Left ventricular hypertrophy in hypertensive patients

Hydrochlorothiazide improves ventricular compliance and thus performance without reducing hypertrophy in renal artery stenosis in rats

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)

Relation of left ventricular mass, preload, afterload and contractility in pediatric patients with essential hypertension

OBJECTIVES

The aim of this study was to determine if left ventricular preload, afterload or contractility is a correlate of left ventricular mass index in hypertensive pediatric patients.

BACKGROUND

It is believed that decreased contractility and increased preload are associated with left ventricular hypertrophy in adult hypertensive patients.

METHODS

Ninety pediatric hypertensive patients underwent echocardiography to assess left ventricular mass, preload (diastolic dimension and volume) and afterload (end-systolic wall stress, vascular resistance and blood pressure). Contractility was assessed by 1) the end-systolic stress/volume ratio, and 2) the difference between measured and predicted velocity of circumferential fiber shortening. Univariate and multivariate analyses were performed.

RESULTS

Univariate analysis showed significant correlations between left ventricular mass and 1) body mass (r = 0.33, p < 0.001), 2) black race (r = 0.37, p < 0.0003), 3) diastolic dimension (r = 0.26, p < 0.01), 4) diastolic volume (r = 0.20, p < 0.05), and 5) stress/volume ratio (r = -0.53, p < 0.0001) but not the difference between measured and predicted velocity of circumferential fiber shortening. A multivariate model included body mass, age at diagnosis, diastolic dimension, wall stress and vascular resistance but not the difference between measured and predicted velocity of circumferential fiber shortening.

CONCLUSIONS

Contractility is not significantly related to left ventricular mass. The positive correlation between mass and stress/volume may be due to the dependence of the latter variable on loading conditions. We speculate that both elevated preload and systemic vascular resistance may have a role in the development of hypertrophy in hypertensive pediatric patients.

Antihypertensive therapy in the geriatric patient: II. A review of the alpha1-adrenergic blocking agents

The prevalence of hypertension increases with age. Multiple physiologic factors are involved in the development of hypertension in the elderly. Alpha1-adrenergic blocking agents lower blood pressure through a reduction in total peripheral resistance. Prazosin, terazosin, and doxazosin have been shown to be equally effective in reducing blood pressure in older persons. The bioavailability, terminal elimination half-life, and volume of distribution of prazosin is increased in the elderly. Hybrid drugs, such as ketanserin, urapidil, and indoramin are also effective in lowering blood pressure. Ketanserin seems to have a greater effect on blood pressure reduction in persons older than 60 years of age. Alpha1-adrenergic blockers may be used safely in patients with diabetes, asthma, and hyperlipidemia.

Management of hypertension and cardiovascular risk

Blood pressure reduction in hypertensive patients is a surrogate for the real therapeutic goal of reducing the risks consequent to hypertension. This surrogate is convenient but its use may have important therapeutic implications. Results of treatment with new antihypertensive agents, data from clinical trials, and insights into underlying mechanisms are reviewed. The overall success of antihypertensive therapy has been undeniable, but has reduced minimally the frequency of atherosclerosis and coronary events; metabolic disarray resulting from the agents used, especially thiazides and beta blockers, may have contributed to this. Electrolyte abnormalities predispose to malignant arrhythmias and sudden death during myocardial infarction. Left ventricular hypertrophy, a chief risk factor for coronary events, arrhythmias, and heart failure, responds selectively to antihypertensive agents. Similarly, progression of renal injury may be sensitive to the agents used. Obesity and hypertension frequently coexist. Evidence is growing that atherogenic abnormalities common in obese patients, such as insulin resistance, also occur in the nonobese patient and are sensitive to the antihypertensive agent selected.