of this article? Submit Rating Thank you for your feedback!