Ocular reaction to propranolol and resolution on continued treatment with a different beta-blocking drug

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Clinical and hemodynamic results of mitral valve replacement with autologous fascia lata grafts. Studies in patients with competent prostheses

Nine patients with severe mitral disease were studied before and six months after mitral valve replacement with a three-cusp stented prosthesis using fresh autologous fascia lata tissue. Only patients in whom there was no auscultatory and angiographic evidence of incompetence of the replaced valve were selected for restudy. All patients claimed a marked improvement in their exercise capacity after operation and there was a significant reduction in radiographic heart size. The cardiac output at rest and the response to exercise were both reduced before operation and were unchanged after valve replacement. The elevated pulmonary arterial and wedge pressures were significantly reduced after operation in all patients both at rest and during exercise, but in no instance were the postoperative exercise values within normal limits. Left ventricular end-diastolic pressure was within normal limits at rest and during exercise in all patients after valve replacement but the average pressure gradient across the fascia lata valve was 6+/-1 mm Hg at rest and 18+/-3 mm Hg during exercise. These findings indicate that altough replacement of the diseased mitral valve with a competent fascia lata prosthesis afforded substantial symptomatic relief, reduction of cardiac enlargement and a lowering of the pulmonary vascular pressures, this artificial valve offered a significant obstruction to left ventricular diastolic filling, particularly during exercise.

Localization of left ventricular ischaemia in angina pectoris by cineangiography during exercise

Cineangiography of the left ventricle during exercise has been used in an attempt to define the area of ischaemic myocardium in patients suffering from angina pectoris in whom coronary artery surgery was contemplated. A correlation was established between the site of coronary artery obstruction and the area of abnormal myocardial contraction. This method of localization of regional left ventricular ischaemia may furnish useful diagnostic information when coronary reconstructive surgery is contemplated in patients with exercise-induced angina pectoris.

A comparative study of the activity of beta-adrenoceptor antagonists in man

1. In healthy subjects the plasma concentration of unchanged drug, heart rate response to excerise and attenuation of isoprenaline tachycardia were maximal at one hour after ingestion of a range of doses of propranolol, oxprenolol, practolol, tolamolol, atenolol and metoprolol. 2. There was a within-drug relationship between plasma concentration of unchanged drug and the attenuation of exercise and iosprenaline tachycardia. There was no similar between-drug relationship. 3. There was a similar exponential relationship between oral dose and reduction of exercise tachycardia for all six drugs. 4. The linear relationship between oral dose and antagonism of infused isoprenaline was significantly greater for oxprenolol and propranolol than for the other four drugs. 5. "Cardioselective" activity was the only ancillary pharmacological property which differentiated the activity of these drugs in normal subjects.

Different effects of adrenergic beta-receptor blockade on heart rate response to mental stress, catecholamines, and exercise

The magnitude and duration of effect of a single 40-mg oral tablet of oxprenolol on the tachycardias associated with motor-car driving, isoprenaline infusion, and walking were compared against placebo in six normal people by a double-blind study. The tachycardias due to driving and isoprenaline were both conspicuousy reduced for over eight hours; the magnitude and duration of the reduction in exercise tachycardia was substantially less. Thus relatively small doses of beta-receptor antagonists will suppress the increase in heart rate induced by mental stress or catecholamines with relatively little effect on the response to everyday exercise. Possibly smaller doses of these drugs would relieve emotionally-induced anginal pain and tachycardia.

Comparison of adrenergic beta-receptor antagonists in angina pectoris

The symptomatic, electrocardiographic, and circulatory effects of intravenous and oral preparations of propranolol, oxprenolol, and practolol were compared in 16 patients with uncomplicated angina pectoris precipitated by exertion. The method of study included treadmill exercise, double-blind assessment, single-blind analysis, with placebo control and randomized serial comparison of each drug in each patient. The doses used were selected to give the same near-maximum suppression of the heart rate response to exercise. The symptomatic, electrocardiographic, and circulatory response of each patient to both preparations of each of the three drugs was similar. Exercise tolerance was increased in two-thirds, unchanged in one-sixth, and significantly worsened in one-sixth of the studies. Electrocardiographic evidence of myocardial ischaemia was conspicuously reduced by all three drugs in most studies irrespective of their symptomatic effects. Though the exclusive choice of patients, the single dose design of the trial, and the treadmill method of assessment limit the general application of these results, they do clearly indicate that in doses that induce equal suppression of the exercise heart rate these three drugs have similar distinct anti-anginal activity. Their ancillary pharmacological properties are probably of little importance in this respect. Equally, the similarity in the symptomatic, circulatory, and electrocardiographic response to the intravenous and oral preparations suggests that metabolic breakdown products are probably of therapeutic importance only in so far as they antagonize beta-receptor activity.

Effect of ouabain on insulin secretion in man

1. The effect of an intravenous infusion of ouabain 0·25 μg min−1 kg−1 for 1 h on plasma insulin and blood glucose concentrations in peripheral venous blood and on urinary excretion of catecholamines was studied in six normal adult males. Ouabain had no effect on insulin and glucose concentrations but resulted in a significant decrease in urinary catecholamine excretion.

2. The effect of a single intravenous injection of 001 mg of ouabain/kg on the response of insulin secretion to intravenous tolbutamide was studied in four normal adult males. Ouabain had no significant effect on the increase of plasma insulin which followed tolbutamide.

3. These results indicate that improvement in insulin secretion observed during digitalis-induced remission in heart failure is probably due to the improved circulatory state of the patient and not to a direct insulin secretogogue effect.

4. The mechanisms responsible for decreased catecholamine excretion after ouabain in normal man are unexplained.

Comparison of adrenergic beta-blocking drugs in angina pectoris

The symptomatic, electrocardiographic, and haemodynamic effects of two adrenergic beta-blocking drugs, oxprenolol and propranolol, have been compared in equipotent intravenous doses in six patients with uncomplicated angina pectoris during treadmill exercise. The method of comparison included double-blind assessment and analysis with placebo control and randomized serial comparison in each patient. Both drugs produced an equal amelioration in symptoms in most of the patients. This was closely correlated with improvement in the electrocardiographic changes and a significant reduction in the exercising heart rate and systemic arterial pressure. This method of double-blind combined subjective and objective assessment carries distinct advantages in the comparative assessment of drug treatments in angina pectoris.

Autonomic control of insulin secretion and the treatment of heart failure

To investigate the role of the autonomic nervous system in controlling insulin secretion 13 normal subjects and 5 patients with heart failure underwent insulin secretion tests. Alpha-adrenergic stimulation and beta-receptor blockade significantly depressed the secretion of insulin in response to intravenous tolbutamide in normal subjects, while both alpha-blockade and beta-stimulation significantly increased the insulin secretion response in both normal subjects and patients in heart failure. Parasympathetic stimulation and blockade had no significant effect on the insulin secretion response. These findings suggest that drugs that block the alpha-adrenergic receptors or stimulate the beta-adrenergic receptors by their ability to counteract the insulin suppression resulting from increased sympathetic nervous activity may play a vital metabolic part in the deranged metabolism of the failing heart in addition to their direct haemodynamic benefits.

Insulin secretion in heart failure

Insulin secretion tests were carried out before and after treatment in patients with severe congestive heart failure. Before treatment the plasma insulin level and the insulin secretion response to intravenous tolbutamide were significantly reduced in all patients. In patients who made a good clinical recovery the plasma insulin level and the insulin secretion response were significantly improved. Patients who had a poor response to medical treatment showed little improvement in their insulin secretion test. This suppression of insulin secretion is probably due to the reduced blood flow to the pancreas together with a high level of circulating catecholamines.

Bretylium tosylate in prevention of cardiac dysrhythmias after myocardial infarction

The prophylactic value of parenterally administered bretylium tosylate against the onset of dysrhythmias after acute myocardial infarction has been assessed by a controlled trial in 101 male patients. Bretylium significantly reduced the incidence of supraventricular dysrhythmias but was without significant effect on the incidence of ventricular dysrhythmias. The only serious side-effect of the drug was hypotension which occurred in one-third of the patients. It is concluded that prophylactic treatment of patients suffering from uncomplicated myocardial infarction with parenteral bretylium tosylate probably does not confer sufficient clinical benefit to warrant its recommendation for preventative use in this disease.

Autologous fascia lata for heart valve replacement

To obviate the drawbacks of prosthetic devices and in search of a better substitute for diseased heart valves a technique of using autologous fascia lata grafts attached to a support frame was developed. The technique of preparing mounted fascia lata grafts is briefly outlined and their surgical implantation into the mitral, tricuspid, and aortic areas is described. Since April 1969, 83 fascial grafts have been inserted into 76 patients with very good immediate and short-term results. Ten patients succumbed within the operative period. None of these deaths was due to failure of the graft per se. Thromboembolic manifestations have been completely absent although anticoagulants were not used. All sixty-six survivors are very much improved. Data concerning the structure and function of fascia are presented and the experimental and clinical use of fascia lata in extracardiac and cardiac surgery is reviewed. The use of autologous, living, fascia lata valves is considered to be a better approach for heart valve replacement because autologous fascia maintains its structure unchanged after transplantation and, being under mechanical stimulation, it retains its functional properties.

Insulin secretion in cardiogenic shock

A nearly complete suppression of insulin secretion was observed in four patients in circulatory shock following acute myocardial infarction. This may be due to intense sympathetic activity and raised catecholamine excretion associated with shock.