Equine Matters - Autumn/Winter 2017

3 EQUINE MATTERS Dr Keesjan Cornelisse DVM MS PhD Dipl.ACVIM MRCVS, Calweton Veterinary Group Veterinary surgeon Keesjan Cornelisse XLVets Equine practice Calweton Equine Besides a good clinical examination, a variety of further diagnostic tests are available including ultrasonography to look at the structure and valves of the heart, and electrocardiogram (ECG) to assess the electrical activity in the heart which stimulates the heart muscle to contract and thereby the heart to beat. Any underlying disease should be treated accordingly while the heart disease is managed. Horses may be born with a heart problem (congenital) or may acquire one later in life (acquired). The structure of the heart may be affected or it may be the ability of the heart to pump which is the problem. In some individuals, both of these may be involved. Like other species, congenital structural defects may present in various forms with ventricular septal defects (effectively a ‘hole in the heart’) being one of the more common problems. Acquired causes include ageing changes affecting the different components of the valves of the heart resulting in the valves themselves not working effectively and becoming leaky. Other less common causes of heart disease in horses include damage to the heart muscle (cardiomyopathy) from viral infection, damage to the valves from large amounts of bacteria in the bloodstream, consumption of toxins, and occasionally rupture of one of the heart’s internal structures. Imbalances of electrolyte concentrations in the blood may contribute to the heart’s rhythm being affected. Clinical signs can be varied from a mild cough to exercise intolerance, collapse or sudden death. Clinical signs may also be non-existent when horses are not strenuously exercised. Heart disease in horses is uncommon and the causes are numerous. The clinical signs can be non-existent, or can vary from a mild cough to tiring easily, collapse or even sudden death. Figure 1. Ultrasound is used to image the size of the heart and its chambers, and assess the competency of valves Assessment of heart disease in horses H E A R T D I S E A S E