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Biomedical subjects

A P Rae

Publications and source records attributed to A P Rae.

61 records · Page 4Linked to original sources

Comparison of three adrenoreceptor blocking agents in patients with cirrhosis and portal hypertension.

The effects of different types of adrenoreceptor blocking agents on portal venous pressure were studied in patients with cirrhosis and portal hypertension. Oral atenolol (selective beta 1 blocker), propranolol (non-selective beta 1 and beta 2 blocker), and prazosin (alpha blocker) were compared in three groups of eight patients. Haemodynamic measurements were made before and after two or three and eight weeks of therapy. The dose of beta blockers was sufficient to reduce the exercise heart rate by more than 25%. Propranolol and prazosin produced a sustained reduction in the mean portohepatic venous pressure gradient of the order of 25% and 18% respectively. The cardiac index was significantly reduced by propranolol but not altered by prazosin. Atenolol produced an early reduction in portohepatic venous pressure which, although not sustained, showed a good correlation with reduction in cardiac index. No such relationship was found with propranolol. All three drugs were well tolerated by these patients with advanced cirrhosis. Therefore propranolol and prazosin have proved to be effective agents for the reduction of portal venous pressure.

Atenolol↗

Interpreting an ECG. Atrial premature complex.

When APCs are symptomatic or are a potential trigger for supraventricular tachycardia or atrial fibrillation, suppressive therapy with beta-blocking drugs or type I antiarrhythmic agents is indicated. If APCs are infrequent and produce no symptoms, attention to possible provocative factors--excess tobacco or caffeine, or drugs (eg, sympathomimetic amines, monoamine oxidase inhibitors, tricyclic antidepressants)--is all that is required.

Adrenergic beta-Antagonists↗

The clinical use of inotropes in cardiac failure: dopamine, dobutamine, prenalterol and pirbuterol.

The impaired cardiac performance in patients with congestive cardiac failure may be improved by the introduction of inotropic therapy. Dopamine and dobutamine are both potent cardiac stimulants although their haemodynamic profile is different. Dobutamine would appear to be the more appropriate choice in cardiac failure because of the additional benefit of preload reduction although in the context of severe hypotension dopamine would be preferred. The need for intravenous administration, however, limits their clinical application. In acute studies, the oral agents prenalterol and pirbuterol, are effective in improving myocardial function; pirbuterol mainly due to peripheral vasodilatation and afterload reduction. There are few chronic studies but confirmation of sustained haemodynamic improvement is lacking. This could be due, either to the inexorable deterioration in cardiac function or to a reduction in the beta receptor population available for catecholamine stimulation.

Catecholamines↗

Non-invasive cardiovascular assessment of indapamide in patients with essential hypertension.

The antihypertensive effect and a non-invasive cardiovascular assessment of indapamide in patients with idiopathic hypertension have been investigated in an uncontrolled study. Indapamide was found to be an effective antihypertensive agent in a dose of 2.5 mg per day with a mean fall in blood pressure of 25/18 mmHg. Apart from the development of impotence in one patient, no side effects were encountered. Its effect on heart rate and cardiac output suggest that vasodilatation may contribute to its mode of action. Exercise performance is well maintained and cardiac performance appears to improve when blood pressure is lowered with this drug.

Adult↗

A prospective randomized trial of tocainide in patients following myocardial infarction.

One hundred forty-six patients with recent acute myocardial infarction were grouped at random into those treated with tocainide, an oral analogue of lignocaine, or placebo and followed up for 6 months. In addition to standard investigations, a 24-hour ambulatory taped ECG recording was obtained prior to randomization and thereafter at 2, 8, 16, and 24 hours after discharge. The ECGs were analyzed by means of an automated, computerized reporting system. Forty-two patients had significant ventricular arrhythmias, 10 of whom had effective plasma levels of tocainide compared with 27 patients on placebo (P < 0.005). In the placebo patients with increasing mobilization there was a consistent rise in the number of ventricular ectopic beats per day. There was no such increase in the tocainide patients (P < 0.01). Side effects were few and the incidence of central nervous system side effects was similar in both the tocainide and placebo groups. There was no conclusive evidence of myocardial depression, heart rate and blood pressure being unchanged over the 6-month period. Although ventricular arrhythmias were suppressed, the number of patients in the study was too small to draw conclusions regarding the mortality rate.

Anilides↗

Haemodynamic effects of prenalterol in patients with coronary heart disease.

The haemodynamic effects of prenalterol, a new selective beta-1 adrenoreceptor agonist, have been studied in patients with coronary heart disease. The drug was administered intravenously in a dosage of 0.5 to 2.5 micrograms/kg body weight to 20 patients undergoing coronary angiography and to 10 patients with a recent myocardial infarction, who had clinical evidence of left ventricular dysfunction. Left ventricular performance was enhanced in both groups of patients--left ventricular dP/dt (max) increased by 33 per cent and the systolic time intervals, pre-ejection period, and the ratio of pre-ejection period and left ventricular ejection shortened by 28 and 21 per cent, respectively. Cardiac output and stroke volume increased with no change in heart rate nor in left ventricular filling pressure. These results indicate that prenalterol enhances the contractile state of the myocardium without altering heart rate, and suggest that prenalterol could be of value in the management of patients with coronary heart disease, who have impaired left ventricular function.

Adrenergic beta-Agonists↗