An Unusual Presentation of an Atrial Septal Defect

Abstract

Atrial septal defect (ASD) is one of the most common congenital cardiac anomalies found in the adult population. Most lesions are classified into ostium primum, ostium secundum, sinus venosus, and coronary sinus type by anatomic site of defect. A 38-year-old woman visited the cardiovascular department for further evaluation of ASD diagnosed by screening transthoracic echocardiography (TTE) during peripartum period. She had suffered from mild exertional dyspnea for several years. TTE showed ASD (suspicious sinus venosus type, defect size=0.97 cm), normal left ventricular function with paradoxical septal wall motion, right ventricular and atrial enlargement, mild pulmonary stenosis, and moderate tricuspid regurgitation. Right ventricular systolic pressure was 56 mmHg, so we could confirm moderate degree of pulmonary hypertension. In addition, left atrium looked like divided chamber by abnormal membranous structure (Fig. 1). For precise evaluation of the ASD, we carried out transesophageal echocardiography (TEE). TEE revealed 4.07 cm sized large ASD, so right atrium looked like single large chamber. Furthermore, membrane-like structures were persent in left atrum, so left atrium looked like divided chambers (Fig. 2). Patient underwent operation for ASD one month later, and the operator confirmed that the lesion was large secundum type ASD with anomalous structure in left atrium and performed autopericardial patch closure for large ASD. Follow-up TTE after operation showed membranous structure in left atrium without remnant shunt flow (Fig. 3). In conclusion, this case was thought to be unusually large ASD with membrane in left atrium. Fig. 1 Transthoracic echocardiography showed 0.97 cm sized atrial septal defect suspected to be sinus venosus type. Left atrium looked like divided chambers by abnormal membranous structure. Fig. 2 Transesophageal echocardiography demonstrated 4.07 cm sized large atrial septal defect and membranous structures divided left atrium into plural chambers. Therefore, it made atrial chambers of large right atrium and small left atrium. Fig. 3 Follow-up transthoracic echocardiography showed no remnant atrial septal defect, but left atrium still looked like divided chambers by membranous structure.