Abstract 2349: Atrial Fibrillation or Flutter is Found in 45.4% of Elderly Patients with Nonhemorrhagic Stroke
The incidence of stroke in patients(pts) with diagnosed atrial fibrillation or flutter (AF) is well known but, because AF that is associated with stroke may be intermittent and not diagnosed, the role of AF in pts with nonhemorrhagic stroke remains unclear. To obtain data on the importance of AF in ischemic stroke pts we reviewed the clinical records and all the ECGs in a 14 year institutional data base of all pts admitted with nonhemorrhagic stroke to HUMC from 1/1/2005 to 12/31/2007. To determine if AF is more frequently the cause of stroke in the elderly we studied the nonhemorrhagic stroke pts ≥ 75 Y.O. and determined the incidence of CHADS2≥2 and of echo abnormalities in these elderly pts. Of 987 pts with ischemic stroke 310 pts (31.4%, 95% confidence limits 28.6, 34.4) had AF. Of these 987, 529 pts were ≥75 years of age; 240 of these elderly stroke pts had AF (45.4%, CL 41.2, 49.6). This was significantly more than the 15.2% incidence of documented AF in pts < 75 (p<.0001). In the pts ≥75 who had AF, CHADS2 was ≥2 in 220 pts, 91.67% (CL 87.5,94.5); 17 of the remaining 20 pts had echocardiograms and 12 had left atria or left ventrcular enlargement or ejection fraction <50%. Hence 97.89 % of these elderly stroke pts with AF had CHADS 2 or echo abnormalities. These findings that AF is found in over 31% of ischemic stroke pts suggests that AF is more commonly the cause of, or mechanism for ischemic stroke than previously thought, especially in the elderly with over 45% of stroke pts over 74 having AF. AF and associated emboli may be the mechanism whereby the stroke risk factors (hypertension, heart failure, diabetes and advanced age) cause stroke. Because the diagnosis of AF made from the ECG database was serendipitous and not prospective, it is likely that the incidence of AF is even higher. In pts with intermittent AF the frequency of episodes and time in AF increase as they age; the serendipitous diagnosis of intermittent AF from an ECG data base is less likely in younger pts. The finding that 91% of these elderly stroke pts with AF had CHADS2 abnormalities supports the value of this index in determining which pts should be anticoagulated. By adding the presence of echo abnormalities we have defined the population of AF pts that includes 97.9% of the pts who may go onto stroke and who will benefit from anticoagulation. Nonhemorrhagic stroke pts with these risk factors who do not have diagnosed AF should be meticulously studied to rule out AF, since anticoagualtion in pts found to have AF will markedly lessen the incidence of a recurrent stroke.
Conclusions: AF is very commonly found in pts with nonhemmorrhagic stroke, especially in the elderly, and is probably the mechanism whereby many of the stroke risk factors cause stroke. Stroke pts with CHADS2≥2 or echo abnormalities who have not had AF diagnosed should be meticulously studied for occult intermittent AF so they can receive anicoagulation to prevent a further stroke.
- © 2012 by American Heart Association, Inc.