Figure 3.

SU5416-hypoxia (SuHx) rats develop right ventricular (RV) pressure and volume overload. Representative short axis images at end-diastole (ED; A) and end-systole (ES; B) demonstrate the normal circular appearance of the left-ventricle (LV) in a healthy, normoxic control (CTRL) rat. In contrast, volume and pressure overload of the RV in SuHx rats results in flattening of the intraventricular septum at ED (C) and ES (D). SuHx rats had significant increases in the mean ED (E) and ES (F) eccentricity index compared with CTRL rats. However, there were no significant differences in the ED or ES eccentricity indices between the three groups prior treatment (P ≥ 0.52 for each of the post hoc pairwise comparisons). The eccentricity index refers to the ratio of the LV minor-axis diameter parallel to the septum (D₂) divided by the LV minor-axis diameter perpendicular to the septum (D₁). Data are presented as means ± SD of 4 normoxic CTRLs and 13–15 animals per treatment group. One-way ANOVA was used to compare the four groups followed by post hoc Tukey’s test for pairwise contrasts. ***P < 0.001, ****P < 0.0001. EPL, eplerenone; PL, placebo; SPL, spironolactone.