The purpose of this review is to outline the feasibility of performing a comprehensive atrial septal examination from the internal confine of the right atrium and to evaluate the advantages resulting by intracardiac echocardiography (ICE) evaluation of atrial septal morphology as well as pathophysiology. In this setting, ICE indications have not yet been established because ICE is a relatively new technique that is still evolving. Notwithstanding, during catheter-based secundum atrial septal defect and patent foramen ovale closure, ICE seems useful for diagnosing cardiac abnormalities instantly, guiding and monitoring all stages of the procedures, and assessing proper selection and optimal device placement. Moreover, ICE provides solid anatomical criteria to diagnose fenestrated atrial septal aneurysm, interatrial communications such as ostium primum and sinus venosus defects, partial anomalous pulmonary venous connection, and lipomatous hypertrophy of atrial septum.