Secondary R waves in leads V1or V3Rare definitely abnormal if the primiary R wave is high for the age group even though the R′ is small; if the secondary R wave is more than 6 mm.; or if the R′/S ratio exceeds 1. Other patterns may be found both in patients with heart disease and in normal subjects. In the abnormal cases, the QRS changes persist in leads taken below but in line with V1and V3R; but in normal cases, the secondary R waves usually disappear in the lower leads.