Truong QA， Charipar EM， Ptaszek LM， Taylor C， Fontes JD， Kriegel M， Irlbeck T， Mahabadi AA， Blankstein R， Hoffmann U.
Cardiac MR PET CT Program， Department of Radiology， Massachusetts General Hospital， Harvard Medical School， Boston， MA， USA; Division of Cardiology， Massachusetts General Hospital， Harvard Medical School， Boston， MA， USA.
Abstract
    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 2(1/2)-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.