Frequency of atrial septal aneurysms in patients with cerebral ischemic events

Background-Atrial septal aneurysm (ASA) is a putative risk factor for cardi oembolism. However, the frequency of ASA in the general population has not been adequately determined. Therefore, the frequency in patients with cereb ral ischemic events, compared with the frequency in the general population, is poorly defined. We sought to determine the frequency of ASA in the gene ral population and to compare the frequency of ASA in patients with cerebra l ischemic events with the frequency in the general population. Methods and Results -The frequency of ASA in the population was determined in 363 subjects, a sample of the participants in the stroke Prevention: Ass essment of Risk in a Community study (control subjects), and was compared w ith the frequency in 355 age- and sex-matched patients undergoing transesop hageal echocardiography in search of a cardiac source of embolism after a f ocal cerebral ischemic event. The proportion with ASA was 7.9% in patients versus 2.2% in control subjects (P=0.002; odds ratio of ASA, 3.65; 95% CI, 1.64 to 8.13, in patients versus control subjects). Patent foramen ovale (P FO) was detected with contrast injections in 56% of subjects with ASA. The presence of-ASA predicted the presence of PFO (odds ratio of PFO, 4.57; 95% CI, 2.18 to 9.57, in subjects with versus those without ASA). In 86% of su bjects with ASA and cerebral ischemia, transesophageal echocardiography did not detect an alternative source of cardioembolism other than an associate d PFO. Conclusions-The prevalence of ASA based on this population-based study is 2 .2%. The frequency of ASA is relatively higher in patients evaluated with t ransesophageal echocardiography after a cerebral ischemic event. ASA is fre quently associated with PFO, suggesting paradoxical embolism as a mechanism of cardioembolism. In patients with cerebral ischemia and ASA, ASA (with o r without PFO) commonly is the only potential cardioembolic source detected with transesophageal echocardiography.