Figure legends
Figure 1. Preoperative imaging of arterial septal aneurysm.
Multi-slice computed tomography shows giant ASA is protruding into right atrium and thrombus attached to left side of ASA pouch (A). Transthoracic echocardiography shows ASA attached to right atrial free wall and protruding into right atrium (B). ASA, atrial sepal aneurysm; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.
Figure 2. Intraoperative imaging findings.
Giant atrial sepal aneurysm protrudes into right atrium (A). Patent foramen ovale (B). ASA, atrial sepal aneurysm; RA, right atrium
Figure 3. Pathological findings of atrial sepal aneurysm (ASA).
Bloodstained gauze was placed inside giant ASA to understand nature of thin tissue. Mixture of thickened and very thin tissues that seemed vulnerable to imminent tears (A). Histological section of thin ASA tissues (B). Histological section of normal ASA tissues mixed with fatty cell infiltration and fibrosis (C). Hematoxylin and eosin staining. Magnification, ×100. ASA, atrial sepal aneurysm.