Background
First described by Elliotson, infundibular pulmonary stenosis (IPS) refers to obstruction of outflow from the right ventricle (RV) within the body of the RV, as opposed to obstruction at the pulmonary valve, pulmonary artery (PA), or its branches. IPS often occurs in association with other intracardiac anomalies; isolated IPS is rare. In this article, IPS refers to isolated infundibular pulmonary stenosis with an intact ventricular septum.