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Biomedical subjects

S Oram

Publications and source records attributed to S Oram.

At least 19 recordsLinked to original sources

Effect of nifedipine on exercise tolerance in angina pectoris.

Nifedipine is a new antianginal drug, the calcium-antagonistic inhibitory action on excitation-contraction coupling apparently being so pronounced that, in therapeutic dosage, all other pharmacological properties are negligible. Its effect on exercise tolerance in angina was assessed by an exercise study involving 14 patients: single-stage exercise tests were chosen and the advantages of this are given. Our results suggest that the onset of action occurs after about 20 minutes, reaches a peak of activity at approximately one-half to two hours, and some effect may still be present at three hours. There was a significant improvement in exercise times with a mean rise of 50 per cent over placebo.

Adult

Asymmetric septal hypertrophy and propranolol treatment in a case of Ullrich-Noonan syndrome.

A 4-year-old boy with the Ullrich-Noonan syndrome is described. Asymmetric septal hypertrophy was diagnosed by echocardiography and confirmed at cardiac catheterisation. The aortic subvalvar gradient was reduced from 56 mmHg to 10 mmHg with intravenous propranolol. Relatives of patients with the syndrome should be screened by echocardiography in the hope that the early detection of asymmetric septal hypertrophy and its treatment with propranolol may reduce the likelihood of sudden death.

Aortic Valve Stenosis

Diagnosis of coronary artery disease by estimation of coronary sinus lactate.

In an attempt to assess the value of coronary sinus lactate estimation before and during atrial pacing for the diagnosis of obstructive coronary artery disease, 70 patients with angina were investigated in this way and by selective coronary arteriography. Thirty-five had radiologically normal coronary arteries and 35 had coronary artery disease. When the change in coronary arteriovenous lactate difference was less than 0.09 mmol/l (0.8 mg/100 ml) between the control and the peak atrial pacing sample, the coronary arteries were normal except in one patient who had distal disease of a single vessel. When the change was greater than 0.22 mmol/l (2.0 mg/100 ml) coronary artery disease was always found, and when the change was greater than 0.39 mmol/l (3.5 mg/100 ml) there was always disease of two or three vessels. Unfortunately, the presence or absence of coronary artery disease could not be predicted when the change fell between 0.09 and 0.22 mmol/l (0.8 and 2.0 mg/100 ml). Estimation of coronary sinus lactate before and during atrial pacing can thus frequently distinguish patients with normal coronary arteries from those with coronary artery disease.

Adult

Occlusion of the subclavian vein associated with cephalic vein pacemaker electrodes.

Thrombosis and occlusion of major veins have been described following the use of transvenous pacing electrodes for the establishment of permanent cardiac pacing. The frequency of such complications is, however, not well known. A series of 125 patients was therefore reviewed, all of whom had been paced with permanent transvenous electrodes through a cephalic vein. There was clinical and venographic evidence of subclavian vein occlusion in only 3 of these patients. A further 20 of these patients were also subjected to venography and showed no radiographic evidence of venous occlusion although minor thrombosis associated with the pacemaker electrode was found in one patient. It is concluded that the convenience of using the cephalic vein as a route for the insertion of transvenous pacing electrodes outweighs the small risk of major venous occlusion.

Adult

Reassessment of failed beta-blocker treatment in angina pectoris by peak-exercise heart rate measurements.

Twenty-one patients with angina pectoris were treated with adrenergic beta-receptor antagonists. Previously the resting heart rate had been used as a guide to treatment, a reduction in the rate to 55-60 beats/min without symptomatic improvement indicating failure of medical treatment. These patients were re-evaluated before coronary arteriography using the peak-exercise heart rate as an index of adrenergic beta-receptor antagonism. The dose of beta-blocking drugs was increased to produce a peak-exercise heart rate of less than 100 beats/min or a consistent rate of 100-125 beats/min which would not lessen in spite of progressive dose increments. The resting heart rate was ignored. On these criteria 15 patients previously considered to have responded inadequately to beta-blockade responded satisfactorily and were therefore removed from the waiting list for coronary arteriography. They all remained well up to two years later. Six patients failed to respond and had coronary arteriography with a view to surgical treatment. Reliance on the resting heart rate as the index of optimum adrenergic beta-receptor antagonism is likely to lead to premature or unnecessary referral for surgery; the failure of beta-blockade in the treatment of angina pectoris can be determined simply and accurately by using peak-exercise heart rate.

Adrenergic beta-Antagonists

Modification by propranolol of cardiovascular effects of induced hypoglycaemia.

The cardiovascular effects of hypoglycaemia, with and without beta-blockade, were compared in fourteen healthy men. Eight received insulin alone, and eight, including two of the original insulin-only group, were given propranolol and insulin. In the insulin-group the period of hypoglycaemia was associated with an increase in heart-rate and a fall in diastolic blood-pressure. In the propranolol-insulin group there was a significant fall in heart-rate in most subjects and an increase in diastolic pressure. Typical S-T/T changes occurred in the insulin-group but in none of the propranolol-insulin group. Hypertension in diabetics prone to hypoglycaemia attacks should not be treated with beta-blockers because these drugs may cause a sharp rise in blood-pressure in such patients.

Arrhythmia, Sinus

Double-blind comparison of tolamolol, propranolol, practolol, and placebo in the treatment of angina pectoris.

Forty-two patients with angina pectoris have completed a randomized, double-blind trial comparing tolamolol 100 mg and 200 mg with propranolol 80 mg, practolol 100 mg, and placebo, all given three times a day. Tolamolol 200 mg thrice daily was found to be equivalent to propranolol 80 mg thrice daily in anti-anginal efficacy. Anginal attack rates and trinitrin consumption were significantly reduced by all active treatments as compared with the placebo but tolamolol and propranolol were the most effective. Tolamolol 200 mg thrice daily was most effective in reducing blood pressure, while propranolol was most effective in reducing the resting heart rate. All treatments except the placebo significantly increased the amount of exercise which could be performed before angina appeared (exercise work), while tolamolol 200 mg thrice daily significantly reduced Robinson's index when compared with all other active agents. The degree of S-T segment depression induced by exercise was significantly lessened by both tolamolol and propranolol but not by practolol or placebo. There was no difference in patient preference between tolamolol and propranolol but tolamolol at both dose levels was preferred to practolol. Both tolamolol and propranolol are potent adrenergic beta-receptor antagonists and equal in anti-anginal efficacy but tolamolol has the advantage of being cardioselective. It is superior to practolol.

Adult

Double-blind evaluation of verapamil, propranolol, and isosorbide dinitrate against a placebo in the treatment of angina pectoris.

In the treatment of angina pectoris a double-blind evaluation of verapamil (Cordilox) at two dose levels-namely, 80 mg thrice daily and 120 mg thrice daily-propranolol (Inderal) 100 mg thrice daily, and isosorbide dinitrate (Vascardin) 20 mg thrice daily has been made against a placebo. The assessment was based on relief from daily attacks of angina on effort and the response to a whole-body exercise test. We can find no statistically significant difference between the effects of verapamil (120 mg three times a day) and propranolol (100 mg three times a day) in the treatment of angina of effort. Both of these preparations are more effective than a placebo both in the reduction of daily attacks (P < 0.01) and in the prolongation of exercise test (P < 0.05). Isosorbide dinitrate (20 mg three times a day) appears to be no more effective than a placebo in the treatment of angina on effort, but 14 out of 32 patients experienced headache of such severity that even when the dose was reduced to 10 mg thrice daily this drug therapy had to be withdrawn. Both propranolol (100 mg three times a day) and verapamil (120 mg three times a day) had a significant lowering effect on the diastolic blood pressure as measured with the patient standing (P < 0.01).

Adult