Echo Doppler assessment of left ventricular function in rats with hypertensive hypertrophy

Objective: This study attempted to establish echocardiographic measurements of left ventricular (LV) mass and LV systolic and diastolic function, particularly in rats with hypertensive heart. Methods: M-mode LV echograms and Doppler mitral flow were obtained in Dahl salt-sensitive rats placed on 0.3% or 8% sodium chloride diet. Echo Doppler measurements were compared with catheterization and pathologic measurements in 54 rats for LV mass and in 45 rats for LV systolic and diastolic function. Results: Echocardiographic measurement of LV mass correlated well with pathologic measurement (r = 0.94, P < .01, n = 54, SEE = 0.08 mg), independent of LV size, aging, and therapeutic intervention. Endocardial fractional shortening (FS) correlated with LV peak + dP/dt (r = 0.56, n = 45, P < .01), and the correlation was improved to r = 0.71 if 11 rats with marked LV hypertrophy were excluded. Midwall FS correlated well with LV peak + dP/dt (r = 0.72, n = 45, P < .01) even if rats with extremely thickened ventricular wall were included. If midwall FS was lower than 14%, LV systolic dysfunction was very likely (sensitivity 67%, specificity 91%). Association of mitral E/A ratio of 2.0 or greater with deceleration time of shorter than 35 ms was an accurate indicator of elevated LV end-diastolic pressure (sensitivity 82%, specificity 86%) and increased lung weight because of congestive heart failure (sensitivity 89%, specificity 96%) in rats with hypertension. Conclusion: LV mass, LV systolic function, and LV end-diastolic pressure were assessable with echo Doppler in rats with hypertensive heart.