Heart size on chest X-ray as a predictor of cardiac enlargement by echocardiography in children

To determine the usefulness of heart size on chest radiograph (CXR) in pred icting cardiac enlargement (CE) in children, we prospectively evaluated 95 consecutive outpatients, who had both a CXR and echocardiography performed. Their median age was 5.0 years (2 days to 19.9 years). All patients underw ent CXR assessment by a pediatric radiologist, with classification of cardi ac silhouette as normal, borderline, or enlarged. Echocardiographic assessm ent of CE was performed by a pediatric echocardiographer. Sensitivity, spec ificity, and predictive values of the pediatric radiologist's interpretatio n of heart size on CXR were estimated. The presence of CE by echocardiograp hy was used as the gold standard. Seventy-nine patients (83.2%) had no CE o n CXR, and 16 patients ( 16.8%) had CE. Sensitivity of the CXR to identify CE was 58.8%, 95% confidence interval (CI) [32.9, 81.6], with a positive pr edictive value of 62.5% [35.4, 84.8]. Specificity was 92.3% [84.0, 97.1], w ith a negative predictive value of 91.1% [82.6, 96.4]. These data suggest t hat the assessment of CE on CXR to predict CE by echocardiography has a rel atively high specificity and negative predictive value, but a low sensitivi ty and positive predictive value. The limitations of CXR as a diagnostic te st should be understood by clinicians using the test when screening childre n for cardiac disease.