Interventricular septal configuration as a predictor of right ventricular systolic hypertension in children: a cross-sectional echocardiographic study.

Abnormal interventricular septal position and motion have been noted in patients with right ventricular pressure overload. The quantitative relationship between this alteration in septal configuration and the severity of right ventricular systolic hypertension has not been previously reported. We used cross-sectional echocardiography to assess the radius of septal curvature at end-diastole, midsystole, and end-systole in 20 normal children and 29 children (ages 2 weeks to 20 years) undergoing cardiac catheterization for a variety of congenital cardiac disorders. The measured septal radius of curvature (r) was normalized by the ideal radius (ri) for the left ventricular cavity area and then expressed as normalized septal curvature [l/(r/ri)]. A slight leftward shift and flattening of the interventricular septum occurred in the course of normal systolic contraction (mean +/- SEM normalized curvature at end-diastole 0.92 +/- 0.03 and at end-systole 0.85 +/- 0.02; p less than .05). Marked exaggeration of this configurational change occurred in patients with right ventricular systolic hypertension (right ventricular systolic pressure greater than 50% systemic pressure), with progressive loss of curvature from end-diastole (0.45 +/- 0.05) to end-systole (0.19 +/- 0.06). Normalized septal curvature correlated well with relative right ventricular systolic pressure at all three sampling periods, with the best correlation at end-systole (r = .86). End-systolic flattening of the interventricular septum thus proved to be a sensitive marker for right ventricular systolic hypertension.