<International Circulation>:  Sinus venosus syndrome is a very specific condition， as is its correction. Firstly， can you give us a brief overview of the syndrome?

   Dr Uemura:  There is a spectrum of atrial septal defects (ASDs) but all have the feature of hemodynamic ASD. Sinus venosus is one of these characterized by more deviation to the venous side than normal central ASD and represents 4% of all ASD cases. Primum ASD occurs in 10% of overall defect cases and causes a deviation towards the inlet part of the ventricle. Due to the deviation there are specific issues for each presentation. For the sinus venosus ASD， it is usually located very near to the SVC and one or two pulmonary veins may be joined to the SVC because of that， and the sinus node which dominates the heart rhythm can be quite close to the surgical site. For the primum defect， because of the deviation towards the inlet part of the ventricle， almost always the inlet valves are involved. Morphologically speaking， the left or right side of that valve will not be normal and also the conduction system， the atrioventricular node， is very close to the defect. So we need to consider these structural issues.