The effect of
hydrochlorothiazide (1 mg/kg per day) on left ventricular (LV) mass and systolic and diastolic function was investigated in two-kidney, one
clip (2K1C) renovascular hypertensive rats.
Hydrochlorothiazide was administered from 8 weeks, and LV mass and function were measured at 16 weeks after surgery to induce
hypertension. Cardiac performance was determined from cardiac output, stroke volume (per 100 g of
body weight), and
stroke work (per gram of LV weight) versus LV end-diastolic pressure (LVEDP) and versus LV strain relations in anesthetized open-chest, ventilated rats. LV compliance was determined from the LVEDP versus strain relation. Strain was calculated from LV end-diastolic short-axis diameter values.
Hydrochlorothiazide reduced systolic blood pressure in 2K1C rats to levels similar to those in
sham-operated controls (
sham) at 12 weeks after surgery. A reduced afterload failed to influence LV mass, as left LV
hypertrophy developed to the same extent in treated 2K1C rats. 2K1C
hypertension produced abnormal cardiac performance with altered cardiac output, stroke volume, and
stroke work versus LVEDP relations (
stroke work versus LVEDP, intercept of 2K1C versus
sham, p < 0.001). This was attributed to a decreased ventricular compliance (strain versus LVEDP, slope of 2K1C versus
sham, p < 0.001). In contrast,
hydrochlorothiazide improved ventricular compliance (strain versus LVEDP, slope of 2K1C versus 2K1C
hydrochlorothiazide, p < 0.01) and thus returned the
stroke work versus LVEDP relation to
sham values (intercept of 2K1C versus 2K1C
hydrochlorothiazide, p < 0.001). We conclude that
hydrochlorothiazide reduces blood pressure but not the development of ventricular
hypertrophy in 2K1C rats.(ABSTRACT TRUNCATED AT 250 WORDS)