Delayed Diagnosis of Right Heart Failure Due to Sinus Venosus Atrial Septal Defect, Persistent Left Superior Vena Cava and Partial Anomalous Pulmonary Venous Return

Abstract

Sinus venosus atrial septal defects (SVASD) are uncommon and often underdiagnosed as they are visualised poorly on transthoracic echocardiography (TTE). A 59-year-old man was referred following worsening dyspnoea. A TTE demonstrated dilated right chambers, with torrential tricuspid regurgitation and a dilated coronary sinus. Agitated saline test raised the suspicion of both persistent left superior vena cava (PLSVC) and an intracardiac shunt, despite interrogation of the interatrial septum not demonstrating any defects. CT imaging of the thorax was performed revealing a superior SVASD alongside a PLSVC, and partial anomalous pulmonary venous return. SVASD are considerably uncommon, compared to other types of atrial septal defects (ASD). TTE has poor sensitivity in diagnosing SVASD, highlighting the importance of multimodality imaging in such cases. The purpose of this case report is to highlight unique features demonstrated on TTE, especially during the agitated saline study, which showcased the presence of a PLSVC alongside an intracardiac shunt that was undetected through conventional TTE alone.