We performed transventricular pulmonary valvotomy as initial surgery in 22 consecutive patients with pulmonary atresia and intact ventricular septum who had a patent infundibulum. Nineteen patients also had placement of a central aortopulmonary shunt. All patients survived surgery, and 16 patients have had preoperative and later postoperative catheterizations. The purpose of this study was to determine the response of the right ventricle to transventricular pulmonary valvotomy with regard to relief of right ventricular hypertension and growth of the entire right ventricle, including tricuspid valve, right ventricular volume, and right ventricular outflow tract. Right ventricular systolic pressure decreased from 111.3 +/- 31.7 mm Hg before initial surgery to 65.6 +/- 26.2 mm Hg. Right ventricular end-diastolic volume increased from 59.1 +/- 39.3% of predicted normal before initial surgery to 114.6 +/- 63.2% at late follow-up catheterization. Tricuspid valve anulus circumference also increased in size from 73.2 +/- 21.3% of predicted normal before initial surgery to 90.4 +/- 22.8% at late follow-up catheterization. Only one patient (6%) required a transanular right ventricular outflow tract patch at the time of biventricular repair. Twenty of 22 patients (91%) either have had or are awaiting biventricular repair. We conclude that transventricular pulmonary valvotomy and central aortopulmonary shunt can be performed safely in newborn infants with pulmonary atresia and intact ventricular septum who have a patent infundibulum. Effective valvotomy relieves right ventricular hypertension, allows for excellent right ventricular and tricuspid valve growth, and optimizes potential for biventricular repair.