Echocardiographic diagnosis of partial obstruction of Blalock-Taussig shunts.

While echocardiography has previously been used to differentiate between patency and complete occlusion of aortopulmonary shunts, the echocardiographic diagnosis of partial obstruction of a shunt has not been reported. We describe a unique color flow Doppler finding that quickly and accurately diagnosed three cases of partial distal obstruction of aortopulmonary shunts.