Aortic stenosis in a dog.

A case of valvular aortic stenosis in a dog is described. The presenting sign was syncope during exercise. An unusual feature was right bundle branch block electrocardiographic pattern. During syncope electrocardiograms usually indicated atrial standstill and always had sever ST segment changes indicative of myocardial ischaemia. Pathological findings included chronic valcular changes which did not appear to be the result of a infectious inflammatory condition.