Background: The medical literature contains conflicting reports on the association of left atrial (LA) enlargement with risk of stroke. The relation of LA size to risk of stroke and death in the general population remains largely unexplored.
Methods and results: Subjects 50 years of age and older from the Framingham Heart Study were studied to assess the relations between echocardiographic LA size and risk of stroke and death. During 8 years of follow-up, 64 of 1371 (4.7%) men and 73 of 1728 (4.2%) women sustained a stroke, and 296 (21.6%) men and 271 (15.7%) women died. Sex-specific Cox proportional-hazards models were adjusted for age, hypertension, diabetes, atrial fibrillation, smoking, ECG left ventricular (LV) hypertrophy, and congestive heart failure or myocardial infarction. After multivariable adjustment, for every 10-mm increase in LA size, the relative risk of stroke was 2.4 in men (95% CI, 1.6 to 3.7) and 1.4 in women (95% CI, 0.9 to 2.1); the relative risk of death was 1.3 in men (95% CI, 1.0 to 1.5) and 1.4 in women (95% CI, 1.1 to 1.7). Adjusting for ECG LV mass/height attenuated the relation of LA size to stroke and death.
Conclusions: After multivariable adjustment, LA enlargement remained a significant predictor of stroke in men and death in both sexes. The relation of LA enlargement to stroke and death appears to be partially mediated by LV mass.