TTE and MDCT of a Patient With a Persistent LSVC and Unroofed CS Defect
(A) Transthoracic echocardiography (TTE) (apical 4-chamber view) demonstrating right-sided chamber enlargement. (B) After injection of agitated saline via the left arm, prominent contrast is seen in the left heart with minimal opacification of right-sided chambers. This confirms the presence of an unroofed coronary sinus (CS) defect. (C) After injection of agitated saline via the right arm, prominent contrast is seen in the right atrium and ventricle, with a small amount of bubbles seen in the left-sided chambers. This confirms the presence of a right-to-left intracardiac shunt. However, this finding is not specific for unroofed CS defects. (D) Note that the CS is not visualized in a true apical 4-chamber view, as illustrated in this multidetector cardiac computed tomography (MDCT) reconstruction, given the inferior and posterior location of the CS. A = anterior; L = left; LSVC = left superior vena cava; P = posterior; R = right.