The Accuracy of Combined Electrocardiogram Criteria to Diagnose Right Atrial Enlargement in Adults With Uncorrected Secundum Atrial Septal Defect

Background: Right atrium (RA) enlargement in uncorrected atrial septal defect (ASD) is due to chronic volume overload. Several electrocardiogram (ECG) criteria had been proposed for screening RA enlargement. This study aimed to compare the accuracy of ECG criteria in detecting RA enlargement in adults with uncorrected ASD. Methods: This was a cross-sectional study involving 120 adults with uncorrected secundum ASD. The subjects underwent ECG examination, transthoracic echocardiography, and right heart catheterization. An RA enlargement was determined with RA volume index by transthoracic echocardiography. Various ECG and combined ECG criteria were evaluated. Statistical analysis was performed to analyze the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV). Results: An RA enlargement was detected in 64.2% subjects. The P wave height > 2.5 mm in lead II criterion had the best specificity (100%) and PPV (100%), but low sensitivity (19%) and accuracy (48%). The combined 2 ECG criteria (QRS axis > 90°, R/S ratio > 1 in V1) had 82% sensitivity, 56% specificity, 73% accuracy, 77% PPV, and 63% NPV. The combined 3 ECG criteria (QRS axis > 90°, R/S ratio > 1 in V1, and P wave height > 1.5 mm in V2) had 35% sensitivity, 86% specificity, 53% accuracy, 82% PPV, and 43% NPV. Conclusions: The combined 2 ECG criteria (QRS axis > 90° and R/S ratio > 1 in V1) had increased sensitivity, better accuracy, and more balance of PPV and NPV as compared with P wave > 2.5 mm in II criterion and combined 3 ECG criteria to diagnose RA enlargement in adults with uncorrected ASD.