The Significance of Crochetage on the R wave of an Electrocardiogram for the Early Diagnosis of Pediatric Secundum Atrial Septal Defect.

The purpose of this study was to test the hypothesis that the incidence of crochetage on the R wave in inferior limb leads can be used for the diagnosis of pediatric secundum atrial septal defect (ASD). Two hundred fifty-six children with secundum ASD (case cohort) and 256 age- and gender-matched children without heart disease (control cohort) were included in the study. Statistical analyses were performed to test the relationship between the ASD and the crochetage on the R wave with a single lead and three leads, respectively. The impact of incomplete right bundle branch block (IRBBB) and ASD diameter (≥ 5 and < 5 mm) on ASD diagnosis were also explored. Crochetage on the R wave was observed in all three inferior limb leads on 28.13% (72/256, 28 with IRBBB) of subjects with secundum ASD, while it was seen in only 2.73% (7/256, one with IRBBB) of control subjects (P < 0.001). Subgroup analysis showed that the incidence of R wave crochetage correlated with ASD size in both the single inferior limb lead (26.14%, 23/88 on ASD ≥ 5 mm vs. 10.71%, 18/168 on ASD < 5 mm; P = 0.001) and all three inferior limb leads (44.32%, 39/88 on ASD ≥ 5 mm vs. 19.64%, 33/168 on ASD < 5 mm; P < 0.001). Our findings suggest that crochetage on the R wave in inferior limb leads can serve as an independent marker for ASD diagnosis.