Paradoxical Brain Embolism in Elderly Subjects with Small Atrial Septal Defects

Background: Atrial septal defects have a low prevalence in the general population, and are recognized as a rare cause of paradoxical brain embolism. Methods: We extensively examined stroke causes in patients with acute stroke admitted to a single stroke center within 1 year. Results: Among 186 consecutive patients, transesophageal or transthoracic echocardiography revealed 5 cases of paradoxical brain embolism: 3 (1.6%) were related to atrial septal defects, whereas 2 were patent foramen ovale patients. Although right-to-left shunt may have occurred after the development of acute pulmonary embolism in atrial septal defects case #1, the Valsalva maneuver elicited right-to-left shunt in atrial septal defects cases #2 and #3. The 3 cases were elderly (>60 years old), harbored small defects with normal systemic hemodynamics, and had not experienced any clinical symptoms related to atrial septal defects. Conclusions: Small atrial septal defect may cause paradoxical embolism as its initial related event, particularly in elderly subjects.