Figure 1.

A) The increase in heart and body weight slows somewhat near birth (n = 114). B) LV and RV free wall weights are similar in fetal sheep. After birth both free walls continue to increase in weight, but the LV does so more rapidly than the RV (combined n = 39; P = 0.0075). C) The ratio of each free wall to total heart weight diverged rapidly at birth (n = 39). Regression (solid) lines and 95% CI (dashed) best fit to each data set are shown; bars show the 95% CI of the breakpoint. Fetal data from Jonker et al. (3). Regression data are included in the text and Tables 1 and 2.