Obstruction of the left ventricular outflow tract in childhood--improved diagnosis by transoesophageal echocardiography.

We used transoesophageal echocardiography in 4 children with either documented or suspected obstruction of the left ventricular outflow tract to determine whether this technique may provide additional morphologic information when compared to praecordial ultrasound. Transoesophageal studies defined unsuspected mitral valvar abnormalities in two patients and involvement of the subvalvar mitral apparatus in one. In one patient, the study documented a suspected fibrous ridge associated with malalignment of the outlet septum. Transoesophageal echocardiography would appear to be a new technique with definite advantages in defining the spectrum of lesions which cause obstruction to the left ventricular outflow tract in children.