Comparative effects of oral acebutolol and propranolol at rest and during exercise in ischemic heart disease: double-blind placebo crossover study utilizing radionuclide ventriculography

The effect of atenolol on the left ventricular performance in patients with angina pectoris measured with isotope technique

Working capacity, left ventricular ejection fraction (EF), stroke volume and the phase of the left ventricular contraction were tested before and after 3 weeks of atenolol treatment in 14 patients with angina pectoris and coronary insufficiency diagnosed by thallium tomography. Eight patients (group A) increased their EF during exercise and six patients (group B) showed a decrease in EF when tested with placebo. When treated with atenolol the changes in EF during exercise were reversed in the two groups. Group B increased and group A decreased their EF. Atenolol caused an increase in working capacity in group B, but not in group A. In both groups atenolol caused an increased stroke volume and a decreased phase deviation at rest, while no significant volume changes or phase changes occurred during exercise. These results indicate that atenolol treatment had the most marked effect in patients with the most pronounced disease.

Amlodipine reduces myocardial ischaemia during exercise without compromising left ventricular function in patients with silent ischaemia: a randomised, double-blind, placebo-controlled study

BACKGROUND

Left ventricular systolic function is reduced during episodes of silent ischaemia in patients with coronary artery disease (CAD). In most normal subjects left ventricular ejection fraction (LVEF) increases at least 5% during exercise whereas LVEF often remains unchanged or decreases in patients with CAD. The anti-ischaemic effect of calcium antagonists is well documented including a capability to reduce exercise-induced electrocardiographic ST-depressions, whereas the effect of these drugs on LV volume changes during exercise in patients with silent ischaemia is unknown.

AIM

The aim of this study was to evaluate the effect of amlodipine on rest and exercise LVEF in patients with silent ischaemia.

METHODS

Twenty-one patients completed a double-blind placebo-controlled cross-over study. Conventional exercise test and radionuclide cardiographies during exercise were used for determining haemodynamic parameters.

RESULTS

Exercise-induced electrocardiographic ST-depressions were reduced in 83% of the patients having ST-deviations during placebo even though 10 patients were already treated with a beta-blocker. Amlodipine did not affect left ventricular systolic function compared to placebo, neither at rest nor during exercise.

CONCLUSION

The results indicated that amlodipine is a safe anti-ischaemic drug in patients with silent ischaemia concerning cardiac function.

Metoprolol abolishes exercise-induced left ventricular dysfunction in patients with silent ischemia

Left ventricular systolic function is reduced during episodes of silent ischemia in patients with coronary artery disease (CAD). Left ventricular ejection fraction (LVEF) is increased at least 5 absolute percent during exercise in most normal subjects; however, in patients with CAD, LVEF often remains unchanged or decreases. The anti-ischemic effect of beta-adrenergic receptor blockade is well documented, including a reduction of exercise-induced electrocardiographic ST depressions; however, the effect of these drugs on left ventricular volume changes during exercise in patients with silent ischemia is unknown. The aim of this study was to evaluate the effect of a cardio-selective beta-blocking agent, metoprolol, on rest and exercise LVEF in patients with silent ischemia, using radionuclide cardiography. Fifteen patients with silent ischemia completed a double-blind, placebo-controlled crossover study at rest and during submaximal exercise. LVEF remained unchanged during exercise in the placebo phase (56% to 58%; p = NS), but even though LVEF tended to decrease 56% during rest after metoprolol versus 52% after placebo (p = NS), the LVEF increase from rest to exercise resembled a normal LVEF response, 52% to 58% (p = 0.005). Exercise-induced electrocardiographic ST depressions were also reduced during metoprolol treatment. In patients with silent ischemia, the exercise-induced change in LVEF rises significantly during metoprolol treatment. The mechanism may be a reduction in myocardial ischemia as indicated by a reduction in ischemic electrocardiographic findings.

Effect of xamoterol on exercise capacity and left ventricular function in angina pectoris and in dilated cardiomyopathy

The present study evaluates the effect of the beta 1 partial agonist xamoterol in patients with coronary artery disease compared to the effect in patients with dilated cardiomyopathy. Nineteen patients with angina pectoris and nine patients with dilated cardiomyopathy received xamoterol 200 mg b.i.d. for 4 weeks in a placebo-controlled double-blind study. The effect was evaluated with a standardized exercise test and radionuclide angiocardiography with determination of global and regional ejection fraction. At rest xamoterol caused no significant changes among the angina patients while global and regional ejection fraction increased among the cardiomyopathy patients. During exercise, when the drug exerts a beta 1-antagonist effect, xamoterol increased the exercise performance among the angina pectoris patients. Fourteen out of 19 patients with angina pectoris were unable to increase their ejection fraction from rest to work due to coronary ischaemia. These 14 patients improved their global ejection fraction during work after xamoterol treatment.

Left ventricular function and beta-blockers: does intrinsic sympathomimetic activity have any influence during chronic therapy?

A study comparing the chronic effects of propranolol (n = 21) and pindolol (n = 19) on male patients with stable angina pectoris was performed. Left ventricular function was assessed by serial radionuclide ventriculography. Radionuclide ventriculography was performed at rest and during cold pressor test. Both drugs improved symptoms of angina pectoris by at least one division of the New York Heart Association classification. Cold pressor testing caused increases in heart rate and blood pressure in both groups throughout the study. At rest, pretreatment ejection fraction was similar in both groups. During propranolol treatment this rose sequentially from 49% to 55% at 26 weeks. No change in the resting ejection fraction occurred in those taking pindolol. The difference in response between the groups reached significance at 26 weeks. In those with subnormal left ventricular ejection fraction (less than 50%), resting ejection fraction improved significantly throughout treatment with propranolol rising from a basal value of 39% to 51% at 26 weeks. In comparison, pindolol caused no significant change. There is no apparent advantage to intrinsic sympathomimetic activity in terms of preservation or improvement of left ventricular performance in patients with stable angina pectoris prescribed beta-blockers for extended periods of time.

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.