Corotto PS, et al. - Given that left atrial abnormality confers a significant risk for atrial fibrillation (AF) and stroke (both linked with obstructive sleep apnea [OSA]), and can be detected by electrocardiographic P-wave morphology, researchers investigated whether there is a link between OSA severity and more abnormal electrocardiographic P-wave morphology, as suggested by P-wave terminal force in V₁ (PTFV₁) and P-wave area in V₁ (PWAV₁). Overall, 261 patients (mean age 57 years old; 52% male) who had clinically indicated polysomnography and 12-lead ECG were found via medical record review. Adjusting for age, sex, body mass index, and hypertension, links between the measures of OSA severity (apnea hypopnea index [AHI] and mean nocturnal oxygen saturation) and abnormal PTFV₁ and PWAV₁ (defined by >75% percentile value of the studied cohort) were assessed using logistic regression. AHI was related to abnormal PTFV₁ and PWAV₁, as identified in multivariate analysis. Overall, a significant link between OSA severity and ECG-defined left atrial abnormality was found in this sleep clinic cohort.