Frequency and direction of interatrial shunting in valvular pulmonic stenosis with intact ventricular septum and without left ventricular inflow or outflow obstruction. An analysis of 127 patients treated by valvulotomy.

This report summarizes observations in 127 patients who underwent pulmonic valvulotomy for valvular pulmonic stenosis with intact ventricular septum and without obstruction to left ventricular inflow or outflow. Of the 127 patients, 30 (24%) preoperatively by dye dilution curves had shunting at the atrial level: in 19 (63%), the shunt was right-to-left, and in the other 11 (27%), entirely left-to-right. The patients with right-to-left interatrial shunts had severe pulmonic valve stenosis (average peak systolic pressure gradient = 120 +/- 11 mm. Hg) and small (average diameter 1.1 +/- 0.1 cm.) sized defects in the atrial septum (patent foramen ovale). In contrast, the patients with left-to-right shunts had mild to moderate pulmonic valve stenosis (average peak systolic pressure gradient = 60 +/- 5 mm. Hg) and relatively large (average diameter = 2.8 +/- 0.1 cm.) defects in the atrial septum (true atrial septal defect). The patients with right-to-left interatrial shunts had no significant differences in right versus left atrial pressures. The patients with left-to-right interatrial shunts, however, had left atrial pressures significantly greater than right atrial pressures (7 +/- 0.5 vs 5 +/- 0.5, p less than 0.05). No significant differences were found in ventricular end-diastolic pressures.