8.1.1 General considerations
Cardiac murmurs and arrhythmias are frequently detected at a pre-purchase examination and may be a cause of concern for the examining veterinary surgeon. Most often, normal functional murmurs and physiological arrhythmias, which have no bearing on the suitability of the animal for any athletic use, will be present. On other occasions, the findings may indicate the presence of underlying pathology which may or may not have a significant effect on the horse's future use.
At a pre-purchase examination, a veterinary surgeon is asked for an opinion regarding the suitability of an animal for a specified intended purpose. This is a matter of judgement; there are no hard and fast rules. Ideally, the judgement can be given in terms of the degree of risk that prospective purchasers would be taking if they bought the horse. However, the existing system means that the animal has to be recommended as suitable or unsuitable for whatever purpose, taking the specific findings into consideration. Obviously, veterinarians are concerned about the possibility of litigation if a problem ensues and someone else does not agree with their opinion.
The principal concerns at a pre-purchase examination are the future athletic performance of the animal and its safety as a riding animal. The veterinarian should make a reasoned judgement about the significance of cardiac disease depending on individual circumstances. One is not asked to give 100% guarand this should be made clear. To regard all animals with cardiac muror arrhythmias as unsuitable for purchase would not be in the interests of prospective purchasers. If the clinical approach is sound, the findings are accurately recorded and the situation fully explained, then the best interests of all are served. The ground rules for the pre-purchase examination are therefore similar to those in the clinical evaluation of an animal which is presented for poor performance or other clinical signs which may relate to heart disease; the essential step is to establish a specific diagnosis. This can normally be based on careful examination and auscultation (Chapter 3). Sometimes, further diagnostic aids such as echocardiography and electrocardiography may be required to confirm a diagnosis and aid judgement of the severity of the condition. Unforless emphasis can reliably be placed on the clinical history at prethan during a conventional examination.
Once it has been established that a pathological process is present, the next step is to determine the significance of the problem. This primarily depends on the extent to which cardiovascular function is affected. However, at a preexamination it also depends on the level of athletic activity which the horse is likely to perform and the specific requirements of the potential purchaser. Seldom do two owners have exactly the same requirements.