Left ventricular function in physiologic and pathologic hypertrophy in Sprague–Dawley rats

Abstract

Objective The aim of this study was to design a high intensity swimming training and two-kidney, one-clip (2K1C) hypertension protocol in Sprague–Dawley (SD) rats and to use current echocardiography techniques to examine the differential diagnosis between physiological and pathological left ventricular hypertrophy. Methods One group of SD rats performed swimming training at high intensive swimming training (HIGH) for eight weeks. In animals of the other arm of the study, a 2KIC hypertension was created and maintained for eight weeks. Results After eight weeks, all rats were studied by standard and tissue Doppler echocardiography. The heart weight/body weight ratio (HW/BW) of 2K1C and HIGH rats increased by 16% and 42%, respectively. Echocardiography showed increased septal and posterior wall thickness in both the 2K1C and HIGH rats. Left ventricular increased by 35 and 41% respectively. Left ventricular diameters, stroke volumes, cardiac output, and ejection fractions were unchanged in either group. Mitral inflow showed a decrease in late-wave velocity, thus increasing the E/A ratio in HIGH rats. However, mitral inflow showed an increase in late-wave velocity, thus decreasing the E/A ratio in 2K1C rats. There was a significant increase in Ea and early diastolic (Em)/late diastolic (Am) in HIGH rats in basal septum and lateral mitral valve annulus. And there was a significant increase in Am, which led to a significant decrease of Em/Am in 2K1C rats. No significant change occurred in pulmonary vein systolic velocity and diastolic velocity, in either of the three animal groups. However, there was significant increase in atrial reversal velocity in HIGH rats. Conclusions Doppler echocardiographic parameters of LV diastolic function can be of diagnostic importance for discrimination between pathologic and physiologic LV hypertrophy.