Pulsed Doppler echocardiographic detection of obstruction of systemic venous return after repair of transposition of the great arteries.

Pulsed Doppler echocardiography (PDE) allows the detection of direction and quality (smooth vs disturbed, or "rough") of blood flow characteristics at known sites within the heart and great vessels.In order to test the ability of this technique to detect obstruction of systemic venous return after interatrial repair of transposition of the great arteries, twelve children who had undergone such surgery were examined by PDE.The blood flow characteristics in the systemic venous return atrium in the children were compared with invasive pressure measurements in the venae cavae and systemic venous return atrium.Six children without measurable baffle gradients had phasic diastolic flow characteristics in the systemic venous return atrium similar to the normal.All six children who had a gradient between the cava and systemic venous return atrium of 3 mm Hg or more had nonphasic disturbed blood flow in the systemic venous return atrium during diastole.We conclude that 1) PDE offers simple and specific detection of atrial flow patterns in infants who have had interatrial repair of transposition of the great arteries; 2) the detection of nonphasic disturbed atrial flow during diastole strongly suggests the presence of obstruction to systemic venous return; and 3) the detection of phasic atrial flow suggests the absence of significant obstruction.DURING INTERATRIAL repair of transposition of the great arteries (TGA), care is taken to avoid obstruction or narrowing of the venous channel.Even so, obstruction to venous channels does occur and may be severe enough to require reoperation.Invasive studies may be required to detect or assess such obstruction.We here report the use of pulsed Doppler echocardi- ography (PDE) as a noninvasive tool for the detection of narrowing or obstruction of systemic venous return after interatrial repair of TGA.PDE is a recently developed adjunct to traditional echocardiographic techniques and is described in detail elsewhere.'The PDE examination is performed with a hand-held transducer, in a fashion very similar to the traditional M-mode echocardiographic ex- amination.The transducer emits a series of pulses, and as the pulses are back-scattered from within the heart, the PDE unit compares the frequency of the back-scattered pulses with the frequency of emitted pulses.If the "beam" of pulses has encountered a moving column of blood, the frequency of back- scattered and emitted pulses will differ, and a Doppler effect will be detected.For example, if the blood is moving away from the transducer, back-scattered pulses will have a lower frequency than emitted pulses, and the PDE unit will record flow as being directed away from the transducer.In this way, the direction of blood flow is determined.The examiner can vary