Fig. 3

Measurements made in the TEE mid-esophageal bicaval view (90–120°): (A) Size of right atrial opening: the widest distance between the primary septum and secondary septum was measured perpendicular to the interatrial septal plane. (B) Size of left atrial opening: the widest distance between the primary septum and secondary septum was measured perpendicular to the interatrial septal plane. (C) Tunnel length: the length of overlap between the primary septum and secondary septum was measured parallel to the interatrial septal plane. (D) Secondary septum thickness: the width of the thickest point on the middle to lower segment of the secondary septum was measured perpendicular to the secondary septum. PFO, Patent foramen ovale; LA, Left Atrium; RA, Right Atrium; SS, Secondary septum.