The influence of antihypertensive treatment on left ventricular compliance and myocardial stiffness

Abstract

To investigate whether an antihypertensive treatment with a vasodilatator and a betareceptor-blocker will affect left ventricular (LV) compliance (△V/AP) and myocardial stiffness, 4-week-old spontaneously hypertensive rats (SHR) were treated with hydralazine only (H) and with hydralazine and metoprolol (M+H) combined and compared with equally aged untreated ones. LV compliance and stiffness data were obtained by means of a passive pressure-volume relationship of the diastolically arrested left ventricle. An inverse relationship was found between LV hypertrophy, which was quantified by the LV muscle mass divided by the LV end-diastolic volume, i.e., mass-volume ratio, and LV compliance (AV/AP). After treatment with hydralazine and metoprolol, LV mass-volume ratio was considerably reduced (H: −21.8%; M+H: −38.5%), and LV compliance (H: +61.4%; M+H: + 111 %) enhanced in comparison to the untreated controls. Myocardial stiffness and LV collagen concentration were not different between treated and untreated animals.