In pediatric cardiology a datebase and supporting information system are indispensable in order to cunduct more extensive and detailed investigations. Diagnostic decision during the diagnostic process in congenital heart disease CHD must be supported by the diagnostic suitable decision support system. In the majority of children with CHD, the diagnosis should be possibly made before the complete diagnosis procedure has been accomplished, with maximal information and minimal risk for patient and doctor and cost benefit. We develop a tool called DIAPRO that supports all activities concerned with the menagement of the diagnosis process.