Background Neonates with critical pulmonary valve stenosis often demonstrate small or hypoplastic right ventricular structures. Relief of the obstruction enhances forward flow across the right ventricle and reduces its pressure load. Growth of the right ventricle and especially of the pulmonary valve annulus was evaluated after balloon dilatation.

Methods Ten consecutive neonates with critical pulmonary valve stenosis who underwent balloon valvuloplasty were studied by serial echocardiography to assess growth of right ventricular structures at follow-up.

Results The mean diameter of the pulmonary valve annulus increased from 6.1 ± 1.4 mm to 12.6 ± 3.5 mm (z scores from –2.9 ± 1.0 SD to –1.3 ± 1.2 SD, p < 0.0001) after a mean follow-up period of 2.7 ± 2.0 years. The mean diameter of the tricuspid valve annulus increased from 12.9 ± 3.8 mm to 19.0 ± 3.1 mm; however, the respective z score did not change significantly (from 0.5 ± 2.4 SD to –0.5 ± 1.0 SD). Right ventricular cavity size was hypoplastic in four patients initially and normal in all patients at latest follow-up.

Conclusions Balloon dilatation of critical pulmonary valve stenosis encourages catch-up growth of the pulmonary valve, and surgery may be avoided even in a hypoplastic pulmonary valve annulus. (Am Heart J 1998;136:276-80.)