Electrocardiographic P-wave amplitude as a discriminative marker for pediatric atrial septal defects

BACKGROUND: Atrial septal defects (ASD) are often asymptomatic during childhood, resulting in a delayed diagnosis. Electrocardiography (ECG) screening is known to have a limited ability to detect ASD, relying mainly on QRS abnormalities, such as incomplete right bundle branch block (IRBBB). In contrast, P waves have been underused because they are small, often on a trended baseline, and thus difficult to quantify accurately. This observational study examined the utility of baseline-corrected P-wave amplitude in the identification of ASD. METHODS: We analyzed digital ECG data from 45 secundum ASD patients 4-9 years old and 94 matched controls without structural heart defects. Using a semi-automated algorithm, we precisely measured the P-wave amplitude following rigorous baseline correction. We conducted a receiver operating characteristic (ROC) curve analysis to differentiate ASD patients from controls. RESULTS: The overall performance of the P-wave amplitude in lead V3 was high, with an area under the ROC curve (AUROC) of 0.883. When the analysis was limited to patients with defect sizes of ≥5 mm, the V3 amplitude had an excellent AUROC (0.954) with 83.3% sensitivity and 95.7% specificity, outperforming conventional ECG findings, including IRBBB. This significance was supported by a good correlation between the V3 amplitude and the right atrial size quantified by echocardiography. CONCLUSIONS: The present study demonstrates the potential utility of accurately measured P-wave amplitude for the detection of hemodynamically significant pediatric ASD. Further investigations, including external validation in diverse clinical settings and the development of a fully automated analytic algorithm, are required before clinical implementation.