Unusual Case of Anomalous Pulmonary Venous Return With Left Atrial to Systemic Venous Shunt
A 5-year-old boy with an intermittent systolic heart murmur at routine pediatric checkups and an incomplete right bundle-branch block on ECG and with no other past medical history and a normal exercise tolerance presented for echocardiographic evaluation. Echocardiography showed a volume-loaded right ventricle (RV) and right atrium, a patent foramen ovale, and reversal of flow in the right upper pulmonary vein (RUPV). As these views were limited, we proceeded to perform a transesophageal echocardiogram (TEE) and a cardiac catheterization to clarify the anatomy. TEE showed normal connection of all 4 pulmonary veins and significant reversal flow from the left atrium (LA) into the RUPV. Angiograms performed to further clarify the morphology showed a partial anomalous venous return from the right upper lobe into the superior vena cava (SVC), as shown in Figure 1A and Movie I. Figure 2 illustrates a normal RUPV with correct discharge into the left atrium that gives rise to an abnormal branch connecting the RUPV to the SVC. Pressure differences caused a left-to-right shunt from the LA to the SVC, with reversal of flow in the proximal RUPV. This resulted in the hemodynamics of an atrial septal defect with a volume-loaded RV but intact atrial septum. This finding was initially counterintuitive because the pulmonary veins were seen to be normally connected in TEE. Angiography clarified this unique morphology, which has never been described before (Figures 2, 1B, and 1⇓C; Movies II and III). In cases of volume-loaded RV with intact atrial septum and normally connected pulmonary veins, it is crucial to determine the flow direction in the pulmonary veins to rule out this rare anomaly.
The online-only Data Supplement, which contains 3 movies, can be found at http://circ.ahajournals.org/cgi/content/full/113/22/e840/DC1.