Indirect radiographic and angiographic signs of isolated left superior vena cava in congenital heart disease.

Blood that drains into the right atrium through an isolated left superior vena cava (LSVC) can be a complicating condition during cardiac surgery. In cases of LSVC, a double shadow can be present on standard chest X-ray over the left mediastinum. A notch along the lower contour of left atrium has been previously reported by Owen et al. in 4 cases as an indirect sign of this LSVC anomaly. These two indirect signs were evaluated in 135 (4.5%) cases of LSVC, viewing 89 chest radiographs and 40 angiograms. Their incidence, separately (17-45%) or in combination (9-20%), was observed to be frequent enough to justify a systematic search of these signs in open-heart surgery candidates.