Background and aims: Left ventricular hypertrophy (LVH), assessed by electrocardiogram (ECG), is associated with increased risk for stroke. However, few studies that evaluated whether ECG-detected LVH predicts ischemic stroke severity and outcome. We aimed to evaluate these associations. Methods: We prospectively studied 922 patients consecutively admitted with acute ischemic stroke (age 79.6 +/- 6.9 years). Stroke severity was assessed at admission with the National Institutes of Health Stroke Scale (NIHSS). Severe stroke was defined as NIHSS >= 5. LVH was evaluated with the Sokolow-Lyon index and the Cornell voltage-duration product criteria in an ECG obtained at admission. The outcome was assessed with dependency at discharge (modified Rankin scale 2-5) and in-hospital mortality. Results: Independent predictors of severe stroke were age (relative risk (RR) per year 1.07, 95% confidence interval (CI) 1.03-1.11, p< 0.001), female gender (RR 0.36, 95% CI 0.17-0.76, p< 0.01), atrial fibrillation (RR 2.07, 95% CI 1.30-3.29, p< 0.005), chronic kidney disease (RR 2.38, 95% CI 1.04-5.44, p< 0.05), heart rate (RR per 1/min 1.02, 95% CI 1.01-1.04, p< 0.005), glucose levels (RR 1.012, 95% CI 1.006-1.018, p< 0.001), high-density lipoprotein cholesterol levels (RR 0.976, 95% CI 0.960-0.993, p< 0.005) and LVH defined according to the Cornell voltage-duration product criteria (RR 2.08, 95% CI 1.12-3.86, p< 0.05). Independent predictors of dependency at discharge were age (RR per year 1.08, 95% CI 1.03-1.13, p< 0.001), past smoking (RR versus no smoking 0.42, 95% 0.19-0.89, p< 0.05), history of ischemic stroke (RR 2.13, 95% CI 1.23-3.71, p< 0.01) and NIHSS at admission (RR 1.48, 95% CI 1.35-1.63, p< 0.001). Independent predictors of in-hospital mortality were glucose levels (RR 1.014, 95% CI 1.003-1.025, p< 0.05), NIHSS at admission (RR 1.29, 95% CI 1.19-1.41, p< 0.001) and LVH according to the Cornell voltageduration product criteria (RR 4.95, 95% CI 1.09-22.37, p< 0.05). Conclusions: LVH according to the Cornell voltage-duration product criteria appears to be associated with more severe stroke and with higher in-hospital mortality in patients with acute ischemic stroke. (C) 2018 Elsevier B.V. All rights reserved.