There are often unanswered questions and on occasion actual misdiagnosis when only transthoracic images are employed. Transesophageal echocardiography is a valuable adjunct to visualize the pulmonic leaflets easily answering the question whether they are too thick and dysplastic for a successful balloon valvuloplasty. The right ventricular outflow can be scanned tomographically by slowly pulling back the probe in the esophagus. The main pulmonary artery can be accurately measured for poststenotic dilatation. The pulmonary artery bifurcation can be inspected for peripheral stenosis.
Contrast is useful for demonstrating an associated atrial septal defect.
It is preferable to first employ contrast during the initial transthoracic evaluation rather than postpone it until the transesophageal study. Skipping this in the first patient resulted in a missed diagnosis of a large atrial septal defect. We think it also made him lose any faith he had in our diagnostic capabilities. Color Doppler flow is less reliable than contrast since the elevated right atrial pressures tend to match the left atrial pressures with little, if any, Doppler evidence of flow acceleration across the defect. Pulmonic stenosis can be associated with other congenital heart defects.