Patent foramen ovale (PFO) and atrial septal aneurysm (ASA) have been identified as potential risk factors for stroke, but information about the risk of recurrent cerebral ischemia is scarce. The aim of this retrospective study was to assess the absolute risk of recurrent cerebrovascular events in 132 patients under 60 years of age with patent foramen ovale, atrial septal aneurysm (diagnosed by transesophageal echocardiography with a contrast study), or both and an otherwise unexplained stroke or transient ischemic attack (TIA). During a mean follow-up of 22.6 +/- 16 months, six patients had a recurrent stroke (n = 2) or a TIA (n = 4). No systemic embolism was observed. The actuarial risk of having a recurrent stroke was 2.3% (95% confidence interval, 0.6% to 8.2%) at 2 years, whereas the risk of having a stroke or a TIA was 6.7% (95% confidence interval, 3.1% to 14.2%) at 2 years. The average annual rates of recurrence were 1.2% and 3.4%, respectively. In patients with both PFO and ASA, the actuarial risk of a first recurrent stroke was 9.0% (95% confidence interval, 2.4% to 28.5%) at 2 years, with an average annual rate of recurrence of 4.4%. As a group, patients with patent foramen ovale, atrial septal aneurysm, or both and an otherwise unexplained stroke or TIA appear to have a low risk of recurrent stroke whatever the prophylactic antithrombotic therapy used. The association of ASA and PFO may be an indicator of a higher risk of recurrent stroke.