Abstract 2930: Prevalence of Unrecognized Atrial Fibrillation and Stroke Risk in an Otherwise Healthy Population Over 40: A Significant Target for Stroke Prevention

Abstract

About 22% of AF-related ischemic stroke occurs in incidentally documented AF. This prompted us to determine the proportion of the general population that may have unrecognized Atrial Fibrillation (AF) and may therefore be at risk of stroke. We hypothesized that a significant proportion of those with incidentally found AF would have no symptoms and a CHADS2 score high enough to put them at risk of stroke. We reviewed surgical pre-admission ECGs, routinely performed in all patients over 40 years of age and examined medical records of those in AF. Of 1894 ECGs reviewed, 77 (4.1%) showed AF. Medical records of 53/77 (representing 1469 of the 1894 ECGs) were available for review but the study is ongoing. AF was incidentally found in 6/1469 patients (0.4%) and previously diagnosed in 47 (3.2%). The mean age of those in AF was 76 ± 9 and similar in incidental and previously diagnosed AF (74 ± 5 vs. 77 ± 9). Average CHADS2 score was high in both groups: 3.0 ± 1.7 in incidental AF and 2.4 ± 1.2 in previously diagnosed AF. Only 26/37 of those with previously diagnosed AF and CHADS2 score > or = 2 were on Warfarin, consistent with the known evidence-practice gap for thrombo-prophylaxis. The mean resting heart rate was 77 ± 16 in incidental AF, and 78 ± 18/min in previously diagnosed AF. Only 2/6 with incidentally discovered AF reported palpitations. AF is prevalent, and is unrecognized in about 1/200 of a relatively healthy population over 40. Unrecognized AF is generally unassociated with symptoms and resting heart rate is not elevated. Those with unrecognized AF usually have CHADS2 score high enough to warrant anti-coagulation, which suggests that there are appreciable numbers of the well elderly in the community who would benefit from AF recognition through simple detection programs such as feeling the pulse or recording an ECG, followed by thrombo-prophylaxis to prevent future stroke.