Background and purpose: For optimal acute stroke management and secondary prevention, discrimination of stroke etiology is crucial. We hypothesized that a low Alberta Stroke Program Early CT Score (ASPECTS) on diffusion-weighted imaging (DWI) immediately after stroke onset was associated with the presence of atrial fibrillation (AF).
Methods: Consecutive patients admitted within 24h from stroke onset with an occlusion at the horizontal segment of the middle cerebral artery (M1) on initial MRA were retrospectively enrolled. AF was diagnosed based on continuous electrocardiogram monitoring during acute hospitalization or its confirmed history.
Results: Of the 206 patients (95 women, median age 77 [IQR 69-85] years, NIHSS score 18 [13-23]) enrolled, AF was identified in 138 patients (AF group): chronic AF in 89, known paroxysmal AF (pAF) in 13, and masked pAF on admission in 36. The ASPECTS score on the initial DWI, performed a median of 2.5h after onset, was lower in the AF group than in the others (4 [2-6] vs. 7 [4-8], p<0.001). With the optimal cut-off value of ≤ 6 (sensitivity, 78%; specificity, 57%; area under the ROC curve, 0.682), DWI-ASPECTS was independently associated with the presence of any AF (OR 5.05, 95%CI 2.36 to 10.8), as well as the presence of any pAF (OR 8.64, 95%CI 3.00 to 24.9) and that of masked pAF on admission (OR 10.0, 95%CI 3.06 to 32.9).
Conclusion: Extensive early ischemic change assessed by DWI-ASPECTS predicts the presence of AF, even initially masked pAF, in acute stroke patients with M1 occlusion.
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