Findings in 261 cardiac examinations of warmblood sport horses and their association with performance.

The prevalence of cardiac findings and their influence on the performance potential of warmblood sport horses is widely debated. This paper evaluates the frequency and correlation of valvular regurgitations, dimensional changes, and arrhythmias in 261 warmblood sport horses retrospectively. These horses were examined because of clinical complaints (e.g., poor performance) or due to murmurs or arrhythmias detected as an incidental finding. Frequency analysis showed that mitral valve regurgitation was the most common valvular regurgitation in our population (n = 194), followed by regurgitations of the aortic valve (n = 46). Dimensional changes of the left atrium were associated with an increased risk of atrial fibrillation (OR = 3.18, p = 0.05). Furthermore, their possible influence on performance was assessed. If the heart was detected as the cause of an exercise intolerance by exclusion of other pathologies (n = 39), atrial fibrillation was the most frequent finding. Other cardiac findings discovered frequently in horses with poor performance were severe MVI, severe TVI, AVI, and ventricular and supraventricular premature complexes. However, most horses presented for cardiac examination did not show any clinical signs of cardiac disease (n = 176), and the pathologies described were in most cases incidental findings. Therefore, we can state that mild and moderate valvular regurgitations are in most cases of little clinical relevance. However, valvular regurgitations are associated with an increased risk for the development of dimensional changes. The latter are associated with the development of atrial fibrillation, which is the cardiac finding most associated with a reduced performance potential of the horse affected. [ABSTRACT FROM AUTHOR]