Abstract WMP65: Left Atrial Enlargement Without Atrial Fibrillation: A Risk Factor for Ischemic Stroke?

Background: Left atrial enlargement without atrial fibrillation can be seen during evaluation of patients with cerebral ischemic events. However, it remains unclear whether such patients should be considered high risk for further cerebral ischemic events and may benefit from long term anticoagulation may be considered. Methods: We analyzed data from the Cardiovascular Health Study participants aged ≥65 years who underwent echocardiogram (included M-mode, 2-D, spectral, and color Doppler studies) and electrocardiogram (EKG) at baseline evaluation. All recordings were interpreted by central reader and left atrial diameter dimensions were recorded. We classified atrial dilation into four grades: 2.7-3.8 cm (ref), 3.9-4.2 cm (mild), 4.3-4.6 cm (moderate), and ≥4.7 cm (severe). We excluded patients with atrial fibrillation on EKG. Incident stroke was identified during annual follow-up examinations and at 6-month telephone contact and adjudicated by a central committee. Hazards ratio for all strokes, ischemic stroke, and hemorrhagic stroke during follow up were estimated using Cox proportional Hazards analysis. Results: Severe atrial dilation was observed in 298 (6.8%) of 4,384 study participants without atrial fibrillation (35.6% women, 2.3% African American; mean baseline age, 72.9 ± 5.2 years). The rate of ischemic stroke and any stroke was similar among patients with and without severe atrial dilation over a mean follow up period (mean ±SD) of 7.2 ±1 years. The risk of ischemic stroke (HR 1.3, 95% confidence interval [CI] 0.8-2.0) and all strokes (HR 1.2, 95% CI 0.8-1.8) was not different among patients with severe atrial dilation(compared with those without) after adjusting for age, race, gender, body mass index, heart disease, systolic blood pressure and cigarette smoking. The risk of hemorrhagic stroke (HR 1.1, 95% CI 0.3-3.6) was not significantly different among patients with and without severe atrial dilation. Conclusions: There was no increase in risk of any stroke or ischemic stroke in patients with severe atrial dilation without atrial fibrillation.