Widened E point septal separation in a normal pediatric population.

To determine the age and gender distribution of the E point septal separation (EPSS), M-mode echocardiograms were obtained from 121 normal subjects aged four months to 82 years. A small but consistent age factor was found. In subjects less than age 20, EPSS was 3.0 +/- 2.6 mm, whereas in those greater than 20 years, EPSS was 1.4 +/- 1.8 (p less than .001). In females EPSS did not vary appreciably at different ages. By contrast, in males EPSS increased with age, peaking between ages 15 and 19 and then decreasing. Between ages 10 and 19, EPSS was significantly wide in males than in females. Thus, EPSS is wide in male adolescents than in adults. The cause for this phenomenon is unclear, but judging from its age and gender distribution, it may be related to the effect of androgens on the myocardium.