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.
Keywords: Crochetage on R wave; Inferior leads; Pediatric; Secundum atrial septal defect.