Usefulness of electrocardiographic parameters as compared with computed tomography measures of left atrial volume enlargement: From the ROMICAT trial

Introduction: The 12-lead surface electrocardiogram (ECG) is commonly used as a noninvasive modality to assess for left atrial enlargement (LAE), but data comparing ECG against cardiac computed tomography (CT) for LAE is lacking. We aimed to determine the diagnostic performance of 6 ECG criteria for LAE as compared with CT left atrial volume (LAV) and index to body surface area (LAVI) as the reference standard. Materials and Methods: In 339 patients (age: mean ± mean, 53 ± 12 years; 63% male), we evaluated the quantitative ECG parameters of P duration, P to PR segment ratio, P wave area, and P terminal force in lead V1. We also assessed qualitatively the morphology of bifid and biphasic P waves. Patients were stratified into top and lowest quartile of LAV and LAVI by CT. Results: Of the 6 ECG criteria, patients with P duration greater than 110 milliseconds had a 21/2-fold increase likelihood of being in the top quartile of LAV (adjusted odds ratio [OR], 2.51; P = .01) and LAVI (adjusted OR, 2.74; P = .007) as measured by CT. For this ECG criterion, the sensitivity and specificity were 71% and 55% for CT LAE by LAV and 61% and 55% for LAVI. The remaining ECG parameters of LAE assessed (P to PR segment ratio, P terminal force in lead V1, P wave area, bifid, and biphasic P wave) were not associated with LAE by CT-based LAV or LAVI (all P ≥ .20). Discussion: Only P duration greater than 110 milliseconds was independently associated with LAE based on CT-derived LA volume and index. However, none of the established ECG parameters of LAE have sufficient diagnostic accuracies for predicting volumetric enlargement by CT, thus limiting its clinical utility.