Effect of acebutolol on left ventricular hemodynamics and anatomy in systemic hypertension

Effects of the single and repeated administration of benazepril on systemic and forearm circulation and cardiac function in hypertensive patients

The hemodynamic and cardiac effects of the new angiotensin-converting enzyme inhibitor, benazepril, were studied in 28 hypertensives in a double blind, placebo-controlled, between-patient study. Hemodynamic studies were performed noninvasively by means of M-mode echo (central hemodynamics and left ventricular systolic function), 2-D echo-Doppler (left ventricular diastolic function), and pulsed Doppler flowmetry (forearm circulation). Examinations were done at the end of a placebo run-in period and 3 hours after benazepril administration, both on the first day and after 6 weeks of treatment (10 or 20 mg once daily, according to patient response). In comparison with placebo, benazepril reduced systolic (p = 0.04) and diastolic (p = 0.003) blood pressure, because of a significant reduction in systemic vascular resistance (p = 0.03), while cardiac output was unchanged. Forearm vascular resistance was reduced and brachial artery compliance increased, although not to a statistically significant level (both p = 0.07). Both systolic and diastolic left ventricular function were positively influenced by the afterload reduction: End-systolic stress was reduced by 12% (p = 0.07), as was the late diastolic peak flow velocity (p = 0.02). All hemodynamic changes were evident after acute benazepril administration, and no differences was observed between acute and repeated treatment. We conclude that, similar to other ACE-inhibitors, benazepril reduces blood pressure through a reduction in vascular resistance, while cardiac output and heart rate are unaffected. These hemodynamic effects occur as early as after the first administration and exert a favorable influence on left ventricular dynamics.

Effects of a long-term treatment with alacepril on left ventricular hypertrophy and function in patients with essential hypertension

The authors examined the effects of a long-term treatment with the angiotensin-converting enzyme inhibitor, alacepril, with respect to the reversal of left ventricular hypertrophy and the improvement of left ventricular function. Ten uncomplicated essential hypertensive patients with left ventricular hypertrophy, aged 53 +/- 8 years, were treated with alacepril alone for 12 months. All patients underwent echocardiography to to assess left ventricular dimensions and function before and after the treatment. After the treatment, blood pressure was decreased significantly from 163 +/- 14.1/98 +/- 4.2 to 142 +/- 20.3/86 +/- 11.0 mm Hg (each, P less than .01), whereas heart rate did not change (66 +/- 6 versus 69 +/- 8 beats/min). The left ventricular mass index was decreased significantly from 146 +/- 27 to 119 +/- 29 g/m2 (P less than .01). Ejection fraction, fractional shortening, peak shortening rate, and peak lengthening rate all improved significantly after the treatment. There was a significant inverse relationship between fractional shortening and end-systolic wall stress before the treatment (r = .63, P less than .05), and this relationship did not change after the treatment. It is concluded that alacepril improved both left ventricular systolic and diastolic function without causing any consistent augmentation of left ventricular contractility.

Changes in left ventricular dimensions and systolic function in 100 mildly hypertensive men during one year's treatment with atenolol vs. hydrochlorothiazide and amiloride (Moduretic): a double-blind, randomized study

In a randomized double-blind study to compare the effect of atenolol vs. hydrochlorothiazide and amiloride (Moduretic) on left ventricular dimensions and systolic function, 100 hypertensive men were followed up during 1 year of treatment, 50 subjects being randomized to each drug. Echocardiography was performed at baseline, and after 3 and 12 months of treatment. A significant reduction in left ventricular mass with atenolol was paralleled by a decrease in left ventricular wall thickness and an increase in stroke volume. A similar reduction of left ventricular mass with Moduretic without a change in relative wall thickness and a decrease in stroke volume was observed. Cardiac output decreased in both groups.

Clinical use of beta-adrenoceptor blockade in systemic hypertension

beta-Blockers are effective in reducing the blood pressure of many patients with systemic hypertension. They differ in terms of the presence or absence of intrinsic sympathomimetic activity, membrane-stabilising activity, beta 1-selectivity, alpha-blocking properties, and relative potency and duration of action. All beta-blockers appear to have blood pressure lowering effects. The choice of which beta-blocker to use in an individual patient is determined by the pharmacodynamic and pharmacokinetic differences between the drugs in conjunction with the patient's other medical condition(s). This review discusses the practical use of beta-blockers and provides rational suggestions for which drug(s) to use in selected patient groups (Black, elderly, postinfarction, diabetes, renal disease, obstructive lung disease, elevated lipid levels, coexisting angina, and left ventricular hypertrophy).

Effect of celiprolol on large and small arteries of the forearm circulation in hypertensive patients

Celiprolol, a new highly cardioselective beta blocker, also has direct vasodilating properties. Since the noninvasive echo Doppler technique applied to the forearm circulation (brachial artery) allows the differentiation of arteriolar vasodilation (revealed by the increasing arterial blood flow velocity) from vasodilation of large arteries (shown by an increase in arterial diameter), it seems important to study the site of celiprolol's vasodilating effect. Thirty-five hypertensive patients, (21 male, 14 female; mean age, 59 +/- 11, range 42-79 years) were treated with increasing doses of celiprolol, 200 and 400 mg, over 15 days. The duplex echo Doppler technique (Aloka 7.5 M Hz probe) was used before and during each celiprolol dose period. Statistical analysis was performed by Student's paired t test. It was observed that celiprolol significantly increases the brachial artery diameter in a dose-dependent manner, and also increases the blood flow velocity (not being direct dose-related). Since the increase in diameter was clear with a higher dose, a dose-dependent increase in blood volume, a decrease in peripheral resistance, and an increase in compliance followed. Since the higher dose of celiprolol did not further reduce blood pressure (BP) in comparison to the lower dose, and a dose-dependent increase in arterial diameter and compliance occurred and a vasodilating effect of celiprolol on arterial wall ensued that was not related to BP. In conclusion, in the doses used, celiprolol dilates both arterioles and large arteries, but the mechanism of action needs to be clarified.

Cardiovascular protective properties of indapamide

Although indapamide has been used for many years as a first-line treatment of hypertension, it is only recently that some of its activities on the changes of the cardiovascular system, brought on by age and high blood pressure, have been studied. Indapamide appears to reduce blood pressure by a combined diuretic and direct vascular activity reducing vascular reactivity and total peripheral resistance. In addition, it has discrete effects on a number of interrelated systems that may protect the cardiovascular system. Indapamide reduces intracellular calcium levels, maintains magnesium ions, but reduces phosphate ions that may be involved in arterial rigidity. Circulating catecholamines remain unchanged but there is a reduction in normetanephrine, suggesting a reduction in sympathetic tone. It stimulates prostacyclin synthesis, increases levels of circulating prostacyclin, reduces platelet aggregation and stimulates the vasodilation elicited by endothelium-derived relaxing factor in the presence of bradykinin. In addition, it inhibits the formation of the vasoconstrictor prostanoid, thromboxane A2. The free radical scavenging activity of indapamide could also protect the vascular smooth muscle from the reperfusion injury of cerebral and myocardial ischemia. Indapamide induces a reduction in cerebral ischemia after carotid ligation. Unlike some other antihypertensives, it does not upset the high-density/low-density lipoprotein-cholesterol balance, reducing the possible risk of atherosclerosis. Moreover, the combination of binding to elastin and reduction in uptake of calcium and phosphate into the smooth muscle could be a mechanism for reducing arterial rigidity seen in the elderly and hypertensive patient. In hypertensive patients, these properties induce an improvement in arterial compliance, and in the long term a reduction in left ventricular hypertrophy. These pharmacologic and clinical results, together with a good antihypertensive efficacy and acceptability, suggest that indapamide may be a preferential agent in the long-term cardiovascular protection of the hypertensive patient.

Left ventricular hypertrophy reversal with labetalol and propranolol: a prospective randomized, double-blind study

Hypertensive patients with left ventricular hypertrophy (LVH) have increased cardiovascular morbidity and mortality. Experimental studies indicate the importance of both the alpha and beta components of the adrenergic nervous system in the development and reversal of LVH. Therefore labetalol (L), a combined alpha and beta blocker, and propranolol (P), a nonselective beta blocker, were evaluated in a randomized, double-blind study of 35 hypertensive patients with echocardiographic evidence of LVH. Following 2 weeks of placebo, L or P was titrated as needed and tolerated to maximum total daily doses of 1600 mg and 640 mg, respectively. A thiazide diuretic was added if necessary for blood pressure control. M-mode echocardiograms were performed at baseline and after 1, 3, 6, and 12 months of blood pressure control. The echocardiograms were read independently by two blinded observers for end-diastolic dimension and wall thicknesses, and left ventricular mass. Fractional shortening, cardiac output, and peripheral vascular resistance were derived using standard formulas. Both drugs reduced blood pressure significantly and comparably. Significant changes in the echocardiographic measurements were observed as early as 1 month and usually persisted throughout the study. Both drugs decreased posterior wall thickness; however, only the decrease in propranolol group achieved statistical significance. Septal wall thickness was reduced by L at 3 and 12 months. End-diastolic dimension increased significantly in the L-treated group at 3, 6, and 12 months of therapy, whereas P had no effect on this measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular mass changes with nicardipine therapy in essential hypertension

Eighteen hypertensive patients (13 males, 5 females; age 48 +/- 13; diastolic blood pressure greater than 95 mmHg), either previously untreated or who had been off treatment for more than 3 months, underwent M-mode echocardiography before (DO) and after (D90) 3 months of nicardipine therapy (60-90 mg/day). All echocardiograms were read blind, and left ventricular mass (LVM) was calculated (Devereaux's formula). Blood pressure was significantly reduced after 3 months from 167 +/- 15/102 +/- 8 mmHg on DO to 152 +/- 16/92 +/- mmHg on D90 (p less than 0.001). The reduction in LVM was not significant: 266 +/- 95 g on DO, 247 +/- 78 g on D90. There was a trend to a higher (although nonsignificant) LVM reduction in patients with left ventricular hypertrophy at entry (-11%, n = 11) than in patients without left ventricular hypertrophy (-2%), n = 7).

Hemodynamic effects of dilevalol in patients with systemic hypertension and left ventricular dysfunction

Hemodynamic and left ventricular function parameters were measured in patients with mild to moderate hypertension and compromised left ventricular function who were given dilevalol, an antihypertensive agent with selective beta 2-agonism and nonselective beta-antagonist activity. After a 2- to 3-week placebo washout period, 9 patients were given dilevalol titrated upward from 100 to 600 mg twice daily over a 7-week period to achieve a supine diastolic blood pressure of less than 90 mm Hg with a decrease of greater than or equal to 10 mm Hg from baseline. Multigated radionuclide ventriculography and systolic and diastolic time intervals were performed after the pretreatment placebo washout, at the end of 2 weeks' maintenance dosing, and after a 7- to 10-day post-treatment discontinuation and placebo washout period. At an average daily dose of dilevalol, 444 mg, heart rate at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. Systolic and diastolic blood pressures at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. At maximal exercise, changes in blood pressure and heart rate were significantly blunted (p less than 0.05) during treatment. Ejection fraction at rest increased significantly (p less than 0.01) during treatment, with no significant change occurring during exercise, and decreased during post-treatment placebo. Preejection period decreased significantly during treatment (p less than 0.005) and increased during post-treatment placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Regression of left ventricular hypertrophy on long-term treatment with captopril of severe hypertensives refractory to standard triple treatment

Ten patients (mean age 53 years; range 37-65 years) with hypertension refractory to standard triple treatment were selected for measurement of blood pressure and echocardiographic evaluation of the left ventricular dimensions before and after 3, 6 and 12 months of captopril therapy. In each patient the dose of captopril was titrated to a maximum of 150 mg t.d.s. (range 25 to 150 mg t.d.s.) with a therapeutic goal of less than or equal to 90 mm Hg diastolic blood pressure. Most patients had added diuretic therapy. Four patients were unable to complete the study, two because of insufficient response to captopril therapy, and two because of side-effects (skin rash and cough). A significant fall in blood pressure was seen after three months of treatment and a reduced blood pressure was still maintained after 12 months. Over the same period, the average number of drugs was reduced from 3.6 to 2.1 per patient. A gradual reduction of septal and posterior wall thickness were noted, from 12.8 and 11.5 mm to 10.0 and 8.5 mm, respectively, after 12 months. Calculated left ventricular muscle mass was insignificantly reduced from 281 to 243 g after 12 months. The present study suggests that in hypertension resistant to conventional multiple therapy, captopril can reduce the blood pressure, and, in the long run it can also induce reversal of left ventricular wall thickening without causing deterioration of left ventricular function.

Pulsatile diameter and elastic modulus of the aortic arch in essential hypertension: a noninvasive study

A noninvasive evaluation of the aortic arch diameter was performed in 16 subjects with sustained essential hypertension and in 15 normal subjects of similar age, gender and body surface area. In all subjects, measurements were obtained of brachial mean arterial pressure and pulse pressure, cardiac mass (judged on echocardiography) and carotid-femoral pulse wave velocity together with ultrasound determinations of aortic arch diastolic and systolic diameter (suprasternal window). For each subject, pulsatile change in aortic diameter, strain and aortic arch elastic modulus were calculated. Compared with normal subjects, the hypertensive subjects showed an increase in aortic arch diameter (diastolic diameter 29.6 +/- 1.0 versus 25.4 +/- 1.0 mm, p less than 0.01), in elastic modulus (1.071 +/- 0.131 versus 0.526 +/- 0.045 10(5) N.m-2, p less than 0.001) and pulse wave velocity (11.8 +/- 0.5 versus 8.9 +/- 0.3 m/s, p less than 0.001). In the study group, a positive correlation was observed between diastolic aortic arch diameter and mean arterial pressure (r = 0.54, p less than 0.01) and between elastic modulus and cardiac mass (r = 0.60, p less than 0.01). Elastic modulus and age were positively correlated (r = 0.73, p less than 0.01) in hypertensive but not in normal subjects (r = 0.08, NS). This study is the first to demonstrate noninvasively that both the aortic arch diameter and the elastic modulus are increased in patients with sustained uncomplicated essential hypertension. These findings suggest that the increase in elastic modulus could influence the development of cardiac hypertrophy, and that both age and blood pressure act independently as factors that alter the arterial wall of subjects with sustained essential hypertension.

Radiological heart enlargement in treated hypertensive men: a comparative study of chest X-ray examination and M-mode echocardiography

Twenty-five hypertensives with no history of myocardial infarction and with a radiologically determined heart enlargement were examined with M-mode echocardiography and compared with a normotensive control group (n = 41). All except two of the hypertensive patients were on a beta-blocker based antihypertensive treatment regime. The relative heart volume on X-ray was significantly larger in the hypertensives, 562 ml m-2 body surface area (BSA), compared to the normotensives, 408 ml m-2 BSA (P less than 0.001). Both left ventricular diameter (LVD) in end-diastole and end-systole and left arterial (LA) diameter were significantly larger in the hypertensives (56 vs. 51 mm, P less than 0.01; 35 vs. 31 mm, P less than 0.01; 46 vs. 42 mm, P less than 0.01, respectively) as was the LV mass (296 vs. 203 g, P less than 0.001). The end-systolic wall stress (ESWS) was significantly greater in the hypertensives. Despite these findings resting left ventricular fractional shortening was the same and showed a similar correlation with ESWS (r = 0.79 and r = 0.77, respectively) in both groups. Hence, left ventricular systolic performance was not impaired in the hypertensives compared to the normotensives. These results show that an enlarged cardiac silhouette on the chest X-ray in hypertensive subjects with beta-blocker based drug therapy must be interpreted with caution and must not, a priori, be judged as a sign of an impaired systolic cardiac function.

Carteolol, an antihypertensive beta-blocker with intrinsic sympathomimetic activity, reduces ECG evidence of left ventricular hypertrophy

Effective treatment of chronic hypertension may be accompanied by a decrease, increase, or no change in the extent of LVH, depending on the pharmacologic properties of the antihypertensive agents employed. Unlike beta-adrenoceptor blockers without ISA, beta-adrenoceptor blockers with ISA have been reported to increase left ventricular mass despite favorable reductions in blood pressure. To assess further the potential effect of ISA on LVH, we retrospectively evaluated the effect of carteolol, a nonspecific beta-adrenoceptor antagonist with strong ISA, upon ECG evidence of LVH. In 12 patients with LVH, carteolol treatment for one year reduced mean arterial blood pressures from 120 +/- 2 mm Hg to 100 +/- 2 mm Hg and mean hypertrophy scores from 5.2 +/- 0.6 to 2.6 +/- 0.8. Therefore, ISA does not preclude the regression of ECG evidence of LVH during the treatment of hypertension.

Cardiac function in systemic hypertension before and after reversal of left ventricular hypertrophy

In 3 age- and sex-matched groups of subjects--15 normotensives, 15 hypertensives without left ventricular (LV) hypertrophy and 15 hypertensives with LV hypertrophy--the slopes of the regression line obtained by plotting the individual values of LV fractional shortening against the corresponding values of echocardiographic end-systolic stress were compared. The first 2 groups were studied only in control conditions while the third group was restudied after a 20% reduction in LV mass index induced by a long-term antihypertensive treatment and after a 3-week washout period. A significant relation between fractional shortening and end-systolic stress was found in all instances. The slope of this correlation was higher in normotensives (-0.251) and in hypertensives without LV hypertrophy (-0.232) (both p less than 0.01) than in hypertensives with ventricular hypertrophy (-0.079). In this latter group, the slope increased after the reversal of LV hypertrophy (-0.230, p less than 0.01) and remained unchanged (-0.202) at the end of the washout period. No difference was detectable between the slopes obtained in these patients after reversal of LV hypertrophy, both with the antihypertensive treatment on and off, and those of normotensives and hypertensives without LV hypertrophy. Thus, LV hypertrophy attenuates the influence of changes in afterload on LV function. Reversal of LV hypertrophy restores a fractional shortening end-systolic stress relation quite comparable to that found both in normotensives and in hypertensives before the development of LV hypertrophy.

Beta blockers and left ventricular hypertrophy in hypertension

It is now generally accepted that hypertension-induced left ventricular hypertrophy (LVH) represents a phenomenon of multifactorial origin. Antihypertensive therapy with beta-blocking drugs influences most of the factors involved in the control of left ventricular mass. Therefore, although initial animal experiments yielded conflicting results, it is not surprising that a great deal of evidence has been accumulated in clinical studies showing that successful long-term antihypertensive treatment with beta blockers induces regression of LVH in hypertensive subjects. Differences in molecular structure among various beta-blocking agents do not seem to influence this property. On the contrary, the question of whether reversal of LVH represents a beneficial or harmful byproduct of antihypertensive treatment with beta blockers is still unanswered. Animal and clinical studies suggest that left ventricular systolic function is unchanged or even improved after regression of LVH, whereas the ability of the heart to withstand recurrence of hypertension is slightly reduced. Furthermore, development of LVH in hypertensive subjects is associated with abnormalities in diastolic function which are not reduced by reversal of LVH induced by antihypertensive treatment with beta blockers.

Effects of celiprolol on systemic and forearm circulation in hypertensive patients: a double-blind cross-over study versus metoprolol

The antihypertensive efficacy of a new beta-receptor blocking agent, celiprolol, was compared with that of a well-established antihypertensive drug, metoprolol. Their systemic and forearm hemodynamic effects were investigated using echocardiography and two-dimensional pulsed Doppler flowmetry, respectively. Twenty hypertensive patients completed a double-blind, cross-over, randomized study using celiprolol and metoprolol. Two six-week courses with celiprolol or metoprolol were preceded and followed by a two-week placebo period; the total duration of the study was 18 weeks. In spite of a comparable efficacy in reducing systolic and diastolic blood pressure (about 10% of the basal value), the two drugs showed quite different systemic and regional hemodynamic effects. Celiprolol induced a significant decrease in forearm vascular resistance (from 157 +/- 17 to 113 +/- 13 mm Hg/mL/s, P less than .01) and total peripheral resistance (from 1596 +/- 90 to 1398 +/- 91 dyne.s.cm-5, P less than .05) whereas cardiac output remained unchanged and forearm blood flow increased. Metoprolol reduced cardiac output (from 6.5 +/- 3 to 5.7 +/- 3 L/min, P less than .05), through a reduction in heart rate, since stroke volume was unchanged. Both drugs did not significantly modify cardiac performance, as evaluated by left ventricle fractional shortening and ejection fraction. Thus, the two drugs seem to reduce blood pressure through different hemodynamic mechanisms.

Acebutolol: a review of its pharmacology, pharmacokinetics, clinical uses, and adverse effects

Acebutolol is a new hydrophilic, cardioselective beta-adrenergic-blocking agent that possesses partial agonist and membrane-stabilizing activities. In the treatment of mild to moderate essential hypertension, once-daily acebutolol as monotherapy provides effective control in a large majority of patients and produces a further reduction in blood pressure when used concomitantly with diuretics. Acebutolol is as effective as other beta-blocking agents, and in a large, double-blind, parallel study against propranolol was found to cause less reduction in heart rate, and fewer neurologic side effects and patient withdrawals due to adverse effects. Oral acebutolol is also effective in suppressing premature ventricular contractions, and in small numbers of patients generally beneficial results were obtained in supraventricular and ventricular arrhythmias with intravenous administration. These salutary effects are attributable to beta blockade. Controlled clinical trials documented the antianginal actions of oral acebutolol in chronic stable angina pectoris; its efficacy in this regard is comparable to that of other beta-blocking agents. The drug produces smaller decreases in heart rate and cardiac output and alterations in peripheral vascular hemodynamics than beta-blocking drugs without partial agonist activity, and because of its cardioselectivity, it may be used cautiously in patients with bronchospastic disease. Acebutolol has minimal metabolic effects and does not elevate levels of blood lipids during long-term therapy; high-density-lipoprotein cholesterol increased with acebutolol in a small number of patients.

Left ventricular mass and systolic performance in chronic systemic hypertension

This study was undertaken to define the relation between the extent of left ventricular (LV) hypertrophy and ventricular systolic performance in patients with chronic systemic hypertension. Ninety patients with chronic systemic hypertension were compared with 41 normal subjects as determined by angiography. LV mass was estimated from the M-mode echocardiogram. Patients were separated into 3 groups: those with LV mass of less than 2 (group I, n = 58), 2 to 4 (group II, n = 21) and more than 4 (group III, n = 11) standard deviations above mean normal. The ratio of preejection period to LV ejection time (PEP/LVET), percent shortening of the echocardiographic internal diameter (% delta D) and velocity of circumferential shortening (Vcf) were used as indexes of LV systolic performance. The frequency of abnormality, expressed as percent of patients in groups I, II and III, was 33%, 55% and 85% for PEP/LVET, 15%, 35% and 72% for % delta D, and 0%, 15% and 55% for Vcf. For each group PEP/LVET was the most frequently abnormal measure and Vcf was the least frequent abnormality. Calculation of peak and end-systolic wall stress was used as an index of the adequacy of LV hypertrophy. This index was significantly reduced in group I, did not differ from control in group II and was significantly increased in group III, indicating that hypertrophy was appropriate to wall tension in groups I and II. It is concluded that the occurrence of LV dysfunction with increasing LV mass in patients with moderate LV hypertrophy (group I and II) reflects a deficiency in intrinsic contractile performance of the hypertrophied myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Sequential echocardiographic study prior and during antihypertensive therapy in children with severe hypertension

This study was performed to assess myocardial involvement in 18 children with severe hypertension (HT), using two dimensional (2D) guided M mode echocardiography, prior and during therapy. All patients but 2 had renal or renovascular disease. Septal diastolic thickness (SDT) was utilized as a serial marker. Except for one case, all patients had increased SDT initially (1.03 +/- .26 cm/m2, p less than .01 vs normal). Evolution under therapy allowed subdivision of patients: Group I: 12 patients showed left ventricular (LV) hypertrophy regression, within a follow-up period of 20 +/- 9 months (final SDT: .78 +/- .12 cm/m2 vs initial 1.09 +/- .28, p less than .01). Blood pressure (BP) was normalized in 9 patients, and borderline in 3. Therapy consisted on acebutolol (n = 10), captopril (n = 1), and renal artery surgery (n = 1). Group II: LV hypertrophy was unchanged (n = 3) or increased (n = 3), within a follow-up period of 19 +/- 8 months, with persistent severe (n = 3) or mild (n = 3) HT, under acebutolol (n = 5). Treatment was changed to captopril with subsequent normal BP and echocardiogram improvement (n = 3). In the overall population, final SDT was significantly correlated to the final BP (r = .69, p less than .01). In conclusion, echocardiographic follow-up allowed serial non invasive assessment of LV hypertrophy in our severely hypertensive pediatric population. At first echocardiogram, LV hypertrophy was present in all patients but one. Antihypertensive therapy allowed simultaneous decrease of BP and LV hypertrophy in 12 patients, 10 under acebutolol.

Indenolol: a new antihypertensive agent: efficacy, toxicity, and hemodynamic effects in a crossover double-blind study with metoprolol

The antihypertensive efficacy of a new agent, indenolol, was compared with that of the well-established antihypertensive drug, metoprolol, and its hemodynamic effects were investigated using echocardiography. Eighteen hypertensives completed a double-blind, crossover, randomized study using indenolol and metoprolol. Two four-week courses with indenolol or metoprolol were preceded and followed by a two-week placebo period; the total duration of the study was 14 weeks. Indenolol proved to be significantly more effective than metoprolol in decreasing blood pressure values at rest (P less than .05). Furthermore, three patients that failed with metoprolol were successfully treated with indenolol. Both drugs induced a significant decrease in cardiac output that was mediated mainly through a reduction in heart rate, because stroke volume, left ventricle circumferential fiber shortening velocity, and ejection fraction were not significantly reduced by either drug. However, after indenolol, a significant direct relationship was found between the basal values of both cardiac output (r = .809) and total peripheral resistance (r = .800), and the reduction of these parameters. On the contrary, after metoprolol only, the correlation between the basal value of cardiac output and its reduction was significant (r = .790).

Participation of endogenous catecholamines in the regulation of left ventricular mass in progeny of hypertensive parents

To investigate whether adrenergic activity is a determinant of left ventricular hypertrophy in human hypertension, in each of 10 normotensive subjects with two hypertensive parents we have examined the relationship between changes in echocardiographic parameters of left ventricular anatomy and those in circulating catecholamine levels induced by three, 3 week periods of different sodium and potassium intakes. A high sodium-normal potassium regimen induced a significant reduction in upright plasma norepinephrine (from 599 +/- 89 to 379 +/- 45 pg/ml, p less than .01) and in posterior wall (PWT) and interventricular septal (IVST) thickness, as well as in the left ventricular mass index (LVMi). Changes in upright plasma norepinephrine concentrations correlated with those in IVST (r = .822, p less than .01) and in LVMi (r = .833, p less than .01). A low sodium-normal potassium diet resulted in increases in supine and upright plasma norepinephrine levels (from 356 +/- 44 to 488 +/- 89 pg/ml, p less than .001; and from 565 +/- 42 to 744 +/- 33 pg/ml, p less than .01) as well as increases in IVST and LVMi (from 97 +/- 7 to 107 +/- 7 g/m2, p less than .001). The changes in norepinephrine levels in supine and upright subjects correlated with changes in IVST (r = .836, p less than .01 and r = .796, p less than .01) and in LVMi (r = .931, p less than .001 and r = .947, p less than .001). No significant change in plasma catecholamine concentrations or in PWT, IVST, or LVMi was detected after a low sodium-high potassium regimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac hypertrophy and arterial distensibility in essential hypertension

Echocardiographic determinations, left ventricular mass-volume ratio (M/V), left ventricular end-systolic stress (ESS), carotidofemoral pulse wave velocity (PWV), and brachial artery compliance (BAC), deduced from pulsed Doppler measurements and from the Bramwell-Hill equation, were evaluated in 20 patients with sustained essential hypertension in comparison with 20 control subjects of the same age and sex. In hypertensive patients, M/V ratio, ESS, and PWV were significantly increased while BAC was reduced. In the overall population, ESS was directly correlated with PWV (r = 0.73), and M/V ratio was significantly correlated with PWV (r = 0.60), BAC (r = -0.70), and systolic arterial pressure (r = 0.71). No comparable results were observed with diastolic arterial pressure. PWV was unchanged after cadralazine, a dihydralazine-like substance, and was decreased with the same blood pressure reduction following nitrendipine, a new calcium-blocking agent. These results suggest that: (1) the distensibility of large arteries plays an important role in the maintenance of cardiac hypertrophy in hypertension, and (2) antihypertensive drugs may act differently on arterial distensibility with possible consequences on ESS and reversion of left ventricular hypertrophy.

The therapeutic implications of diastolic time changes in systemic hypertension

Twenty-five patients with chronic systemic hypertension were studied. Systolic time intervals and diastolic time were determined at baseline and after 12 weeks of therapy with nadolol, with or without bendroflumethiazide (treatment phase I), then after 12 weeks of therapy with hydralazine, bendroflumethiazide, or both (treatment phase II). Systolic, diastolic, and mean blood pressures were equally controlled after either treatment regimen. Heart rate was significantly slower after treatment phase I compared to baseline or after treatment phase II (p less than 0.001). Systolic time per minute was significantly shorter and diastolic time per beat and per minute were significantly longer after treatment phase I compared to baseline or after treatment phase II (p less than 0.001). Double and triple products decreased after either mode of therapy; however, these parameters were significantly lower after treatment phase I compared to treatment phase II (p less than 0.01). These changes in systolic and diastolic time and double and triple products may be of clinical significance during therapy of chronic systemic hypertension and may help explain the regression of left ventricular hypertrophy in patients with hypertension treated with sympathetic blocking agents.

Effect of acebutolol on left ventricular performance

The effect of acebutolol on left ventricular performance was examined by various noninvasive means in three studies. M-mode echocardiographic measurements were made in 21 patients with coronary artery disease who were receiving placebo, acebutolol, and propranolol in a double-blind, randomized, crossover study. In these patients with normal or near-normal resting left ventricular function, neither drug induced depression of left ventricular function. In 26 patients with chronic angina pectoris receiving acebutolol under double-blind, placebo-controlled conditions, gated (equilibrium) myocardial blood pool imaging using red blood cells labeled with technetium 99m showed acebutolol to have no clinically significant negative effect on left ventricular performance at rest or during supine bicycle exercise. Acebutolol at effective antianginal doses modestly improved resting global and regional myocardial function. In 13 patients with stable angina pectoris, single-pass studies of left ventricular function with indium 113 under double-blind, placebo-controlled conditions similarly showed acebutolol to have no clinically significant negative inotropic effects. In conclusion, acebutolol is safe for use in patients with coronary disease and a wide range of ejection fractions but, as with all beta blockers, should be used cautiously in patients with markedly reduced resting left ventricular function.

Acebutolol: ten years of experience

During 10 years of clinical use involving almost 3 million patient-years, acebutolol has become established as a remarkably safe and well-tolerated beta-blocking agent, effective in treating essential hypertension and cardiac arrhythmias. The existence of a long-lived active metabolite (diacetolol) confers a 24-hour duration of action, which permits effective use of a once-daily regimen, particularly for hypertension. Acebutolol has low lipid solubility and low protein binding; the former property reduces the risk of central side effects, and the latter means that displacement interactions with other drugs are unlikely. Because acebutolol and its metabolite normally have both renal and hepatic excretion pathways, an alternative pathway is available should either be compromised through disease. Acebutolol is cardioselective, and clinical use has borne out the low incidence of bronchospasm in patients with impaired lung function. The possession of intrinsic sympathomimetic activity (ISA) leads to only modest reductions in cardiac output, which in turn reduces the chance of excessive bradycardia and the likelihood of precipitating heart failure. A combination of selectivity and ISA may be responsible for the low incidence of tiredness and cold extremities observed with acebutolol compared with other beta blockers. The unique pharmacologic and pharmacokinetic profile of acebutolol confers several therapeutic advantages and may be responsible for the generally low level of side effects experienced in clinical use.

Effects of a fixed combination of low dose nifedipine and acebutolol on essential hypertension: comparison with standard dose acebutolol

114 patients from four clinics participated in a double blind study designed to assess the efficacy of a nifedipine-acebutolol fixed combination -10 mg + 100 mg - as compared with acebutolol -200 mg- in essential hypertension. During the ten week study the mean blood pressure readings (s.d.) 1-3 h after treatment decreased from 179.2/104.8 (10.2/6.2) to 150.3/87.7 (9.8/7.7) in the combination group and from 181.7/106.5 (14.4/7.0) to 150.4/89.0 (15.0/10.4) in the acebutolol group. The mean systolic and diastolic blood pressures were also decreased after exertion (load) and 24 hours after treatment at the end of the 6th week of the study. A doubling of the dose from week 7 to 10 did not change these figures. These results reveal the possibility of treating essential hypertension with a low dose of beta-adrenergic blocking agents in combination with 10 mg nifedipine. Both drugs were well tolerated. 3 patients (5%) in the combination group and 3 patients in the acebutolol group were withdrawn from the study because of headache and dizziness.

Role of prostaglandins in the renal handling of a salt load in essential hypertension

Renal function and systemic hemodynamics were assessed in 10 hypertensive patients and in 10 age-matched normotensive subjects during control conditions (80 mEq of sodium/day) and after a salt load, either alone (480 mEq/day) or combined with indomethacin or sulindac. Indomethacin was used to induce ubiquitous inhibition of prostaglandin synthesis and sulindac to inhibit prostaglandin synthesis in all tissues except the kidney. Under control conditions there was no significant difference between the 2 groups in any measurement except blood pressure and total peripheral resistance. Also, the changes induced by salt load in the 2 groups were comparable. However, after indomethacin administration, only hypertensive patients showed a significant reduction in the 24-hour sodium excretion (from 417 +/- 61 to 317 +/- 49 mEq, p less than 0.05), so that the difference between this value and the corresponding value of normotensive subjects (453 +/- 79 mEq) became significant (p less than 0.05). The changes in sodium excretion in hypertensive patients were significantly correlated with the changes in renal plasma flow (r = 0.803, p less than 0.01). However, cardiac output and renal blood flow showed a similar pattern in normal and hypertensive persons. Finally, after the addition of sulindac to salt load, the differences in the 24-hour sodium excretion vanished. These results were also confirmed in an ancillary study performed, using the same protocol, in 10 other hypertensive patients using ibuprofen rather than indomethacin. Our data suggest that renal prostaglandins participate in renal disposal of chronic salt load in hypertensive patients but not in normal persons.