Left Atrial Dilatation and Reduced Left Ventricular Ejection Fraction Are Associated With Cardioembolic Stroke

Objective: Left atrial (LA) dilatation and heart failure are independent risk factors for ischemic stroke. The goal of this study is to evaluate the association between LA dilatation and reduced left ventricular ejection fraction (EF) with cardioembolic stroke. Methods: Four hundred fifty-three patients with ischemic stroke admitted to the University of California, Irvine between 2016 and 2017 were included based on the following criteria: age >18 and availability of echocardiogram. Stroke was categorized into cardioembolic and non-cardioembolic. EF was categorized into normal: 52-72% (male), 54-74% (female), mildly abnormal: 41-51% (male), 41-53% (female), moderately abnormal: 30-40%, and severely abnormal: <30%. LA volume was categorized into normal (≤34 ml/m²) vs. enlarged (≥35 ml/m²). Other variables included gender, hypertension [systolic blood pressure (SBP) ≥ 140 or diastolic blood pressure (DBP) ≥ 90], and known history of atrial fibrillation (Afib). Results: Two hundred eighteen patients had cardioembolic, and 235 had non-cardioembolic stroke. Among patients with cardioembolic stroke, 49 (22.4%) and 142 (65%) had reduced EF and enlarged LA, respectively, as compared with 19 (8.1%) and 65 (27.7%) patients with non-cardioembolic stroke (p < 0.0001). The odds of cardioembolic stroke were 2.0 (95% CI: 0.1-6.0) and 8.8 times (95% CI: 1.9-42.3) higher in patients with moderately and severely reduced EF, respectively, than in patients with normal EF. The odds of cardioembolic stroke was 2.4 times (95% CI: 1.5-3.9) higher in patients with enlarged LA than in patients with normal LA size. Compared with patients with normal LA and EF, patients with combined enlarged LA and reduced EF had significantly higher rates of Afib (43.4 vs. 9.0%, p < 0.0001) and cardioembolic stroke (78.3 vs. 43.4%, p < 0.0001). Conclusions: LA dilatation along with reduced EF is a reliable predictor of Afib and cardioembolic stroke. Further studies are warranted to determine the benefit of anticoagulation for secondary stroke prevention in such patient population.