[The natural course of great ventricular septal defect with pulmonary hypertension in childhood].

The development of pulmonary vascular resistance was studied in 33 children with large ventricular septal defects, whose first heart catheterization had been accomplished during the first year of life and who had been recatheterized at least once before surgery had been performed. In 6 children infundibular stenosis developed, which was already seen during the first investigation in 5 cases. The other 27 patients were divided into 4 groups according to the left to right shunt ( less than 60%' greater than 59%) and to the pulmonary arterial pressure (PPsyst: PSsyst less than 80 : 100; PPsyst: PSsyst greater than 79 : 100). The results show that secondary elevatin of pulmonary vascular resistance after an initial fall is a frequent phenomenon, but that in some cases pulmonary vascular resistance is never low. In some other cases pulmonary vascular resistance does not rise again after the initial fall inspite of a high left to right shunt, sporadically because the defect has become smaller. The results are not in full agreement with the concept of Hoffman and Rudolph, who generally postulate an initial fall of pulmonary vascular resistance and who concede a later elevation of pulmonary vascular resistance only as consequence of a secondary re-increase. The concept of Bloomfield, on the other hand, seems suitable to interprete the different patterns.