Left Atrial Appendage Dimensions Predict the Risk of Stroke/TIA in Patients With Atrial Fibrillation

Methods: The study included 144 patients with nonvalvular AF who were not receiving warfarin and who underwent MRI/MRA prior to catheter ablation for AF. LAA volume, LAA depth, short and long axes of LAA neck, and numbers of lobes were measured. Results: Of the 144 patients, 18 had a prior stroke or transient ischemic attack (TIA) (13 and 5, respectively). Compared with patients who had no history of stroke/TIA, these patients were older, had higher prevalence of hypertension and hyperlipidemia and had higher LAA volume (22.9 +/- 9.6 cm3 vs. 14.5 +/- 7.1 cm3, P < 0.001). Their LAA depth (3.76 +/- 0.9 cm vs. 3.21 +/- 0.8 cm, P = 0.006) and the long and short axes of the LAA neck (3.12 +/- 0.7 cm vs. 2.08 +/- 0.7 cm, P < 0.001; 2.06 +/- 0.5 cm vs. 1.37 +/- 0.4 cm, P < 0.001, respectively) were larger. Using stepwise logistic regression model, the only statistically significant multivariable predictors of events were age (OR = 1.21 per year, 95% CI 1.06-1.38, P = 0.004), aspirin use (OR = 0.039, 95% CI 0.005-0.28, P = 0.001), and LAA neck dimensions (short axis x long axis) (OR = 3.59 per cm2, 95% CI 1.93-6.69, P < 0.001). Conclusion: LAA dimensions predict strokes/TIAs in patients with AF. LAA assessment by MRI/MRA can potentially be used as an adjunctive tool for risk stratification for embolic events in AF patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 10-15, January 2011).