A practitioner's approach to canine cardiology.

Abstract

Abstract This paper is intended to be a guide for the practitioner to the diagnosis, prognosis and treatment of heart disease in the dog. Diagnosis and treatment of heart disease is based on a thorough clinical examination specifically auscultation of the chest and examination of the pulse augmented by radiography and electrocardiography. Cardiology is an exciting subject and recent advances in therapy have improved not only the life expectancy of dogs with heart disease but also the quality of life. The most important factor is to recognize that the problem is cardiac in origin. The elderly animal with a cough and a heart murmur must be examined and investigated thoroughly before assuming that the murmur and cough are connected. Overall incidence of heart disease has been estimated at 11 · 3% with the congenital type accounting for 0 · 5% (Detweiler & Patterson, 1965) . Congenital heart disease should be detected early in life, and certainly no later than at presentation of the puppy for primary vaccination, but will only be diagnosed if the puppy is thoroughly auscultated. The more common congenital cardiac defects, in approximate order of incidence, are patent ductus arteriosus, pulmonic stenosis, aortic stenosis, persistent right aortic arch, ventricular septal defect, tetralogy of Fallot and atrial septal defect (Patterson, 1965) . Early diagnosis is important as, particularly with patent ductus, surgery performed at an early stage can be curative. Pulmonic stenosis can also be treated surgically and successful treatment of tetralogy of Fallot using cardiopulmonary bypass has been reported (Herrtage, Hall & English, 1983) . Septal defects are also amenable to treatment by using cardiopulmonary bypass. Persistent right aortic arch will not cause a heart problem but vomiting will occur in the young dog. Chronic valvular fibrosis with mitral, followed by tricuspid, insufficiencies is the most usual acquired heart disease. It has been estimated that in dogs over eight years old 70% are likely to suffer from valvular heart disease but not necessarily showing clinical signs.