Correlation of left ventricular hypertrophy and its regression by lisinopril with salt-induced hypertension

The interaction of salt with hypertension-induced left ventricular hypertrophy and its reversal by inhibition of angiotensin converting enzyme were studied in salt sensitive and salt resistant Dahl rats. Eight-week-old rats were fed either a low or high salt diet for three weeks. The colonies were then further divided and either treated with lisinopril or given no treatment for 11 weeks. Untreated salt sensitive rats had higher blood pressures than salt resistant animals. Left ventricular weight and wall thickness in both untreated salt sensitive groups was higher than in the resistant groups. Therapy lowered blood pressures in all groups but those of the high salt group remained higher than the low salt group. Reduction of left ventricular weight and wall thickness took place in either strain only when salt intake was low. Right ventricular and atrial weights were largely unaffected either by salt intake or drug therapy. Plasma renin activity increased and aldosterone levels decreased with lisinopril therapy in all groups except the salt sensitive, high salt group where both remained unchanged at low levels. Lisinopril was effective in reducing blood pressure and left ventricular hypertrophy, but both effects were severely impaired by high salt intake. The major determinant of left ventricular hypertrophy appeared to be afterload, as shown by a good correlation between left ventricular mass and systolic blood pressure, but there was some indication of a possible independent hypertrophic action of salt.(ABSTRACT TRUNCATED AT 250 WORDS)