Assessment of right ventricular outflow tract in children by two-dimensional echocardiography using a new subcostal view Angiocardiographic and morphologic correlative study

Abstract

Evaluation of the right ventricular (RV) outflow tract in congenital heart disease is extremely important for surgical management. Therefore, the value of 2-dimensional echocardiography (2-D echo) to assess the RV outflow tract was studied using a new approach: the subcostal elongated right oblique view. Twenty normal children and 49 children with congenital heart disease, aged 1 day to 11 years, were studied. Significant pulmonary infundibular obstruction was present in 22 patients with conotruncal malformations. To obtain the subcostal elongated right oblique view from the short-axis view at the aortic valve level, the transducer was slightly rotated clockwise with an anterior angulation of about 30° so that the ascending aorta was seen in its long axis, providing an image similar to that obtained by a right ventriculogram in the elongated right anterior oblique view. The deviation of infundibular septum was appreciated by measurement of the angle α, defined by the long axis of the infundibular septum and the plane of aortic cusps. This view could be obtained in 64 patients (92%). In correlation with angiographic or anatomic data, the subcostal elongated right oblique view permitted recognition of several types of RV outflow tract: type I—normally formed RV outflow tract; type II—disorganized RV outflow tract with obstruction (α <90°); type III and IV—disorganized RV outflow tract with obstruction (α >90°). This view could visualize the crista supraventricularis in type I, but also the anatomic components of RV outflow tract that may contribute to obstruction in the other types: infundibular septum, septoparietal trabeculations and trabecula septomarginalis. The subcostal elongated right oblique view was superior to standard 2-D echo views in imaging the RV outflow tract anatomy and defining the severity and type of infundibular obstruction. Thus, 2-D echo using the subcostal elongated right oblique view provides a safe, noninvasive technique for the serial evaluation of RV outflow tract in children both before and after surgical correction.