Transthoracic (TTE) and transesophageal echocardiography (TEE) is the standard imaging method for atrial septal defect (ASD) and patent foramen ovale (PFO) detection, for patient selection for transcatheter ASD/PFO closure, for intraoperative guidance and for long-term follow-up. The size, shape, location and the number of the atrial communications schould be determined. The accuracy of PFO detection can be improved by using agitated saline together with maneuvers to transiently increase the right atrial (RA) pressure. The appearance of microbubbles in the left atrium (LA) within 3 cardiac cycles after opacification of the RA is considered positive for the presence of an intracardiac shunt. Three dimensional TEE identifies further septal fenestrations and describes the dynamic morphology of ASD/PFO and atrial septal aneurysm. Follow-up evaluations with TTE is recommended at 1, 6, and 12 months after the procedure, with a subsequent evaluation every year. Previous studies showed an increased incidence of atrial arrhythmias early after device closure. Speckle tracking analysis may help to understand functional left atrial remodeling following percutaneous closure and its impact on atrial arrhythmias.