It is important to assess the impact of heart murmurs on both athletic performance and the safety of the rider and animal, a specialist told the Australian Veterinary Association annual conference in Perth this week.
Dr Guy Lester, from Murdoch University in Perth, told delegates that cardiac murmurs were heard in horses across a wide range of ages.
“There’s a range of techniques that can be used to assess cardiovascular function in horses including echocardiography, field exercise testing and lab tests.
“Exercise testing is important to determine if the murmur is associated with cardiac arrhythmia during exercise and if it’s appropriate for the level of work the horse is performing.
“Equine heart disease can be difficult to definitively diagnose, but the attending vet should have a high index of suspicion based on auscultation. It’s important to use a good stethoscope, that’s properly maintained and positioned correctly.
“It’s highly unusual for significant cardiac disease to be present without a murmur, a change in heart rate or a change in heart rhythm.”
Murmurs, he said, should be measured for intensity, timing, loudness and consistency.
“If heart disease is strongly suspected then an echocardiographic exam should be recommended, particularly if the murmur becomes louder over time or suddenly changes and there are other signs consistent with congestive heart failure on physical examination.
“Most murmurs are relatively benign and have little impact of performance or life span. But horses with clinical signs of congestive heart failure or suspected pulmonary hypertension are unsafe to ride. Veterinarians must advise owners not to ride these horses and the risks involved if they do.”