Patent Ductus Arteriosus

The ductus arteriosus originates just to the left of the PA bifurcation and inserts into the aorta slightly distal to and opposite from the ostium of the left subclavian artery. Given this posterior location, it is difficult to image a patent ductus arteriosus (PDA) itself with 2D TTE alone, and TEE is usually superior for direct visualization of the lesion574 Fig. 13-115^4 and B,

Plate 71). In most cases, 2D imaging of the communication is not essential, as color-flow Doppler reliably detects high-velocity diastolic flow within the PA in nearly all non-Eisenmenger patients.575-577 The flow jet characteristically enters the distal left region of the main PA and streams anterior along the medial wall of the vessel Fig. 13-115.B, Plate 42B). With large shunts, volume overload and subsequent dilation of the left ventricle occurs. Aortopulmonary window is a much rarer shunt involving the great vessels which presents as a communication anteriorly between the ascending aorta and proximal PA.578,579 It is embryologically distinct from a PDA and more closely related to a truncus arteriosus defect.

Venous Inflow Abnormalities

Anomalous pulmonary venous return (APVR) may be partial or total. Partial APVR is present in 80 percent of sinus venosus ASD cases and is a feature of the Scimitar syndrome.580,581 The usual finding on TTE is RV volume overload. TEE is quite useful in detecting these abnormal venous connections. In total APVR, the pulmonary veins may empty directly into the right atrium or into a common posterior chamber or vein. This structure and its connection with the right atrium may be visualized echocardiographically, along with the obligatory ASD.582-585 In some cases, the collecting chamber posterior to the left atrium may mimic the appearance of cor triatriatum, an entity characterized by a membrane in the posterior left atrium which may obstruct pulmonary venous inflow, causing symptoms similar to those of mitral stenosis586 (Fig. 13-116).

Cor Triatriatum Tee

Figure 13-116: Transverse transesophageal image of cor triatriatum. A membrane (arrows) is present in the left atrium. RV = right ventricle; RA = right atrium; LA = left atrium; LV = left ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

Figure 13-116: Transverse transesophageal image of cor triatriatum. A membrane (arrows) is present in the left atrium. RV = right ventricle; RA = right atrium; LA = left atrium; LV = left ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

Persistent left superior vena cava occurs in 0.5 percent of the normal population.587,588 In most cases, the anomalous vein empties into the coronary sinus, which then drains into the right atrium (Fig. 13-117). Unless the coronary sinus is unroofed and drains into the left atrium, no shunting occurs. The typical echocardiographic finding is a large coronary sinus, which is especially well seen on transesophageal or parasternal transthoracic views. The diagnosis may be confirmed by intravenous contrast injection from the left arm, as this will opacify the coronary sinus shortly before filling the right atrium.587,588

Coronary Sinus

Figure 13-117: A. Transesophageal image (transverse plane) from a patient with persistent left superior vena cava. The coronary sinus (CS) is dilated. B. After injection of agitated saline into the left antecubital vein, contrast is seen entering the right atrium (RA) via the CS. TV = tricuspid valve; RV = right ventricle; LV = left ventricle. (From Blanchard DG, DeMaria AN. Cardiac and extracardiac masses: Echocardiographic evaluation. In: Skorton DJ, Schelbert HR, Wolf GL, Brundage BH, eds. Marcus' Cardiac Imaging, 2d ed. Philadelphia: Saunders; 1996:452-480, with permission.)

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