Comparison of central and peripheral haemodynamic effects of dilevalol and atenolol in essential hypertension

A new non-imaging echo-Doppler cardiac output device that works on the principle of attenuated compensation volume flow (ACVF), has been used to assess the cardiovascular effects of atenolol and dilevalol in 24 patients with essential hypertension. Compared with the baseline, one month of atenolol reduced systemic mean arterial blood pressure (12 mmHg; P less than 0.01), heart rate (-24 bpm; P less than 0.001), aortic velocity integral (-2.1 cm/sec; P less than 0.01) without a change in cardiac output or systemic vascular resistance. Dilevalol reduced systemic mean arterial pressure (-12 mmHg; P less than 0.01) and heart rate (-13 bpm; P less than 0.01), without a change in cardiac output or aortic velocity integral; systemic vascular resistance fell (-149 dyne/sec; P less than 0.01). Thermography and skin thermal clearance techniques were used to assess the effects of each compound on the peripheral circulation; both compounds reduced skin temperature and thermal clearance but the changes were more marked for atenolol than dilevalol. These results suggest that the mechanism of action of dilevalol is, in part, different from atenolol and would be compatible with a direct vasodilator action on the peripheral vasculature.

Pharmacodynamic monitoring during acute intervention in ischaemic heart disease using a new echo-Doppler device

1. We have utilised a new non-imaging echo-Doppler cardiac output device, using the principle of attenuated compensated volume flow (ACVF), to assess the cardiovascular effects of atenolol and buccal nitroglycerin (NTG) in a placebo-controlled study of 30 patients with coronary disease. 2. Atenolol (4 mg i.v.) reduced heart rate, cardiac output and time-averaged mean aortic velocity (P less than 0.01) and increased systemic vascular resistance (P less than 0.01). 3. Buccal NTG (5 mg) reduced systemic mean arterial pressure (P less than 0.01), cardiac stroke volume (P less than 0.05) and stroke length (P less than 0.01). 4. Thus although both drugs reduced time-averaged aortic velocity (an index of cardiac performance), the concomitant reduction in cardiac stroke length and tachycardia suggested sub-optimal cardiac filling for buccal NTG, whereas for atenolol (with the associated increased systemic vascular resistance but unchanged stroke length) attenuation of sympathetic stimulation at cardiac beta-adrenoceptors. 5. The ACVF method of cardiovascular monitoring should prove useful in human pharmacodynamic studies.

Haemodynamic dose-response effects of UK-52,046 in ischaemic disease with or without impaired left ventricular function

1. The haemodynamic effects of a new cardioselective postsynaptic alpha 1-adrenoceptor antagonist UK-52,046, were evaluated in 25 patients with stable coronary disease, with or without impaired left ventricular function. At rest the haemodynamic effects to two dose-response regimens were determined. In an initial eight patients 0.125, 0.125 and 0.25 micrograms kg-1 were administered peripherally at 15 min intervals; the haemodynamic measurements were determined between 10 to 15 min after each dose. In a further 17 patients, the dose regimen was doubled yielding a cumulative dose-regimen of 0.25, 0.5 and 1.0 micrograms kg-1. The exercise effects were determined by comparison of measurements during 4 min of supine sub-maximal bicycle exercise at a fixed workload before and after drug treatment. 2. At rest, the lower dose regimen of UK-52,046 significantly reduced systemic mean arterial blood pressure (-5 mm Hg; P less than 0.05) and increased cardiac index (+0.2 l min-1 m-2, P less than 0.01). The higher dose regimen of UK-52,046 reduced systemic mean arterial blood pressure (-7 mm Hg; P less than 0.01), pulmonary artery occluded pressure (PAOP) (-2 mm Hg, P less than 0.01) and vascular resistance index (-314 dyn s cm-5 m2; P less than 0.05) with an increase in heart rate (+7%, P less than 0.05) and cardiac index (+0.2 l min-1 m-2, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

An exercise hemodynamic comparison of verapamil, diltiazem, and amlodipine in coronary artery disease

A prospective, randomized study compared the effects of equivalent intravenous doses of three slow calcium-channel blockers (verapamil, diltiazem, and amlodipine) on rest and exercise haemodynamics in 30 ischemic heart disease patients. Following a stable control period during which rest and exercise (supine bicycle) hemodynamics were assessed, equivalent hypotensive doses of each compound were administered over 20 minutes and rest/exercise parameters were assessed 10 minutes later. At rest all agents similarly reduced systemic blood pressure; the fall in systemic vascular resistance and the increase in cardiac indices was ranked: amlodipine greater than diltiazem greater than verapamil. The heart rate increase for amlodopine differed from verapamil and diltiazem (+19.4% vs. +1.5% vs. -7%; p less than 0.01). On exercise, similarly greater falls in the systemic vascular resistance index followed amlodipine, compared with verapamil and diltiazem (p less than 0.05). Only amlodipine significantly reduced the exercise pulmonary artery occlusion pressure (PAOP). Exercise cardiac stroke volume improved after diltiazem and amlodipine. In terms of cardiac performance, both amlodipine and diltiazem produced an improvement, whereas verapamil depressed cardiac pumping activity. Thus, hemodynamic differences between slow-calcium-channel blocking drugs may be demonstrated in humans. These differences would be compatible with a predominant peripheral vascular site of action for amlodipine, in contrast with mixed cardiac and peripheral sites for diltiazem and verapamil.

Haemodynamic and radionuclide effects of amlodipine in coronary artery disease

1. The haemodynamic and radionuclide effects of a new long-acting slow-calcium channel blocking agent, amlodipine, were evaluated in 32 patients with coronary artery disease. 2. Haemodynamic measurements in 24 patients were made at rest and 10 to 15 min after 20 mg i.v. amlodipine. Amlodipine significantly reduced systemic arterial blood pressure and vascular resistance index with an increased heart rate and augmented cardiac index. Cardiac stroke volume index rose and stroke work fell without change in pulmonary artery occluded pressure (PAOP). 3. The exercise effects were determined by comparison of measurements during 4 min of supine bicycle exercise at a fixed workload before and after drug treatment. During dynamic exercise, amlodipine reduced systemic arterial pressure and vascular resistance index. Exercise cardiac index, stroke volume index and heart rate were higher. The left ventricular filling pressure was significantly reduced. 4. Radionuclide parameters were studied in 16 patients at rest and on exercise; ejection fraction was unaltered following amlodipine. 5. Pre-therapy haemodynamic values correlated with response following amlodipine for resting mean blood pressure, systemic vascular resistance and exercise PAOP. 6. Thus, the immediate impact of amlodipine in stable coronary artery disease was to reduce left ventricular afterload and thereby improve cardiac pumping performance.

The treatment of mild to moderate hypertension with ACE inhibitors

The efficacy and safety of quinapril were evaluated in patients with mild to moderate hypertension [sitting diastolic blood pressure (DBP) of 95-115 mm Hg] in seven large, multicenter studies and in one large, single-center study. In double-blind trials, 1,367 patients were treated with quinapril and 820 patients were treated with comparative therapies (enalapril, captopril, chlorthalidone, or placebo). The usual effective dosage of quinapril was 10-40 mg/day, with some patients receiving up to 80 mg/day. Diuretics were added optionally for nonresponders in some studies. Quinapril was equally safe and effective administered either once daily (o.d.) or twice daily and was significantly more effective in lowering blood pressure than was placebo. Quinapril and enalapril administered o.d. were similarly effective in producing clinically and statistically significant reductions in resting blood pressure 24 h after dosing. Quinapril in o.d. doses was as effective as captopril administered two or three times daily. Quinapril was well tolerated; the incidence of adverse events was similar to that for placebo and was comparable to or less than that reported for captopril or enalapril. Quinapril in o.d. doses (10-40 mg/day) is safe and effective as first-line therapy for the treatment of mild to moderate hypertension. Diuretics can be safely added for patients who are not controlled by quinapril alone.

The efficacy of amlodipine in myocardial ischemia

Calcium antagonists are among the most potent and efficacious drugs used in the treatment of angina pectoris. Amlodipine, a new member of this family of dihydropyridines, has a unique pharmacokinetic profile with high bioavailability and an extended period of pharmacodynamic activity. In formal randomized, double-blind, placebo-controlled trials with exercise tests carried out 24 hours after administration, amlodipine was significantly more effective than the placebo and comparable in efficacy with the calcium antagonist diltiazem and the beta-blocking drug nadolol. In addition to extending exercise capacity in patients with angina pectoris, amlodipine significantly reduces ECG evidence of myocardial ischemia. Amlodipine has also been found to be effective in reducing the anginal attack rate in patients with vasospastic angina. From the evidence available, it is concluded that once-daily treatment with amlodipine in the dose range of 5 to 10 mg is effective in improving exercise capacity and reducing anginal attack rate in patients with chronic stable angina pectoris and also those with vasospastic angina.

Nitrate therapy for left ventricular failure complicating acute myocardial infarction: a haemodynamic comparison of intravenous, buccal, and transdermal delivery systems

The haemodynamic effects of three different methods of nitrate administration [intravenous (i.v.) isosorbide dinitrate (ISDN) and buccal and transdermal nitroglycerin (NTG)] were evaluated in 36 patients with acute left ventricular failure due to a recent myocardial infarction. Similar reductions in pulmonary artery occluded pressure (p less than 0.01) followed all three regimens without change in heart rate and cardiac and stroke volume indices. Significant reductions in systemic arterial pressure and vascular resistance followed both ISDN and buccal NTG but not transdermal NTG. A disadvantage of the buccal NTG delivery was an abrupt and, on occasion, inappropriate reduction in blood pressure. The more gradual and controlled reduction of systemic blood pressure with substantial falls in pulmonary artery occluded pressure following ISDN infusion suggest that in the context of myocardial infarction this method of nitrate delivery may have safety advantages; however, when invasive haemodynamic monitoring facilities are not available, transdermal delivery may offer a practical alternative.

Hemodynamic assessment of nicardipine alone and with atenolol in coronary artery disease using a modified echo-Doppler device

We have used a modified noninvasive echo-Doppler cardiac output device, based on the principle of attenuated compensation volume flow, to assess the cardiovascular effects of the slow-calcium antagonist nicardipine in coronary disease. The dose-response effects of 2.5, 5.0 and 10.0 mg intravenous nicardipine were determined in 8 patients with angina. Dose-related decreases were seen in systemic mean arterial pressure (p less than 0.01) after administration of nicardipine. Cardiac pumping indexes were improved, as evident from linear increases in cardiac stroke volume (p less than 0.001), stroke length (p less than 0.01) and time-averaged mean velocity (p less than 0.01). The echo-Doppler device was also used to assess beta-blocking/nicardipine combination therapy in patients with angina. When nicardipine was given after the cardioselective beta blocker atenolol the reduction in heart rate and cardiac output after atenolol was reversed compared with a group that received atenolol followed by placebo. Cardiac performance improved and the 35% reduction in systemic vascular resistance was associated with markedly increased cardiac index (p less than 0.01), augmentation of time-averaged mean velocity (p less than 0.01) and cardiac stroke length (p less than 0.05). These data are consistent with previous invasive studies of nicardipine, either alone or when combined with beta blockade in coronary disease. The data also suggest that nicardipine/beta-blocking combination is safe in patients with coronary heart disease and that the echo-Doppler method of cardiovascular monitoring will prove useful in human pharmacodynamic studies.

Clinical pharmacotherapeutics of doxazosin

Doxazosin is the latest in a series of highly selective postsynaptic alpha 1-adrenoceptor inhibitors. It is readily absorbed, with high bioavailability and a relatively long plasma half-life, neither of which property is influenced by age. This accounts for the prolonged pharmacologic activity of doxazosin following a single oral dose. Its prime pharmacodynamic activity resides in its ability to counter sympathetic vasoconstriction of the systemic arteriolar resistance vessels and venous capacitance system, which enables the drug to target the major pathophysiologic abnormality in hypertension, i.e., the generalized systemic arteriolar constriction. The widespread vasodilation induced by doxazosin relieves both cardiac preload and afterload and, consequently, reduces left ventricular wall stress and myocardial oxygen consumption. In hypertension, doxazosin reduces blood pressure both at rest and during exercise by reduction of systemic vascular resistance without precipitating substantial reflex cardiac stimulation. The effects are maximal on the standing blood pressure between two and four hours after ingestion; due to doxazosin's relatively slow absorption, postural hypotension is infrequent. Its antihypertensive activity is maintained over 24 hours following a single oral dose, and the optimal dose range is 2 to 8 mg once daily. The antihypertensive efficacy of doxazosin has been shown to be comparable with that of other alpha-adrenoceptor inhibitors, beta-blocking drugs, diuretics, calcium antagonists, and angiotensin-converting enzyme inhibitors. In contrast to other conventional antihypertensive drugs, a unique feature of alpha-adrenoceptor-inhibiting drugs, including doxazosin, is their ability to reduce the plasma concentrations of triglycerides, total cholesterol, and low-density lipoprotein cholesterol and to increase high-density lipoprotein cholesterol concentration. This contrasts with the opposite effect on lipid levels induced by hydrochlorothiazide and atenolol seen in comparative studies. Side effects show no predilection for any organ system, and the overall incidence of such effects compares well with those of other commonly used antihypertensive drugs. This unique combination of antihypertensive efficacy and favorable effect on blood lipid levels indicates that once-daily treatment with doxazosin holds considerable promise in the treatment of hypertension, both from the point of view of its antihypertensive efficacy and also from its primary preventative potential.

Therapeutic targets and expectations for the treatment of heart failure

Drug therapy for heart failure holds considerable promise. Direct support of cardiac pumping activity with positive inotropic drugs provides a specific correction for the failing myocardium. Vasodilatation of the systemic arteriolar resistance and venous capacitance systems affords a different but equally rational remedy. Volume and pressure load on the heart is reduced and this augments the pharmacodynamic effects of drugs with positive inotropic activity. For this reason, drugs possessing both pharmacodynamic attributes are an important development in heart failure. The precise clinical targets at which heart failure therapy must be aimed are: (i) relief of symptoms and improvement in quality of life; (ii) reduced risk of morbid events, particularly ventricular arrhythmias; and (iii) extension of survival. Whilst the pathophysiological targets for drug intervention are the same at all stages of the syndrome, expectations of benefit are likely to depend on the stage at which therapy is instituted. In early or mild heart failure, when the patient is not markedly impaired by symptoms, the most that can be expected from treatment is a marginal improvement in quality of life but a major improvement in survival expectancy. In contrast, treatment of severe heart failure may be expected to improve the quality of life substantially by relieving the oppressive symptoms of the advanced syndrome, but only a relatively small increase, if any, in survival. Nevertheless, when the syndrome is terminal, improvement in quality of life carries a clinical priority far in excess of prolonged survival.

Effects of nicorandil on left ventricular hemodynamics and volume at rest and during exercise-induced angina pectoris

The hemodynamic effects of nicorandil (20 mg) were compared with placebo in a double-blind study of 20 patients with angiographically proved coronary artery disease at rest before and 7, 15, 30 and 60 minutes after oral dosing. The impact of the drug on left ventricular (LV) hemodynamics and volume during exercise-induced angina was determined by repeating exercise 60 minutes after drug administration, at the same work load that reliably induced angina during control predrug exercise. At rest, nicorandil reduced all components of systemic arterial pressure without change in cardiac or stroke volume indexes or heart rate. Pulmonary artery occluded pressure was reduced without change in LV ejection fraction or systemic vascular resistance index. Effects were evident at 7 minutes and peaked at 30 minutes with attenuation at 60 minutes. Compared with control supine bicycle exercise, the drug (at 60 minutes) reduced mean systemic arterial pressure and LV filling pressure without change in cardiac stroke volume indexes and heart rate. There was a smaller increase in LV ejection fraction. These data suggested greatest impact on LV function during exercise when substantial decreases in filling pressure occurred at maintained cardiac pumping indexes.

A comparison of the efficacy and safety of quinapril with that of enalapril in the treatment of mild to moderate essential hypertension

This twenty-eight-week double-blind study in patients with mild to moderate essential hypertension showed quinapril (10, 20, and 40 mg/day) to be similarly effective to enalapril at the same doses in producing clinically significant reductions in sitting DBP. Hydrochlorothiazide could be safely added to quinapril therapy in nonresponders. Quinapril and enalapril were well tolerated. Both agents can safely be administered as first-line therapy.

Comparative effects of atenolol and cicloprolol on cardiac performance in coronary heart disease

Cicloprolol is a new cardioselective beta-blocking agent with partial agonist activity (intrinsic sympathomimetic activity, ISA). Its haemodynamic profile was compared with that of atenolol (cardioselective; no ISA) in a comparative dose-response study of 24 ischaemic patients with diminished cardiac reserve. Following a stable control period, equivalent intravenous (i.v.) beta-blocking boluses of atenolol (1, 1, 2, and 4 mg) or cicloprolol (0.025, 0.025, 0.05, and 0.1 mg/kg) were randomly administered and haemodynamics and left ventricular ejection fraction were determined at rest and during bicycle exercise. At rest, atenolol reduced heart rate (HR) and cardiac index; diastolic blood pressure (DBP), systemic vascular resistance index (SVRI), and pulmonary artery occluded pressure (PAOP) increased without change in mean arterial pressure (MAP). Cicloprolol increased left ventricular ejection fraction, reduced its end-diastolic volume, and tended to reduce filling pressure without change in other variables. During exercise, atenolol reduced ejection fraction and increased SVRI; in contrast, cicloprolol did not significantly alter these parameters. Attenuation of exercise tachycardia and cardiac index increase was similar after each agent. Thus, the cardiac performance assessed from left ventricular stroke index or ejection fraction/filling pressure relationships was less depressed after cicloprolol as compared with atenolol. The relevance of such haemodynamic differences to exercise ability or quality of life during sustained therapy warrants examination.

A comparison of doxazosin and enalapril in the treatment of mild and moderate essential hypertension

The antihypertensive efficacy and safety of doxazosin, a selective alpha 1-adrenoceptor antagonist, were compared with that of the angiotensin-converting enzyme inhibitor enalapril in an 18-week double-blind, parallel-group trial. Sixty-seven hypertensive patients entered the three-phase study, which involved a 4-week placebo washout period, a 10-week titration period with doxazosin, 1 to 16 mg, or enalapril, 10 to 40 mg once daily followed by a 4-week maintenance period. The target response was a standing diastolic blood pressure less than or equal to 90 mm Hg. In the 62 efficacy evaluable patients the mean final daily dose of doxazosin was 5.6 mg and 25.5 mg for enalapril. The percentages of therapeutic successes were 74% in the doxazosin- and 81% in the enalapril-treated groups; the proportions in whom standing diastolic blood pressure less than or equal to 90 mm Hg were 55% and 61%, respectively. Both sitting and standing blood pressures were significantly reduced at all visits during the 14-week treatment period in both groups. Twelve patients receiving doxazosin reported 14 adverse events and nine patients administered enalapril reported 19 adverse events; therapy was stopped in three patients in each group because of side effects. The overall assessment of efficacy was excellent or good for 71% of the doxazosin-treated and 67% of the enalapril-treated patients, respectively. Toleration of therapy was excellent or good for 91% of the doxazosin-treated and 88% of the enalapril-treated patients, respectively. No clinically significant changes were observed in the serum lipids, plasma biochemistry, or hematologic profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacotherapeutic stature of doxazosin and its role in coronary risk reduction

In hypertension the primary pathophysiologic abnormality is a generalized increase in the peripheral vascular resistance as a result of concentric narrowing of the systemic arterioles, as a result of alpha 1-receptor stimulation. Such stimulation is attenuated by the selective alpha 1-inhibitor doxazosin. The pharmacologic attributes of doxazosin are translated into direct relaxation of the peripheral arteriolar resistance vessels and venous capacitance system, particularly those with a high alpha-adrenoceptor population. The direct effects of such vascular dilatation are immediately beneficial to the heart in reducing systemic and pulmonary vascular pressures that reduce left ventricular wall stress and myocardial oxygen consumption. In clinical studies doxazosin has been found to have a plasma half-life of 19 to 22 hours, of which a single daily dose is sufficient to control hypertension. The antiatherogenic changes in the blood lipid profile resulting from long-term treatment with doxazosin can also be expected to advance its primary prevention potential in hypertensive patients, which is in marked contrast to the potentially disadvantageous changes in the blood lipid profile that follow treatment with beta-blockers and thiazide diuretics. The therapeutic efficacy of doxazosin has been confirmed, irrespective of hypertension severity, age and race of the patient, or the presence of renal impairment or diabetes mellitus. Its side-effect profile is not substantially different from that of placebo or other antihypertensive drug treatment. Given its unique actions regarding antihypertensive efficacy, together with favorable effects on blood lipids, doxazosin probably holds more promise for the prevention of precocious coronary heart disease in hypertensive patients than any other currently available antihypertensive agent.

Drug therapy of chronic heart failure

Chronic heart failure is an irremediable terminal syndrome. The inability of the heart to pump sufficient blood to meet the demands of metabolically active tissues is aggravated by reflex increases in peripheral vasoconstriction induced by the sympathoadrenal and renin-angiotensin-aldosterone systems. Vasoconstriction is partially attenuated by atrial natriuretic hormone, prostaglandin, and bradykinin. The aim of therapy is to improve the pumping performance of the heart and reduce arterial and venous constriction in the hope that this will reduce symptoms and improve the quality of life. Many drugs achieve such benefits, at least initially. Inotropic drugs increase cardiac pumping activity, and drugs acting directly on arteries and veins improve cardiac function by reducing afterload and preload. ACE inhibitors suppress angiotensin II formation, reducing its vasoconstrictive action, its ability to increase aldosterone secretion and the consequent salt retention and expansion of plasma volume. Since the proportionate role played by various hemodynamic factors in individual patients is unknown, it is likely that most benefit will be achieved by a combined therapeutic approach.

Sympathetic (alpha-beta) or calcium channel blockade for hypertensive myocardial infarction? A haemodynamic comparison of labetalol and nifedipine

The haemodynamic impact of alpha- and beta-adrenoceptor blockade (labetalol) was compared with that of slow-calcium channel blockade (nifedipine) in 32 patients with sustained elevation of systemic arterial pressure (systolic blood pressure greater than 160; diastolic blood pressure greater than 95 mmHg) following a recent myocardial infarction (6-22 h). Patients with normal (pulmonary artery occluded pressure; (PAOP less than 18 mmHg; n = 16) or impaired (PAOP greater than 18 mmHg; n = 16) left ventricular function were randomized to labetalol (1 mg/kg i.v. 15 min) or nifedipine (20 mg sublingually) and haemodynamic profile was measured over 2 h. Both drugs equally reduced mean systemic arterial pressure (P less than 0.01 versus pretreatment control), and presumably left ventricular afterload; however, the heart rate (P less than 0.01) and cardiac index (P less than 0.01) increased after nifedipine, contrasting with reductions in both variables following labetalol (P less than 0.01). The elevated left ventricular filling pressure was reduced by both labetalol (P less than 0.05) and nifedipine (P less than 0.01) but the reduction was greater following nifedipine (-2 mmHg versus -5 mmHg, P less than 0.05). Thus both compounds were equally effective hypotensive agents. Labetalol consistently reduced cardiac stroke work and double product, important determinants of myocardial oxygen requirements; however, nifedipine afforded some improvement in cardiac performance in patients with left ventricular dysfunction.

Celiprolol in hypertension

Celiprolol is a third-generation, beta-adrenoceptor antagonist with ancillary pharmacologic properties that are potentially advantageous in the treatment of hypertension. Celiprolol provides 24-hour control of blood pressure and in formal clinical trials has been found superior to a placebo and of equal efficacy to other commonly used beta-blocking drugs. It has also been found to be equally as effective as enalapril in lowering the resting blood pressure and superior in controlling the increases in blood pressure and heart rate during exercise. Celiprolol is known to exert a beneficial effect on the atheroprotective components of the risk factors for coronary heart disease, such as cholesterol triglyceride, and fibrinogen. Therefore the primary attributes of beta-blockade are uniquely advanced by celiprolol's ancillary pharmacologic activities.

Circulatory effects of intravenous and oral atenolol in acute myocardial infarction

The hemodynamic dose-response effects of intravenous (0.05 and 0.10 mg/kg) and oral (50 and 100 mg) atenolol were compared in a randomized between-group study of 24 men within seventeen hours of an acute uncomplicated myocardial infarction; 6 subjects were evaluated in each of the four groups. Hemodynamic variables were determined over a one-hour control period, following which the randomized dose of atenolol was administered and measurements repeated at 15 (intravenous therapy only), 30, 60, 90, 120, 180, 240, 300, and 360 minutes. The peak hemodynamic effect was similar and independent of either the dosage or route of administration. In all groups atenolol reduced heart rate and cardiac and stroke volume indices. The pulmonary artery occluded pressure and systemic vascular resistance index were transiently increased. Mean arterial pressure was significantly reduced only in the oral group with the highest pretreatment pressure. Maximum changes developed between fifteen and thirty minutes after intravenous dosing and between two and three hours after oral dosing. However, substantial reductions in cardiac index (-0.6 L/min/m2; p less than 0.05) were already achieved at sixty minutes following oral dosing. The duration of pharmacodynamic activity was for two to three hours following intravenous and for the study duration (four to six hours) after oral dosing. These data confirm the hemodynamic safety of atenolol after acute myocardial infarction.

Hemodynamic comparison of dopexamine hydrochloride and dopamine in ischemic left ventricular dysfunction

The hemodynamic dose-response effects of intravenous dopexamine hydrochloride (0.5 to 2.0 micrograms/kg/min) have been compared with dopamine (2.5 to 10 micrograms/kg/min) in 12 patients with ischemic left ventricular dysfunction in an open randomized crossover study. Both drugs increased cardiac output and decreased systemic vascular resistance. Dopexamine hydrochloride appeared to increase heart rate more than dopamine although this did not reach statistical significance. Dopexamine hydrochloride produced small increases in systolic and decreases in diastolic blood pressure, whereas dopamine had a biphasic effect resulting in a decrease in mean blood pressure at low doses and an increase at the highest dose studied. With increasing dosage, there was a trend toward more vasodilator activity with dopexamine hydrochloride than with dopamine. Dopexamine hydrochloride produced fewer adverse effects than dopamine.

Cardiovascular consequences of heart failure

The cardiac and reflex neuroendocrine consequences of heart failure are reviewed. The mechanisms responsible for the many neuroendocrine reflexes that result as a consequence of heart failure are considered particularly in relation to their pathophysiological interactions. The lack of knowledge regarding quantitative changes occurring in the various circulatory reflexes activated by heart failure and the paucity of knowledge of the immediate and long-term effects of pharmacotherapeutic interventions on these reflexes are highlighted.

Celiprolol and the heart

The introduction of beta-adrenoceptor antagonists was a major advance in the treatment of hypertension and coronary artery disease. However, nonselective beta blockade carries distinct circulatory disadvantages, which accounts for the search for an "ideal" beta-blocking drug for use in this extensive therapeutic field. It is possible to define the desirable cardiodynamic profile of a beta-blocking drug. How far does celiprolol meet this function? What questions should we address in attempting to evaluate the effects of celiprolol on the heart? In contrast to propranolol, in the normal heart, celiprolol does not depress left ventricular pumping function. There is little information on the effects of celiprolol on left ventricular function in the hypertensive patient. However, we now know that most patients with hypertension already have advancing coronary artery disease. It is reasonable, therefore, to examine the effects of celiprolol on left ventricular function in patients with coronary disease because these can not only be used to evaluate the possible efficacy of the drug in patients with angina pectoris, but also to extrapolate to their clinical effectiveness in most patients with hypertension. Celiprolol does not depress left ventricular pumping function at rest or during exercise, in contrast to other beta-adrenoceptor antagonists that reduce both heart rate and left ventricular activity. Moreover, celiprolol possesses anti-ischemic properties equivalent to those of atenolol. It does not appear to aggravate the atherogenic profile of the lipids as much as some other cardioselective beta-blocking drugs.(ABSTRACT TRUNCATED AT 250 WORDS)