The availability of echo Doppler cardiography enables monitoring of the natural course of congenital aortic valvar stenosis more adequately than before. Between 1986 and 1993, 129 children with such stenosis were examined echocardiographically, 83 of them over a prolonged period with repeated studies of at least one per year. The pressure gradient between the left ventricle and ascending aorta, as well as the left ventricular wall thickness, were measured. When the pressure gradient detected increased to more than 60 mmHg, the patients were treated by balloon valvoplasty or surgical valvotomy. The last examination prior to intervention was taken as the final measurement.

We found a significant increase (≥10 mmHg) in the measured pressure gradient in 40 of the 83 patients (48%). The onset of severe stenosis was not observed at a specific age, rather the stenosis was found suddenly to increase in severity at any age. The gradients measured in children younger than 2 years of age, however, increased twice as rapidly as those measured in the older children. A high gradient was not always accompanied by evidence of left ventricular hypertrophy.

Based on our findings, we suggest that, since a sudden increase in severity of aortic valvar stenosis might be expected, the pressure gradient should be measured once every 6 months in children younger than 2 years of age and once a year after that age