Coronary heart-disease after treatment of hypertension

Within a group of 1026 men aged 47-54, cause-specific death-rates and the incidence of non-fatal myocardial infarction and stroke in treatment group of 635 hypertensive men (casual systolic B.P. greater than 175 or diastolic B.P. greater than 115 mm Hg on two occasions) treated at a hypertension clinic were compared with those in a control group of 391 men (causal systolic B.P. greater than 175 or diastolic greater than 115 mm Hg on only one occasion) who remained mainly untreated during their 4.3 years of follow-up. The predicted risk of coronary heart-disease (C.H.D.) at entry, calculated by a multiple logistic function, was slightly higher in the treatment group. Total death-rate during follow-up was significantly lower in the treatment group (3.3%) than in the control group (6.1%). The difference in death-rate for C.H.D. was of the same relative order (0.8% versus 1.5%), as was the incidence of non-fatal myocardial infarction (2.8% versus 5.4%), although none of the differences reached statistical significance. However, the pooled incidence of fatal and non-fatal C.H.D. was significantly lower in the treatment group (3.6%) than in the control group (6.9%). The results suggest that antihypertensive treatment might be effective in preventing or postponing C.H.D. in middle-aged men.

Controlled trial of acebutolol in hypertension

Acebutolol, a new cardioselective beta-adrenoceptor blocking agent, has been evaluated for the treatment of hypertension. Thirty eight previously untreated male patients with essential hypertension received placebo treatment during a 4-week run-in period, and then they were randomly (double-bind) allocated either to continued placebo treatment for three 4-week periods or to treatment with acebutolol 400, 600, and 1200 mg daily, respectively, for three 4-week periods. Blood pressure and heart rate were recorded at the end of each 4-week period. Treatment with acebutolol produced statistically significant reductions in blood pressure and heart rate as compared to the placebo regimen.

Prolonged exposure to a stressful stimulus (noise) as a cause of raised blood-pressure in man

Systolic and diastolic blood-pressure was significantly higher in 44 male industrial workers with a noise-induced auditory impairment (greater than or equal to 65 dB at 3000, 4000, or 6000 Hz) than in 74 males of the same age with normal hearing. Moreover, significantly more individuals with hypertension (resting recumbent blood-pressure greater than or equal to 160/100 mm Hg) were found in the group with noise-induced loss of hearing. It is suggested that replaced and prolonged exposure to a stressful stimulus (industrial noise severe and prolonged enough to cause a permanent loss of hearing at the relevant frequencies) may be a contributing factor to the rise in blood-pressure through a mechanism involving structural adaption of blood-vessels in response to repeated peaks of raised blood-pressure.

Effects of blood pressure reduction on the structural vascular abnormality in skin and muscle vascular beds in human essential hypertension

1. Vascular resistance at maximal vasodilatation was examined in two vascular beds in two groups of hypertensive patients and in normotensive control subjects before and during anti-hypertensive therapy in the hypertension groups. 2. In one group of twelve untreated patients with essential hypertension, examined with plethysmography and intra-arterial blood pressure recording, a significantly higher vascular resistance at maximal vasodilatation was found in the hands compared with normotensive control subjects matched for age, sex, weight and height. This indicated a structural vascular abnormality in the patient group. 3. After 5 years of anti-hypertensive therapy in the patient group the difference in vascular resistance between patients and control subjects had decreased significantly, indicating a reversibility of the structural vascular abnormality. 4. Vascular resistance at maximal vasodilatation was examined in the calves of twelve untreated patients with essential hypertension and fourteen normotensive control subjects. Plethysmographic technique and indirect blood pressure recordings were used. A significantly higher vascular resistance was found in patients than in control subjects, indicating a structural vascular abnormality also in this vascular bed. 5. Anti-hypertensive treatment for 6 months in the patient group did not change vascular resistance at maximal dilatation, indicating that the structural vascular abnormality remained. 6. During acute reduction of blood pressure in hypertension by means of trimethaphan infusion, blood pressure and blood flow to the hands were reduced proportionally with no change of vascular resistance at maximal vasodilatation. 7. This indicates that resistance at maximal dilatation was unaffected by the acute reduction of blood pressure, in contrast to the findings after prolonged reduction of blood pressure in this vascular bed.

Clinical evaluation of atenolol in hypertension

1. Atenolol (ICI 66.082, Tenormin) is a new beta-adrenoreceptor-blocking agent, devoid of intrinsic sympathomimetic and membrane-stabilizing properties. It does not cross the blood-brain barrier. 2. Atenolol given to hypertensive patients in initial open trials reduced arterial blood pressure significantly. 3. A double-blind comparison between atenolol and placebo in forty-five patients with essential hypertension demonstrated that atenolol gave a statistically significant reduction of blood pressure (delta 28/15 mmHg, P less than 0-005). 4. The optimum anti-hypertensive dose of atenolol in patients with mild to moderately severe essential hypertension was 200 mg daily. 5. Atenolol was compared with propranolol in thirty patients with essential hypertension. No statistically significant differences of anti-hypertensive effect were observed between the two drugs. 6. Long-term results (up to 2 years) in 117 hypertensive patients indicate that drug tolerance is good. No serious toxic effects were observed. 7. In four of twelve hypertensive patients with obstructive airways disease atenolol had to be withdrawn owing to deterioration of ventilatory function.

Antihypertensive effect of labetalol, a new alpha- and beta-adrenergic blocking agent

Labetalol (AH5158) a new alpha- and beta-adrenergic blocking agent was given to 12 hypertensive patients for an average of 7 months. Statistically significant and clinically relevant reductions of blood pressure both in the recumbent and standing positions were observed. Side effects were few and the absence of postural hypotension was noted.

Labetalol, a new alpha- and beta-adrenoreceptor blocking agent, in hypertension

1Labetalol is a new compound with antagonistic effects at both alpha- and beta-adrenoreceptor sites. 2 When given to 12 hypertensive patients at an average daily dosage of 273 mg for 7 months statistically significant reductions (compared with pretreatment values) in recumbent and standing blood pressure were observed. 3 Treatment has to be withdrawn in one patient because of vivid dreams, and dosage was reduced in one patient because of dizziness. Otherwise no side-effects of importance were noted. 4 It can therefore be concluded that labetalol offers a useful anti-hypertensive effect and that this compound is well tolerated.

Anti-hypertensive action, time of onset and effects on carbohydrate metabolism of labetalol

1 Seventeen men, aged 45-57 yr, with essential hypertension showed obvious and, in the standing position, dose-related reductions in blood pressure during treatment with oral labetalol with weekly dose increments. 2 Pulse rate changes were not related to dose but reduced compared with pre-treatment values. 3 No postural hypotension was recorded indicating lack of a dominant alpha-adrenoreceptor-blocking component. 4 There was a small increase in mean fasting blood glucose levels during labetalol treatment but no alteration in insulin activity or response to an oral glucose tolerance test.

Heart rate responses during treatment of hypertension with propranolol. The clinical usefulness of the nitroglycerin test

Increments in heart rate during the TNG test (sublingual nitroglycerin with assumption of upright posture), passive head-up tilt, and postrecumbency standing were compared to the effects of intravenous isoproterenol in 15 mild hypertensives during administration of placebo and two dosage levels of propranolol. TNG test results correlated with responsiveness to isoproterenol, but nitroglycerin tachycardia was reduced only about 50% during propranolol treatment. The TNG response was almost maximally inhibited by 160 mg/day of propranolol while the response to postrecumbency standing was inhibited only by a dose of 320 mg/day. The results indicate that: (1) the TNG test is of limited value in the assessment of beta adrenergic blockade in hypertensive patients, and (2) propranolol in a dose of 160 mg/day induces near-maximal cardiac blockade.

A comparison of the antihypertensive effect of atenolol (ICI 66 082) and propranolol

Propranolol was given to 30 patients with essential hypertension following randomised, double-blind administration of either placebo or a new cardioselective beta-adrenergic receptor antagonist, atenolol (Tenormin, ICI 66 082). Both atenolol and propranolol caused statistically significant reduction of recumbent and erect blood pressure and heart rate. There were no important differences between these variables on comparison of atenolol and propranolol.

Controlled study of atenolol in treatment of hypertension

The antihypertensive effect of atenolol, a new beta-1-receptor blocking agent, was studied in a double-blind trial in which 45 patients with essential hypertension were randomly assigned to placebo or atenolol treatment. Atenolol caused a statistically significant and clinically relevant reduction of blood pressure. The optimum daily dose for moderately severe hypertension was considered to be 200 mg. Several irrelevant side effects were collected by the use of a check list, but there was no difference in the number of complaints during placebo and active treatment. Atenolol has a useful antihypertensive effect and, at least theoretically, has advantages over other beta-adrenergic blocking agents.

Effect of high dose spironolactone and chlorthalidone in essential hypertension: relation to plasma renin activity and plasma volume

The effect on blood pressure of high (400 mg/day-S400) and moderate dose (200 mg/day-S200) spironolactone and chlorthalidone (100 mg/day-C100), given in a random double-blind manner was related to plasma renin activity and plasma volume in 38 essential hypertensives. The fall in pressure from a control of 154/103 mm Hg was essentially the same after four weeks of each drug--S400 deltaBP 24/13 mm, S200 18/9 mm, C100 17/12 mm (all P less than 0-001). Twelve of 37 patients (32%) had low initial renin, but this appeared as responsive to the chlorthalidone stimulus as that of the normal renin group. The antihypertensive effect of all regimens was unrelated to plasma renin activity. Plasma volume was significantly lowered at the end of each treatment period, but the decline could not be correlated with blood pressure effects. Patients with initially low plasma volume were more likely to respond to S400 (r = 0-545, P less than 0-001), whereas the antihypertensive effect of the S200 and C100 regimens was independent of this variable.