Spontaneous hypertension in rats was associated with early and progressive impairment in ventricular relaxation and altered left ventricular compliance with aging compared to normotensive rats.
Observational
How do hypertension and aging affect long-term left ventricular function and structure in spontaneously hypertensive rats compared to normotensive rats?
Long-term echocardiographic follow-up demonstrates that pressure-related changes, specifically impaired relaxation and compliance, are the dominant features of left ventricular dysfunction in aging spontaneously hypertensive rats.
Long-term follow-up of left ventricular (LV) function using echocardiography has not been reported and, in this study, was carried out in normotensive (WKY) rats and spontaneously hypertensive rats (SHR). In 10 WKY rats and SHR, LV diastolic and systolic diameter (LVEDD and LVSD), shortening fraction (SF), and weight (LVW) were determined at 8, 15, 20, 35, and 80 wk of age. The ratio of early to late mitral flow and mitral annulus velocity (VE/VA and Em/Am), isovolumic relaxation time (IVRT), deceleration time of the E wave (DTE), Tei index, and mitral flow propagation velocity (Vp) were measured. No difference in LVEDD was found between SHR and WKY rats; however, LVEDD was increased at 80 wk in both strains. SF decreased slightly in old WKY rats. LVW progressively increased from 20 to 80 wk in both strains and was greater in SHR. VE/VA and Em/Am decreased at 80 wk in WKY rats. LV relaxation (IVRT, Tei index, and Vp) was progressively impaired in SHR compared with WKY rats. LV compliance (DTE) was altered in old SHR. Echocardiography permitted a long follow-up of LV function in SHR and WKY rats. Ventricular relaxation was impaired early in the life of SHR and progressed with aging. Furthermore, LV compliance was altered, but systolic function remained unchanged, in old SHR. In contrast, relaxation and SF were only slightly altered in old WKY rats, suggesting that pressure-related changes in LV function were the dominant features in the SHR.
Slama et al. (Thu,) conducted a observational in Hypertension. Spontaneous hypertension vs. Normotensive (WKY) rats was evaluated on Left ventricular function and structure. Spontaneous hypertension in rats was associated with early and progressive impairment in ventricular relaxation and altered left ventricular compliance with aging compared to normotensive rats.