Abstract
A dye-dilution study was carried out by injecting dye into the right and left atria through the dwelling polyvinyl tubings after open heart surgery and especially after the radical operation for tetralogy of Fallot.
In every instance time factors in both left and right atrial dye-dilution curves showed marked increase immediately after operation or on the first postoperative day. Subsequently they decreased first rapidly and later gradually. The changes were more marked in the right atrial dye-dilution curves than in the left ones.
Increase in all the time factors was apparently larger in tetralogy of Fallot than in ventricular or atrial septal defect. Particularly, disappearance time (tpd), time constant of exponential decay of the curve (ts) and mean transit time (_??_R) in the right atrial dye-dilution curves were markedly prolonged and furthermore a remarkable increase occurred in the right heart-pulmonary circulation time (_??_R-_??_L) and right heart-pulmonary blood volume (VRP).
Cardiac output after the operation was lower in Fallot's tetralogy than in other heart diseases. In two-thirds of the cases of Fallot's tetralogy, however, postoperative cardiac output exceeded 3.0l/min/m2 and attained a normal range.
The characteristic findings of the dye-dilution curves in tetralogy of Fallot were most closely related to the extent of residual pulmonary stenosis. This was indicated by a large systolic pressure gradient between the right ventricle and the pulmonary artery at the end of open heart correction.
