Natural history of valvular pulmonary stenosis in children below the age of two years. Long-term follow-up with serial heart catheterizations.

18 patients with mild and moderate valvular pulmonary stenosis diagnosed by heart catheterization before the age of 2 yr (mean 11.6 mth) were followed for 5 to 21 yr without operation. 15 cases had a repeat catheterization study after a mean interval of 10.7 yr. Of 7 cases with an initial right ventricular peak systolic pressure (RVSP) of 50 mm Hg or below, 6 had a decrease and 1 a moderate increase in RVSP. Of 8 cases with an initial RVSP of greater than 50 mm Hg 2 had a decrease, 2 had no change and 4 had a significant increase in RVSP; the latter subsequently underwent operation. Electrocardiography yielded some information, but neither roentgenography nor history was of any help in evaluating the severity of the stenosis at follow-up. As mild and moderate valvular pulmonary stenosis in infants and children below the age of 2 may progress and require operation a repeat heart catheterization is usually to be recommended later in childhood.