Notching of the QRS complex in high frequency electrocardiograms of normal children and in children with rheumatic fever

The high frequency components of the electrocardiogram in children have been recorded and analyzed with the high frequency response down three db at 10,000 Hz. Both the standard chest and the McFee-Parungao orthogonal lead systems (X and Z) were used. There were three groups studied, including 79 normal children, 24 with previous rheumatic fever, and two children with active rheumatic fever. Conclusions reached were:o1.In normal children, notching was more common in the standard right chest leads than the left chest leads.2.Notching may be present in one precordial lead and be absent in both adjacent precordial leads.3.Notching is more common in lead Z than lead X.4.Notching may be present in a precordial lead and be absent in the corresponding orthogonal lead. The reverse was less common.5.Five of 24 with previous rheumatic fever had increased notching.6.Both children with active rheumatic fever had increased notching.