Case 11: Low Atrial Rhythm in a 9-Year-Old Girl

During a clinical evaluation for sports participation, a 9-year-old girl was found to have negative P waves on her electrocardiogram (ECG) (Figs. 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 17.10, 17.11, and 17.12). She practiced handball, participating in five training sessions a week and a match on the weekends. Echocardiography ruled out any cardiac abnormality. No presence of atrial septal defect or persistence of left superior vena cava was seen. Her electrocardiograms exhibited low atrial rhythm alternating with normal sinus rhythm (Figs. 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 17.10, 17.11, and 17.12).