Introduction

Patent foramen ovale (PFO) is a common finding, occurring in up to 25% of people.1 ,2 An association between PFO and stroke has consistently been seen in up to 50% of patients without an identifiable cause, that is, the so-called cryptogenic stroke (CS) and only in 20% with an identified cause.3 ,4 Many studies have been published testing the hypothesis that paradoxical emboli through a PFO may be implicated, however the available evidence is mixed and conflicting,5 ,6 perhaps in part due to the low recurrence rate and long-term nature of these events. PFOs are associated with numerous other conditions including migraine with aura, decompression sickness, other venoarterial embolic phenomena and platypnoea orthodeoxia.

In this review we will describe the embryological development of the interatrial septum, discuss the diagnosis and clinical associations of PFO, as well as evaluate the available data for and against closure.