A survey on the prevalence of heart murmurs in polo horses

Background: Cardiac murmur and subsequently cardiac failure is one of the poor-performance causes in athletic horses. Attention to murmur character is vital during heart examination. Polo is a sport which demands very high stress on horses, which may result in more stress on cardiovascular system. Objectives: In this study we assume that high pressure on polo horses makes them more susceptible to valves insufficiency as a result of high velocity across valves. Methods: 136 polo horses were evaluated in this study, and all participated in polo matches. Both sides of chest were heard carefully by two clinicians and murmur characters recorded in detail. Afterward the accuracy of auscultation finding was proved by echocardiography, in echocardiography examination all the valves were evaluated carefully for any trace of regurgitation or stenosis across valves. Results: Forty-seven horses showed cardiac murmurs during auscultation (34.55%). Thoroughbred had the highest rate of murmur, with 71% of murmurs observed in this breed. Grade 2 murmurs were more frequent than others and 24 horses showed Grade 2 murmurs. And tricuspid had the highest involvement and 24 horses had tricuspid regurgitation. Conclusions: This study is the first report of cardiac murmur in Polo horses, which showed the high presence of tricuspid and aortic murmur. The difference between prevalence of murmurs in this study and other ones was not remarkable