Introduction: Atrioventricular septal defect (AVSD) is one of the most frequent congenital heart diseases, making up 7.5% of all developmental anomalies of circulatory system.
Material and methods: Sixty-seven children with the diagnosis of atrioventricular septal defect were hospitalised at the Department of Paediatric Cardiology, Medical University in Gdańsk, in 1993-1998. Patients' age ranged at diagnosis between 3 days and 17 years (mean age 35 months). The analysed group included 20 children with partial atrioventricular septal defect (group I) and 47 children with complete AVSD (group II). The diagnosis was based on anamnesis, physical examination, ECG, chest x-ray and echocardiography. Cardiac catheterisation and angiocardiography were performed in 28 children.
Results: On the basis of the results obtained, 6 children with Down syndrome were disqualified from the surgery due to persistent pulmonary hypertension. Fifty-nine children Ð including all the patients from group I (20) and 39 children from group II were qualified for operations in extracorporeal circulation. Two children from group II required ventilation with the mixture containing NO in the early post-operative period. There were 8 deaths (12%). Three children from group II died preoperatively due to severe generalised infection in early infancy and 5 infants from group II died immediately after operation. No deaths occurred in group I. In one case of a 4 year-old boy with partial atrioventricular septal defect, atrioventricular block developed immediately after surgery and required constant stimulation of the heart. In two children it was necessary to replace mitral valve (2 and 5 years after ASD I surgery).
Conclusions: 1. Children with Down syndrome require screening echocardiography. 2. Non-invasive diagnostic examinations of atrioventricular septal defect are usually sufficient for the full assessment of the defect and the choice of further treatment. 3. The correction of the congenital heart disease such as atrioventricular septal defect should be completed in the first 6 months of life, particularly in children with complete AVSD.

Keywords: Down Syndrome, qualification for cardiac surgery, atrioventricular septal defect