Patent foramen ovale and atrial septal defect.

Atrial septal defects (ASD) are among the most common congenital heart diseases encountered in adulthood. Patent foramen ovale (PFO) is present in up to 25% of the population. ASD could present as isolated lesion or in association with more complex congenital heart disease form as tetralogy of Fallot, or Ebstein's anomaly of tricuspid valve. There is a wide range of clinical presentation ranging from asymptomatic subjects surviving to adulthood undiagnosed to subjects presenting with right heart failure and severe pulmonary vascular disease (Eisenmenger syndrome). This manuscript is an in depth review of the complex atrial septation, the variable clinical presentation of ASD and PFO, and its clinical and therapeutic implications.