6 Accuracy of Electrocardiography and Agreement with Echocardiography in the Diagnosis of Left Atrial Enlargement in Pediatric Patients: A Case-Control Study

Abstract

Left atrial enlargement (LAE) has been established as a marker for diastolic dysfunction in left-sided cardiac disease. The gold-standard for diagnosis is the echocardiogram. In clinical practice pediatric patients who are suspicious for LAE often receive echocardiograms with concurrent electrocardiograms (ECGs) to exclude other diagnoses. Given the wider access and lower economic cost of ECGs compared to echocardiograms, ECGs have great potential to be used as a screening test to identify patients who would benefit from further investigation by echocardiography. However, the use of ECG criteria for the diagnosis of LAE has not been validated in the pediatric population. To identify the diagnostic utility of independent or combinations of ECG criteria to diagnose LAE in the pediatric population. A large retrospective case-control study (n=492) was conducted at a pediatric hospital in patients identified by echocardiography as meeting ≥1 of the following LAE criteria: 1) left atrial indexed diameter z-score ≥2.0, or 2) increased left atrial to aortic root ratio at various cutoffs (≥1.4, ≥1.6, ≥1.8). ECG criteria included: 1) a P wave ≥110 msec, 2) P mitrale ≥40 msec, and 3) a terminal negative portion of P wave in lead V1 >40 msec, 4) P/PR segment >1.4, 1.6, or 1.8 in lead II. Sensitivity, specificity, Cohen’s Kappa coefficient (κ), and receiver operating characteristic curves (ROC) were constructed to investigate the diagnostic utility of single and combination criteria. Diagnostic performance of ECG criteria had low to moderate sensitivity (20.8–55.0%) and moderate to high specificity (73.6–96.1%). The greatest agreement occurred when using two ECG criteria: P mitrale ≥40 msec and a terminal negative portion of the P wave in lead V1 >40 msec (κ = 0.221, 95% CI 0.060–0.382). ROC curve analysis further demonstrated that terminal negative P wave in V1 is the most strongly correlated with the echocardiographic criteria (AUC:0.580–0.581). The presence of positive ECG criteria indicates a probable diagnosis of LAE, however the absence of ECG criteria cannot be used to exclude this diagnosis. It should be noted that the presence of these criteria should not be used in isolation. Further research is required to determine correlation with clinical presentation and implications for clinical management.