Right ventricular growth potential in neonates with pulmonary atresia and intact ventricular septum.

The cardiac catheterization data and angiograms of 30 infants with pulmonary atresia and intact ventricular septum were reviewed to evaluate the growth potential of the right ventricle after transventricular pulmonary valvotomy. An index of right ventricular size based upon the tricuspid valve anulus, right ventricular inlet, and right ventricular outlet dimensions was used. Fourteen infants (Group I) were treated with systemic-pulmonary arterial shunts only, whereas 16 infants (Group II) underwent pulmonary valvotomy and 14 had shunting as well. Follow-up studies demonstrated the lack of right ventricular growth in Group I (right ventricular index of 7.0 +/- 3.2 preoperatively versus 7.0 +/- 2.0 postoperatively) and persistence of severe right ventricular hypertension (systolic pressure of 121 +/- 31 versus 120 +/- 48 mm Hg). In contrast, the right ventricular cavity increased in nine of 11 Group II infants who underwent valvotomy. Right ventricular index increased from 7.7 +/- 1.6 to 11.0 +/- 3.1 (p less than 0.01) and systolic pressure fell from 132 +/- 31 to 83 +/- 50 mm Hg (p less than 0.1). Early and late mortality in Group I was 50% (7/14), whereas only three of 16 Group II infants died (p greater than 0.1). It is concluded that pulmonary valvotomy should be attempted in all neonates with pulmonary atresia and intact ventricular septum in whom an outflow tract is identified angiographically to maximize the potential for right ventricular growth and increase its functional contribution to normal circulation.