Objectives: To test the sensitivity and specificity of the crochetage pattern (a notch near the apex of the R wave in electrocardiographic inferior limb leads) in the pediatric electrocardiogram for detecting patients with a secundum atrial septal defect.
Patients and methods: Electrocardiograms from 82 consecutive preoperative pediatric patients with a secundum atrial septal defect confirmed by two-dimensional echocardiography were reviewed for evidence of right ventricular hypertrophy and the crochetage pattern. These electrocardiograms were compared with 244 consecutive preoperative controls consisting of patients with echocardiographically proven patent foramen ovale, ventricular septal defect, pulmonary stenosis, tetralogy of Fallot and patients with normal echocardiogram studies.
Results: The electrocardiographic crochetage pattern was observed in 31.7% of preoperative patients with a secundum atrial septal defect in at least one inferior limb lead. The specificity of the crochetage pattern for the detection of a secundum atrial septal defect was high when present in all three inferior limb leads (greater than 92%). The crochetage pattern in at least one lead in secundum atrial septal defects shows no association with incomplete right bundle branch block (c2(1)=0.80, not significant), and thus these two findings together do not improve the detection of an atrial septal defect.
Conclusions: The sensitivity and specificity of the electrocardiographic crochetage patterns in at least one inferior limb lead in echocardiographically proven secundum atrial septal defects are 31.7% and 86.1%, respectively. The electrocardiographic crochetage or notching pattern in inferior limb leads has a high specificity for atrial septal defects in the pediatric population.