RESUMEN
OBJECTIVES: To study forms of congenital heart disease present in a family of beagle dogs with a strong prevalence of ventricular septal defect and to document the pathological findings associated with the ventricular septal defects and investigate the mode of transmission. METHODS: The animals were investigated by physical examination, radiography, electrocardiography and ultrasonography to diagnose the presence of congenital heart disease. Some animals were diagnosed at post-mortem examination and the dead animals underwent post-mortem examination to verify the presence of ventricular septal defect. An analysis of pedigree was undertaken and two of the affected animals were mated to investigate the mode of transmission. RESULTS: Among the 28 dogs evaluated clinically or by post-mortem examination, 14 cases of ventricular septal defect were identified. The post-mortem examination showed some abnormalities of the ventricular outflow region associated with malformation of conotruncal septum development. When two affected dogs were bred, congenital heart disease was present in all of the offspring. CLINICAL SIGNIFICANCE: The congenital heart disease identified in this beagle family can be classified as conotruncal malformation, and an autosomal recessive mode of inheritance was suggested by pedigree analysis.