Insight in cardiac patients of a referral clinic: valvular regurgitations: will they become clinically relevant?

Abstract

A retrospective observational study among equine cardiac patients is performed including 603 horses. The study concentrated on the general characteristics, diagnoses and clinical relevance of the equine cardiac patients and the long-term prognosis for valvular regurgitations. The 603 horses included 60.0% geldings, 28.7% mares and 11.3 % stallions. Warmblood horses were with 76.8% the most prevalent breed and 69.5% of the studied population was 10 years of age or younger. In 586 horses an echocardiography was performed. Valvular regurgitations were with 55.3% the most frequent diagnosed condition, followed by horses with only flow murmurs or no abnormality found at all in 15.6% of cases. Valvular regurgitations combined with arrhythmias were diagnosed in 9.3% of horses, arrhythmia's alone in 6.1%, the diagnosis of myocarditis, endocarditis and pericarditis together in 4.6%, congenital abnormalities in 4.0%, aneurysms in 0.7%, and other diagnoses in 4.3%. In 11.9% of the 603 horses the cardiac condition was considered to be clinical relevant at the time of examination. For the evaluation of the long-term prognosis for valvular regurgitations, information is gained from 125 horses. The mean time between first examination and the follow-up was 6,7 ± 2,7 year (2,7-14,4) and consisted of 22 horses with small regurgitations, 60 with moderate and 43 with severe valvular regurgitations. The mean age of the horses at first examination was 9,9 ± 5,4 years (2,4 – 26,0). From the 125 horses 72 were kept in ownership while 30 had died or were euthanized for various reasons in between the examination and follow-up. In three horses signs of heart failure was present at the time of euthanasia according to the owner. From the 42 horses that were alive, 32 were in various uses as riding or breeding horses and the other 10 horses were retired. In none of these 42 horses did the owner reported clinical signs of cardiac failure in the horse under the current circumstances. If a horse with valvular regurgitations were to start showing signs of cardiac failure, it seems that a diagnosis of moderate or severe regurgitation must be accompanied by several other abnormalities including severely enlarged cardiac chambers or arrhythmias and this will likely take years. Clear signs of cardiac disease did not seem to show up in the 42 horses in an average of 6.5 years following the first diagnosis. How many years these horses can eventually cope with their cardiac condition and under what circumstances remains uncertain and should be further investigated.