ECG and CT for the detection of left atrial enlargement in hypertensive individuals-a population-based study

Left atrial enlargement (LAE) is associated with hypertension and an increased risk of cardiovascular morbidity and mortality. Guidelines for hypertension recommend LAE evaluation. We aimed to estimate the agreement of LAE as assessed by 12-lead electrocardiogram (ECG) and cardiac computed tomography (CT) in both the general population and hypertensive individuals. Cardiac CT and ECG were used to evaluate the presence of LAE in participants in the Copenhagen General Population Study. LAE, is defined as an LA volume above the 97.5% upper confidence limit by cardiac CT, as compared with multiple ECG criteria for LAE. A total of 3507 participants (47% males, age: 60 ± 10 years) were included. The prevalence of CT-defined LAE was 5.9% in the total population and 8.7% in participants with hypertension. In hypertensive individuals, LAE was identified by CT or by ECG in 31% with only a 4% overlap. ECG signs for anatomical LAE by CT had high negative predictive values between 93 and 96% but low sensitivity and positive predictive values. Specificity ranged from 27 to 93%. P-wave duration >120 ms was the best performing criterion, with a sensitivity of 48%, a specificity of 78%, and the highest area under the curve (0.66). We found a discrepancy in LAE prevalence when participants were assessed by CT and ECG, indicating that the two diagnostic modalities reflect different phenotypes of left atrial alterations. The diagnostic performance of ECG criteria for identifying anatomical LAE was poor.