How can something so small cause so much grief? Some thoughts about the underdeveloped right ventricle in pulmonary atresia and intact ventricular septum.

Over the past 2 decades several investigators (1-4) have attempted to demonstrate with a variety of methodologies that the morphologically right ventricle in p miens with either pulmonary atresia or critical pulmonary stenosis can grow after surgical intervention . That growth should occur in a morphologically right ventricle whose dimensions are nearly normal or in an occasional patient with a very small tight ventricle is not surprising, provided that there is adequate relief oft he severe obstruction to the right ventricular outlet tract . locked, perhaps in some patients with pulmonary atresia and intact ventricular septum, growth may seemingly result from resolution of massive ventricular hypertrophy and secondary attenuation of the functional cavity . (Most of my comments in this editorial will focus on enlu with pulmonary atresia and intact ventricular septum because data from the Congenital Heart Surgeons Study [Kirklin JW. Unpublished observations] suggest that for patients with critical pulmonary stenosis, including those with a small right ventricle, pulmonary valve balloon valvuloplasly has proved very effective in treating the basic nature of the disorder.) The classic determination of right ventricular growth in patients with pulmonary atresia and intact ventricular septum has been based on angiographicallv derived right wen . tricular volumes calculated by the Simpson technique This methodology has come under particular criticism and scrutiny because of the unusual shape of the morphologically right ventricle in these patients. the dtstoetitan of the normal trabecular zone by hypertrophy and its functional attenuation or obliteration by muscular overgrowth (2) . Furthermore, it has been difficult to accurately