Figure 2.

Early mitral annular velocity (e′) and early transmitral filling velocity-to-mitral annular velocity ratio (E/e′) in SHRs and WKY rats. Data indicate differences in (a) septal e′ and (b) E/e′ with respect to strain and estrogen status (intact versus OVX). Values are reported as means ± SEM; SHRs, n = 6/group. WKY rats, n = 4–5/group. Black bars represent gonadal-intact rats; open bars represent OVX rats. Data were analyzed using two-way analysis of variance for strain and estrogen status (intact versus OVX) effects. Overall, SHRs had reduced ventricular lusitropy (e′) and higher filling pressures (E/e′) compared with WKY rats (strain effect on e′: F (1,17) = 17.14, p = 0.0008; and E/e′: F (1,17) = 5.24, p =0.035, respectively) *p < 0.05 and ***p < 0.001 indicate significance between strains. Even though estrogen loss reduced e′ and increased E/e′ in both strains (estrogen effect on e′: F (1,17) = 26.66, p < 0.0001; and E/e′: F (1,17) = 14.37, p = 0.002, respectively), the effects were most pronounced in the WKY rats, particularly e′ (interaction effect on e′: F (1,17) = 5.071, p = 0.039; and E/e′: F (1,17) = 1.622, not significant). Post-hoc analysis using Tukey’s multiple comparisons indicate significant differences only within the WKY strain for these diastolic functional parameters, with respect to estrogen status.

^#p < 0.05 and ^###p < 0.001.

OVX: ovariectomy; SEM: standard error of the mean; SHR: spontaneously hypertensive rat; WKY: Wistar-Kyoto rat.