PubMed Health⌕ Search

Biomedical subjects

G de Simone

Publications and source records attributed to G de Simone.

At least 109 records · Page 6Linked to original sources
PubMed1992

In vivo left ventricular anatomy in rats with two-kidney, one clip and one-kidney, one clip renovascular hypertension.

OBJECTIVES: To evaluate differences in left ventricular structural changes related to different hemodynamic patterns. DESIGN: One-kidney, one clip (1K1C; volume-dependent hypertension) rats were two-kidney, one clip (2K1C; high-resistance hypertension) to determine whether these two types of Goldblatt rats showed different types of left ventricular adaptation. METHODS: M-mode echocardiography was used to study 28 2K1C and 19 1K1C Wistar rats 8 weeks after surgery and 55 age-matched control animals. RESULTS: Systolic blood pressure was equally high in the two models; the 1K1C rats had a larger left ventricular chamber and normal plasma renin activity (PRA), whereas in the 2K1C rats PRA was increased and the left ventricular chamber was normal. The atrial natriuretic factor was significantly increased only in the 2K1C rats and was related to PRA. The left ventricular mass index was increased in both models, but more in the 1K1C than the 2K1C rats. CONCLUSIONS: In both models the degree of left ventricular hypertrophy was associated with the interacting effects of the hemodynamic component superimposed on the primary hemodynamic pattern (i.e. blood pressure as an expression of pressure overload in the primarily volume-dependent 1K1C rats and the left ventricular chamber size as an expression of volume overload in the high-resistance 2K1C rats). The interaction between pressure and volume increased the left ventricular wall thickness in both models, with additional chamber enlargement in the 1K1C rats. In these rats, the increase in left ventricular mass was more pronounced due to the greater volume load on the heart.

Adaptation, Physiological↗
PubMed1991

Gender differences in left ventricular anatomy, blood viscosity and volume regulatory hormones in normal adults.

Gender differences in left ventricular (LV) anatomy, whole blood and plasma viscosity, and blood volume regulatory hormones were studied in 110 normotensive employed adults (28 black and 34 white men [mean age 51 +/- 12 years], 20 black and 28 white women [mean age 53 +/- 12 years]). LV mass and wall thicknesses were positively related to whole blood viscosity, primarily because of higher values of both variables in men. LV chamber size was inversely related to hematocrit and to blood viscosity (p less than 0.002) in women but not in men. Whole blood viscosity increased with age in men (p less than 0.01), but tended to decrease in women; older women also had better LV function, larger LV chambers, and a trend toward increasing LV mass. Atrial natriuretic factor increased with age in women but not in men (r = 0.60, p less than 0.001), and plasma renin activity decreased (r = -0.35, p less than 0.02). Thus, in women, increase in LV chamber size with age and associated changes in LV systolic function, atrial natriuretic factor levels and plasma renin activity suggest plasma volume expansion related to the aging process. These findings also suggest that an increase in LV volume load with age may contribute to previously reported increases in LV mass in older women.

Adolescent↗
PubMed1991

Echocardiographic left ventricular mass and electrolyte intake predict arterial hypertension.

OBJECTIVE: To identify predictors of arterial hypertension. PATIENTS: One hundred thirty-two normotensive adults from a large employed population. METHODS: Echocardiography, standard blood tests, and 24-hour urine collection, at baseline and after an interval of 3 to 6 years (mean, 4.7 +/- 0.8 years). RESULTS: At follow-up, 15 subjects (11%; 7 men, 8 women) had a systolic blood pressure greater than 140 mm Hg or a diastolic blood pressure greater than 90 mm Hg or both (mean, 143 +/- 7 and 87 +/- 6 mm Hg, respectively). At baseline, subjects who developed hypertension had a greater left ventricular mass index than those who did not (92 +/- 25 compared with 77 +/- 19 g/m2 body surface area; P less than 0.005) and higher 24-hour urinary sodium/potassium excretion ratio (3.6 +/- 1.7 compared with 2.6 +/- 1.4; P less than 0.04); there were no differences in race, initial age, systolic or diastolic blood pressure, coronary risk factors, or plasma renin activity. The likelihood of developing hypertension rose from 3% in the lowest quartile of sex-adjusted left ventricular mass index to 24% in the highest quartile (P less than 0.005); a parallel trend was less regular for quartiles of the sodium/potassium excretion ratio (P less than 0.04). In multivariate analyses, follow-up systolic pressures in all subjects and in the 117 who remained normotensive were predicted by initial age, systolic blood pressure, black race, and sex-adjusted left ventricular mass index; final diastolic blood pressure was predicted by its initial value, plasma triglyceride levels, urinary sodium/potassium ratio, low renin activity, black race, and plasma glucose level. CONCLUSIONS: Echocardiographic left ventricular mass in normotensive adults is directly related to the risk for developing subsequent hypertension. Left ventricular mass improves prediction of future systolic pressure, whereas diastolic pressure is more related to initial metabolic status. Black race is also an independent determinant of higher subsequent blood pressure.

Adolescent↗
PubMed1991

Left ventricular mass as a predictor of development of hypertension.

The mass of left ventricular (LV) muscle plays a central role in hypertension. Echocardiographic LV mass has been shown to reflect the level of blood pressure over time, obesity, diet, and other factors, and to serve as the strongest predictor yet discovered, other than advancing age, of cardiac complications of hypertension. Recent research suggests, in addition, that individuals destined to become hypertensive have increased LV mass before hypertension becomes clinically apparent. Several published studies have compared LV mass in groups of normotensive children to young adults considered to be at high or low genetic risk of hypertension based on the presence or absence of hypertension in their parents. In each instance LV mass was higher in the offspring of hypertensive parents and this difference exceeded that expected for small differences in body habitus or arterial pressure. A longitudinal study in children also showed that LV mass predicted subsequent blood pressure level. We recently performed a study of 132 initially normotensive employed adults, 15 (11%) of whom developed borderline hypertension during a 5-year follow-up. The development of hypertension was not predicted by subject age, body habitus, blood pressure, or a variety of biochemical measurements. The only baseline measurement that predicted development of hypertension was that of LV mass (92 +/- 25 v 77 +/- 19 g/m2, P less than .005), and the likelihood of developing hypertension increased progressively from 3% in the lowest quartile of LV mass of 24% in the highest quartile.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed1991

Slow-release isradipine in mild to moderate hypertension: hemodynamic and antihypertensive effects.

In this study we used casual and 24-h blood pressure (BP) monitoring and Doppler echocardiographic data to investigate the antihypertensive and hemodynamic effects of isradipine 5 mg in the new slow-release oral (SRO) formulation administered once daily for 12 weeks to 10 patients with mild to moderate hypertension. The antihypertensive action of SR isradipine was revealed by the normalized values of casual BP in 60 patients and by the significant reduction of 24-h BP variability as assessed by mean standard variation, coefficient of variation and the percent incidence of abnormal levels of both systolic and diastolic BP during 24 h (p less than .001). The echocardiographic data showed some beneficial hemodynamic effects (improvement of systolic and diastolic indices) without significant variation of left ventricular structure. The drug was well tolerated, with a low incidence of side effects. In conclusion, SR isradipine can be considered a safe and effective first-choice drug for the treatment of mild to moderate hypertension.

Administration, Oral↗
PubMed1990

The effects of nicardipine on sodium and calcium metabolism in hypertensive patients: a chronic study.

There is evidence in the literature that calcium entry blockers are able to affect calcium-dependent hormone secretion and therefore can influence sodium and calcium metabolism. We have studied in 18 mild to moderate hypertensives (27-65 yrs) the effects of chronic treatment with nicardipine, a dihydropyridine derivative, vs placebo on: 1) renin-angiotensin-aldosterone axis; 2) parathyroid hormone and calcium metabolism; 3) daily sodium and calcium urinary excretion. After a 2-week placebo wash-out when any antihypertensive treatment was withdrawn, patients were kept on a well balanced normocaloric diet without salt intake restriction. Blood pressure, plasma renin and serum aldosterone after a 1-hour standardized walk, serum PTH, serum and 24-hour urinary Na, K, Ca, P, Mg were measured. Thereafter patients were randomly and blindly given nicardipine 20 mg tid or placebo tablet tid for 2 months. At the end of this period the same measurements were repeated. Blood pressure significantly dropped during nicardipine (from 165/96 +/- 19/9 vs 150/88 +/- 16/9 mm Hg P less than .05) without change in heart rate. No change was observed on placebo. Plasma renin, serum aldosterone, serum parathyroid hormone and serum and urinary electrolytes did not change during active and placebo treatment. The results of this study suggest that chronic nicardipine does not affect hormone secretion.

Administration, Oral↗
PubMed1990

Echocardiographic measurement of left ventricular mass and volume in normotensive and hypertensive rats. Necropsy validation.

Although rats are commonly used to study left ventricular (LV) hypertrophy, measurement of LV mass and dimensions has required killing the rat. To determine the accuracy of echocardiography in rats, blinded crossectional area (CSA) and LV mass measurements using either the cube function (LVM) or an elliptical model (LVMel) from high resolution M-mode echocardiograms were compared to necropsy LV weight (0.28 to 1.5 g), in 41 normotensive (body weight 116 to 762 g) and 17 hypertensive rats (350 to 560 g). Postmortem chamber volumes in 28 normal rats (0.02 to 0.19 mL) were also compared to echocardiographic volumes derived from the elliptical model. Correlation with LV weight was r = 0.87 for LVM, 0.90 for CSA and 0.93 for LVMel (all P less than .00001). Comparison of hypertensive and body-weight-matched normotensive rats revealed the upper normal limit for both LVMel and CSA to have 89% sensitivity and 100% specificity for detection of post mortem LV hypertrophy. Necropsy LV volumes were more closely related to systolic echocardiographic volumes than to diastolic volumes (r = 0.78 v 0.71, both P less than .00001), compatible with the effects of post mortem contracture. Stroke volume determined invasively in 5 Wistar rats by thermodilution was similar to that obtained using elliptical model echo volumes in 5 rats of the same body size (0.35 +/- 0.05 v 0.30 +/- 0.06 mL/beat). Echocardiography can be used to evaluate LV structure and function in rats and to detect in vivo LV anatomic differences induced by hypertension.

Animals↗
PubMed1990

Relation of blood viscosity to demographic and physiologic variables and to cardiovascular risk factors in apparently normal adults.

Although increased blood viscosity occurs in several cardiovascular diseases, little is known of factors influencing blood rheology in normal adults. Accordingly, we examined the relations of whole blood viscosity (WBV) to its rheologic determinants (hematocrit level, plasma viscosity, protein concentration, and red cell aggregability and rigidity), to demographic and laboratory variables, and to cardiovascular risk factors in 128 normotensive employed adults. Hematocrit levels accounted for 67-84% of variability of WBV at shear rates from 208 to 0.1 sec-1 with lesser contributions from plasma viscosity, red cell aggregability, and rigidity (multiple r = 0.95-0.97); WBV was predicted accurately from standard measurements of hematocrit and total plasma protein levels (multiple r = 0.78-0.92 in "learning" and "test" analysis). Male sex, obesity, dietary Na+ intake, and increasing age had additive effects on WBV (multiple r greater than or equal to 0.59, p less than 0.00001); the last three of these factors and black race independently predicted plasma viscosity (multiple r = 0.36, p less than 0.001). Among regulators of plasma volume, plasma renin activity and urinary Na+ excretion bore independent positive relations to WBV. Diastolic and mean blood pressures were independent predictors of WBV and hematocrit levels (all p less than 0.05). Conventional risk factors (e.g., triglycerides, obesity, and cholesterol levels) were positively related to WBV or plasma viscosity. Thus, in apparently normal adults, 1) WBV or plasma viscosity are increased by male sex, obesity, high sodium intake, aging, and black race, 2) WBV is positively related to plasma renin activity, 3) WBV or plasma viscosity are related to diastolic and mean blood pressures, triglycerides and cholesterol concentrations, and 4) WBV can be predicted from simple measurements of hematocrit and total plasma protein levels.

Adult↗
PubMed1989

Effects of nicardipine on left ventricular hemodynamic patterns in systemic hypertension.

To assess left ventricular (LV) functional and structural changes associated with the reduction of blood pressure (BP) values during nicardipine administration (60 mg daily, for two months), 17 hypertensive patients were studied by M-mode echocardiography, according to a double-blind design (11 with nicardipine and six with placebo). Decrease in BP induced by nicardipine was associated with decrease in myocardial afterload (end-systolic stress) (P less than .002) and improvement of systolic function (fractional shortening) (P less than .02), without changes in inotropic state (assessed by systolic BP/end-systolic dimension/posterior wall thickness ratio). At the end of trial, a 5% reduction was found in LV mass (P less than .002), whereas relative wall thickness did not change. Diastolic phase (assessed by relaxation time index, and the slope of EF tract of the anterior mitral valve leaflet) was improved (.01 less than P less than .001). Patients with concentric and eccentric hypertrophy were separately considered. Relaxation time index and fractional shortening were significantly improved only in patients with concentric hypertrophy (P less than .01), whereas in the other ones the effect of treatment was variable. These differences were probably due to different effects on preload in the two LV hemodynamic patterns. Thus, nicardipine shows powerful effects on cardiac mechanics in systemic hypertension, but these effects are different according to LV anatomic pattern. Only in the presence of concentric hypertrophy is it possible to foresee the improvement of LV function; LV hypertrophy can be also reduced in concentric hypertrophy, but in the short term the reduction is too small to assume pathophysiologic significance.

Adult↗
PubMed1989

Adrenergic nervous system and left ventricular mass in primary hypertension.

A link between the activity of the adrenergic nervous system and left ventricular hypertrophy has frequently been found in hypertensives. In 16 patients with untreated primary hypertension of mild to moderate degree, we have evaluated the possible correlations between echocardiographic left ventricular mass (LVMe) and sympathetic nervous system activity, using pressor response to exogenous noradrenaline infusion, measurement of 24-h catecholamine urinary excretion and pressure response to ergometric exercise. Pressor response to noradrenaline infusion was significantly related to echocardiographic measures of left ventricular hypertrophy (correlation coefficients were: -0.60 for LVMe; -0.51 for septal thickness (ST); -0.51 for posterior wall thickness). Left ventricular mass was also related to systolic blood pressure measured during ergometric exercise (correlation coefficients were: 0.52 with LVM index, 0.51 with LVMe and 0.61 with ST). Arterial wall hypertrophy has been identified as being responsible for the vascular hyperreactivity in hypertension. A likely explanation of our findings is that the degree of left ventricular hypertrophy is associated with the degree of structural alterations of the resistance vessels and that the vascular impairment is responsible for the increased pressure response to noradrenaline.

Adult↗
PubMed1988

Supernormal contractility in primary hypertension without left ventricular hypertrophy.

Forty-three subjects with uncomplicated primary hypertension and without echocardiographic left ventricular hypertrophy and 54 normotensive volunteers were studied by two-dimensional targeted M-mode echocardiography to evaluate systolic function and contractility before the development of compensatory hypertrophy. The ratio of peak systolic pressure to end-systolic dimension was used to assess left ventricular performance and was divided for either posterior wall thickness or cross-sectional area to generate hypertrophy-independent indices of inotropic state. Fractional shortening was normal in the hypertensive group, despite the increase in end-systolic stress. Systolic pressure/dimension ratio was higher in hypertensive subjects (p less than 0.001), as were hypertrophy-independent indices of inotropic state (p less than 0.005), which were inversely correlated to left ventricular mass (p less than 0.001). Values in 11 hypertensive subjects were above the upper confidence limit of the normal shortening/stress relation, which provides a load-independent measure of inotropic state. They showed high hypertrophy-independent indices of inotropic state (p less than 0.01), while the other hypertensive subjects did not. High fractional shortening, wall stress, and systolic pressure (p less than 0.01) were found in the subgroup with supernormal performance, while left ventricular mass was not different from that of other subgroups, depicting inadequate left ventricular hypertrophy. The duration of hypertension was the same in the subgroups. Supernormal inotropic state could be considered one form of primary adaptation to high wall stress that serves to maintain systolic ventricular performance.

Adult↗
PubMed1988

Echocardiographic indexes of left ventricular contractility. Effect of load manipulation in arterial hypertension.

Load changes were obtained in 7 females with untreated primary hypertension by means of controlled intravenous infusion of sodium nitroprusside (0.2 mg/ml), in order to assess variations in the more usual indexes of left ventricular (LV) contractility to different loads and to verify that those indexes were independent of load. 2D-controlled M-mode echocardiograms were performed at baseline and when systolic blood pressure (SBP) had been reduced by 7, 16 and 23% for at least 5 min. Heart rate did not change during the test; decrease in SBP was associated with either decreases in both end-systolic dimension (LVIDs) and end-systolic stress (ESS), or an increase in systolic function. SBP/LVIDs, SBP/end-systolic volume (ESV) and ESS/LVIDs ratios were examined and compared as indexes of contractile state. SBP/ESV and ESS/LVIDs ratios showed great variation at all stages as compared to baseline values, while the SBP/LVIDs ratio did not change. The percent variation between the baseline values and the last stage of the test was 51% for the ESS/LVIDs ratio, 37% for the SBP/ESV and 5% for the SBP/LVIDs ratio. Best-fitting regression showed that a linear relationship existed only between SBP and LVIDs. Echocardiographic two-dimensional (as ESS) or three-dimensional derivations (as ESV) should be carefully employed when the contractile state is studied, while the SBP/LVIDs ratio can be easily used as a baseline value, as it is insensitive to changes in load.

Adult↗
PubMed1987

Hemodynamic hypertrophied left ventricular patterns in systemic hypertension.

The hemodynamic pattern of hypertrophied left ventricle in systemic hypertension was studied by M-mode echocardiography in 42 untreated hypertensive patients with left ventricular (LV) mass index greater than 2 standard deviations from the sex-specific mean of 114 normal subjects (normal values of our laboratory), and in 45 normotensive volunteers. Hypertensive patients showed cardiac dimensions, relative diastolic wall thickness, ratio of systolic pressure to end-systolic dimension, cardiac index and stroke index greater than normotensive control subjects (0.01 less than p less than 0.0001). Pressure/dimension ratio was correlated to relative wall thickness (p less than 0.005). End-systolic stress/volume ratio was normal as was systolic pressure to dimension ratio normalized for end-diastolic wall thickness. LV hypertrophy was concentric in 26% and eccentric in 74% of patients and suggested 2 different heart adaptations to overload: eccentric hypertrophy was associated with increased cardiac dimensions, high peak stress, normal systolic function and moderately increased LV contractility; concentric hypertrophy was associated with the highest blood pressure values, normal cardiac dimension, normal peak stress, normal systolic function and much increased LV contractility. Because stress/volume ratio and wall thickness-corrected systolic pressure/dimension ratio were normal in hypertensive patients, LV contractile capacity might be supported by the increase in myocardium available for contraction, rather than by increase in inotropic state.

Adult↗
PubMed1987

Indication for systemic-pulmonary artery shunts guided by two-dimensional and Doppler echocardiography: criteria for patient selection.

From June, 1983, to February, 1987, 91 patients with pulmonary outflow tract obstruction underwent a systemic-to-pulmonary artery shunt without an invasive study. The surgical indication was based on two-dimensional (2-D) and Doppler echocardiography only. In 82 patients (90.1%), 2-D and Doppler echocardiography allowed correct assessment of the intracardiac anatomy and of the morphology of the pulmonary arteries, pulmonary veins, and aortic arch. The aortic arch anatomy was misdiagnosed in 6 patients (6.6%) who underwent a modified instead of a classic Blalock-Taussig shunt. In 3 patients (3.3%), the indication for the systemic-pulmonary artery shunt was inappropriate; in 1, operative death resulted from the incomplete diagnosis. After the preselection of patients based on knowledge of the anatomical patterns, a systemic-pulmonary artery shunt may be performed without cardiac catheterization if these rules for definitive patient selection are followed: (1) accurate clinical assessment to identify the patients with restricted pulmonary blood flow; (2) precise intracardiac diagnosis by 2-D and Doppler echocardiography; and (3) definitive 2-D echocardiographic visualization of the pulmonary venous connection and the confluence of the pulmonary arteries.

Anastomosis, Surgical↗
PubMed1987

Left ventricular mass and blood pressure during ergometric exercise in primary hypertension.

The pathophysiology of left ventricular hypertrophy (LVH) in hypertensive patients is still an intriguing point. The lack of a close relationship between LVH and systolic or diastolic blood pressure at rest, previously observed by other investigators, was confirmed in our group of 45 patients with uncomplicated primary hypertension. The strength of correlation between echocardiographic left ventricular mass (LVMe) and blood pressure, expressed as incremental area (IA = total area under the curve--basal area), however, increased during bicycle exercise testing (r = 0.33, p less than 0.05 for diastolic blood pressure; r = 0.39, p less than 0.01 for systolic blood pressure; r = 0.41, p less than 0.01 for mean arterial pressure). Other echocardiographic parameters of myocardial mass such as LVM index (LVMI) and septal thickness (ST) were also significantly correlated with blood pressure during exercise. These results suggest either that blood pressure during exercise is a better index of the cardiac workload than resting blood pressure or that the pathogenesis of cardiac hypertrophy involves an enhanced reactivity to adrenergic drive, particularly stimulated during ergometric exercise. Increased blood pressure alone, however, only partly accounts (about 20%) for the increase in myocardial mass in hypertensive patients; other factors, therefore, need to be further investigated for a better understanding of the pathophysiology of left ventricular hypertrophy.

Adult↗