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Aim of recent experimental and clinical studies has been to evaluate the important role of the renin-angiotensin system in the development of cardiac hypertrophy, of vascular hypertrophy and of left ventricular fibrosis and remodelling in essential hypertension and ischemic heart disease. It has been suggested that ACE-inhibitors are the class of antihypertensive drugs more effective in reducing left ventricular hypertrophy (LVH) in hypertensive patients. The possible mechanisms are, beyond the decrease in blood pressure, the possibility of interfering not only with the renin-angiotensin system activity, but also with the sympathetic nervous system activity as well as with aortic distensibility, all factors that can influence the development of LVH. Vascular changes in essential hypertension are complex and depend not only on the severity of blood pressure levels, but are related to diameter and structure of the vessels and to the presence of other atherosclerosis risk factors. ACE-inhibitors are effective in inducing the regression of structural changes in resistance arterioles and furthermore can increase arterial compliance in large arteries; new studies are undergoing in order to assess the effects of these drugs on atherosclerotic plaque progression/regression. The results of large clinical trials have shown the efficacy of ACE-inhibitors in the treatment of heart failure, in addition, after it has been demonstrated that ACE-inhibitors can influence the structural remodelling process after myocardial infarction, their use has been extended to patients with ischaemic heart disease.

The involvement of cardiopulmonary and arterial sinoaortic receptors in the control of antidiuretic hormone (ADH) and atrial natriuretic peptide (ANP) release is still controversial in humans. Moreover, it is not clear if this control may be impaired in hypertensive patients with left ventricular hypertrophy (LVH). We studied 17 male subjects, age 18-58 (6 normotensives and 9 mild hypertensives, 5 without and 4 with LVH). Each subject underwent selective loading and unloading of cardiopulmonary receptors, in a randomized sequence, by application of a positive (LBPP) or negative (LENP) pressure to the lower body (steps: +10, +20, +40, -10, -40 mmHg, each for about 30 min), through a plexyglass-constructed tubular apparatus with a rubber adhesion round the patients' waist. Blood samples were taken at the end of every step for measurement of ADH, ANP, PRA, immunoreactive renin, aldosterone, noradrenaline and adrenaline. Cuff arterial pressure was measured every 5 min, while heart rate was evaluated by continuous ECG recording. Hypertensive subjects underwent right atrial pressure measurement by an iv catheter and forearm blood flow evaluation at rest and during the different steps (venous occlusion plethysmography). During LBNP, ADH plasma levels increased progressively, but the increase became statistically significant only at the step of -40 mmHg. ANP increased significantly during LBPP. Taking into account only hypertensive patients, a consistent reduction in the changes of ADH and ANP plasma levels, respectively during LBNP and LBPP in patients with LVH in respect to those without LVH was found.(ABSTRACT TRUNCATED AT 250 WORDS)