Valvular pulmonary stenosis. Natural history and right ventricular function in infants and children.

The purpose of this study was the analysis of natural history and right ventricular function of infants and children with valvular pulmonary stenosis. Available for assessment were the pressures in the right ventricle and pulmonary artery in 5 infants and 13 children obtained at two cardiac catheterizations, performed at intervals of 2 to 12 years (mean: 6.5 years) apart, as well as quantitative angiocardiographic data in another group of 38 children. There was no change in the pressure gradient between the right ventricle and pulmonary artery (PG) between the two catheterizations for those with an initial PG of less than 50 mmHg; but a mean increase of 8.6 mmHg year-1 occurred in those with an initial PG of more than 50 mmHg. There were good correlations between increase of PG and the first (r = 0.704) and the second (r = 0.904) catheterizations. End diastolic and stroke volume were normal while end-systolic volume was smaller (P less than 0.01) and ejection fraction greater (P less than 0.01) than normal. The natural history of children with a PG of more than 50 mmHg seems to be different from that with a PG of less than 50 mmHg. In the former group the increase of PG is rapid while PG in the latter does not change over many years. Right ventricular function is usually not impaired in patients with moderate and severe valvular pulmonary stenosis in the pediatric age group.