During @ years of mean follow-up , first occurrence of stroke , transient ischemic attack , or systemic embolism occurred in @ patients.The strongest independent predictors of embolic events were age @ years ( hazard ratio @ ; confidence interval , @-@ @ ) , prior stroke or transient ischemic attack ( hazard ratio @ ; @ % confidence interval , @-@ @ ) , and female sex ( hazard ratio @ ; confidence interval , @-@ @ ) .