Isolated right superior vena cava drainage into the left atrium diagnosed noninvasively in the peripartum period

Abstract

Isolated right superior vena cava drainage into the left atrium is an extremely rare cardiac anomaly, especially in the absence of other cardiac abnormalities. Only 28 of 5,127 reported consecutive congenital cardiac cases involved superior vena cava drainage into the left atrium, and all were associated with other cardiac anomalies. Of 19 reported cases of right superior vena cava drainage into the left atrium, most patients have been children who were experiencing mild hypoxemia and cyanosis. Herein, we describe the case of a 34-year-old woman who presented with asymptomatic hypoxemia in the peripartum period. She was diagnosed to have isolated drainage of the right superior vena cava into the left atrium. To the best of our knowledge, this is the 1st reported instance of such diagnosis by use of noninvasive imaging only, without cardiac catheterization. We also review the medical literature that pertains to our patient's anomaly.

Keywords: Anoxia/etiology; blood circulation; heart atria/abnormalities; heart defects, congenital/complications/diagnosis/pathology; magnetic resonance imaging; oxygen/blood; peripartum period; technetium/diagnostic use; vena cava, superior/abnormalities/radiography.

Fig. 1. Images from a ventilation–perfusion scan that was performed after technetium 99m macroaggregates were injected intravenously into the right upper extremity. Radiotracer activity within the lungs (black arrows) is due to distribution through the bronchial arteries. Systemic activity is most evident in highly vascular structures, including the thyroid gland (black arrowheads), spleen (white arrowheads), kidneys (white arrows), salivary glands (white bar-tailed arrow), and breast tissue (black bar-tailed arrows). LAO = left anterior oblique; LPO = left posterior oblique; LT LAT = left lateral; RAO = right anterior oblique; RPO = right posterior oblique; RT LAT = right lateral

Fig. 2. Steady-state, free-precession, paracoronal magnetic resonance image shows the superior vena cava (large arrow) and the left superior pulmonary vein (small arrow) emptying into the left atrium (asterisk). The inferior vena cava empties separately into the right atrium.

Fig. 3. Steady-state, free-precession, contrast-enhanced, coronal magnetic resonance image (maximum-intensity projection) shows contrast material in the superior vena cava (arrowhead), left heart (asterisk), and proximal aorta (arrow), without opacification of the right heart or the pulmonary vasculature.