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Biomedical subjects

D Hunt

Publications and source records attributed to D Hunt.

At least 181 records · Page 10Linked to original sources
PubMed1978

The prognostic value of the HV interval in patients with acute myocardial infarction and bundle branch block.

HV intervals were measured in 42 of 119 patients in the acute phase of myocardial infarction associated with bundle branch block (BBB). The mean HV intervals of patients with right, left and incomplete bilateral BBB were similar. The hospital and subsequent mortality of patients with prolonged HV intervals did not differ significantly from that of patients with normal HV intervals. The HV interval appeared to remain stable over the following months in most patients in whom it was remeasured. We conclude that the HV interval cannot be used to select patients who might benefit from prophylactic long term pacing.

Bundle-Branch Block↗
PubMed1978

Electrophysiology of disopyramide in man.

The electrophysiological effects of an intravenous dose of disopyramide phosphate (2 mg per kg body weight) were studied in 17 patients. Studies were performed with the patients fasting, unpremedicated, and off all medication for three days. Blood samples for estimation of serum levels of disopyramide were collected in 15 of these patients. The effects of intravenous disopyramide were maximal at five minutes, less marked at 20 minutes, and largely gone by 30 minutes after administration of the drug. Sinus cycle length and corrected sinus node recovery time were shortened significantly. No index of atrioventricular nodal function was significantly changed. Both atrial and ventricular effective refractory periods were significantly prolonged. Further impairment of intraventricular conduction occurred in six patients with bundle branch block on electrocardiogram or prolonged HV interval. In one of two patients with Wolff-Parkinson-White syndrome, the bypass effective refractory period was prolonged. These electrophysiological changes are similar to quinidine and quinidine like drugs. It is recommended that disopyramide should be used cautiously in patients with evidence of His Purkinje system disease since it may lead to higher degrees of intraventricular block.

Adolescent↗
PubMed1978

Effect on survival after myocardial infarction of long-term treatment with phenytoin.

A prospective, randomised, open trial was performed in 150 patients to test for any beneficial effects on 2-year mortality of long-term antiarrhythmic therapy with phenytoin in patients with acute myocardial infarction. Patients were stratified according to age, sex, past history of myocardial infarction, and the presence of absence of electrical or mechanical complications in the course of acute infarction. They were then randomised to treatment or control groups (74 v. 76). The former received phenytoin in doses aimed at maintaining plasma phenytoin levels between 40 and 80 mumol/litre. All patients entered the study before discharge from the coronary care ward. Plasma phenytoin levels were in the therapeutic range in between 51 and 75 per cent of subjects at any follow up visit. There were 19 withdrawals from the treatment group, 10 of which were the result of side effects. There were 5 withdrawals from the control group. According to the original intention to treat, there were 18 deaths at 2 years in the treatment group and 14 deaths in the control group. There was no reduction in the incidence of instantaneous or sudden deaths. Deaths on treatment were not associated with a low phenytoin plasma level. Phenytoin treatment showed no beneficial effects on mortality and was associated with a high incidence of side effects.

Adult↗
PubMed1978

Effects of atrial fibrillation on prognosis of acute myocardial infarction.

Nine hundred and sixty-nine coronary care patients with acute myocardial infarction were followed for one year. Atrial fibrillation was documented in 107 patients. Compared with patients without atrial fibrillation, those with this arrhythmia were older, had clinically more severe infarction, and had a higher frequency of ventricular fibrillation or tachycardia, and right bundle-branch block. They had similar past histories of ischaemic heart disease and coronary risk factors. Patients with atrial fibrillation had a higher total mortality at 3 months and 12 months. The presence of atrial fibrillation was not associated with any significant increase in mortality within any decade of age or within any subgroup of clinical severity of infarction. The frequency of atrial fibrillation was similar in anterior and inferior infarction. Multiple episodes of atrial fibrillation occurred in 52 patients and episodes usually lasted for over 1 hour. In 50% of patients with single episode of atrial fibrillation the initial ventricular rate was greater than 120 beats per minute.

Acute Disease↗
PubMed1977

Changing patterns and mortality of acute myocardial infarction in a coronary care unit.

Three groups of patients who had been admitted to a coronary care unit with infarction at different periods since 1963 were reviewed to assess whether the outcome in such patients had improved over 12 years. There was a significant reduction in mortality among consecutive patients with mild or severe infarction between 1969-70 and 1974-5. Classifying the patients in all three groups according to their risk factors showed that for each risk factor mortality had decreased since 1963. The incidence of arrhythmias and conduction defects decreased between 1969-70 and 1974-5, and mortality among patients with each arrhythmia also fell. The reduction in mortality may reflect a changing pattern in the natural history of the disease as well as a benefit of improved treatment.

Adult↗
PubMed1977

Myocardial creatine kinase isoenzyme in serum after subarachnoid haemorrhage.

The myocardial isoenzyme of creatine kinase (MB CK) has been demonstrated in the serum of seven of 16 patients presenting with acute subarachnoid haemorrhage. All patients with elevated MB CK levels exhibited at some stage either intracranial arterial spasm as demonstrated by cerebral angiography, or a focal reversible neurological deficit not due to direct pressure by either intracranial haematoma or aneurysm. The presence of MB CK isoenzymes in sera of patients with subarachnoid haemorrhage may be an index of cerebral ischaemia, and may thus be of value in determining optimal timing of surgery or, ultimately, the long-term prognosis. Changes in the sympathetic nervous system may be a common factor producing both MB isoenzyme release from the myocardium and intracranial arterial spasm.

Brain↗
PubMed1977

Selective attention in fast and slow learners.

64 children aged 8 yr. were trained on a tactile simultaneous discrimination task. Selective attention was measured in terms of percentage contact time per trial to the relevant dimension. Inter- and intra-couplings per trial were also recorded. Multivariate analyses were carried out to examine the role of component factor scores, obtained from a component curve analysis of the percentage touching time per trial, and selected cognitive variables in differentiating between the fast and slow learner groups. Percentage touching time factor scores and a memory factor were significant, but there was no significant difference between the groups in the number of couplings made. As learning progressed the number of inter- and intra-couplings decreased.

Aptitude↗
PubMed1976

Autonomic and pharmacological control of oxygen autoregulation mechanisms in brain tissue.

The effect of several agents active on autonomic nervous system functions was tested on brain oxygen autoregulation parameters. It was found that atropine, propranolol and isproterenol had no influence on the measured parameters. Phenoxybenzamine, tolazoline and dibenamine all suppress autoregulation. In an additional experimental series, a phenoxybenzamine infusion was given during O2 breathing. The infusion induced a marked rise in TpO2. It is concluded that an alpha-adrenergic mechanism is part of the autoregulation process, and its pharmacological blockade could be used to raise TpO2 levels in brain with O2 breathing at normal atmospheric pressure. Also, the increase in brain TpO2 induced by 95% O2 - 5% CO2 breathing seems to be blocked by alpha-adrenolytic drugs.

Animals↗
PubMed1976

Changing results of treatment of infarction in a coronary case unit.

A comparison has been made between the first 300 patients admitted from 1963 to 1967 to the Coronary Care Unit (CCU) of The Royal Melbourne Hospital with transmural cardiac infarction, and two groups of similar numbers admitted in 1969 and 1974. While the age spectrum and duration of stay of survivors in the Unit has remained similar, there has been a reduction in mortality, most marked in the most recent group of patients. The improvement was seen in all age groups, but was statistically significant only in the patients under 50 years and over 70 years. The reduction occurred in both sexes and was most evident in the patients admitted with severe cardiac infarction. The improvement in results of treatment is due in part, at least, to improvements in management introduced since 1963.

Age Factors↗
PubMed1976

Wenckebach phenomenon in the exit area from a transvenous pacing electrode.

An unusual type of exist block from a transvenous pacing electrode was recorded in a 63-year-old man with an acute inferior infarct and cardiogenic shock. The pacemaker artefact to QRS interval increased gradually till there was loss of capture. A gradual change from I:I pacing rhythm to 4:3 and 3:2 Wenckebach cycles was recorded. This was followed by a fixed 2:I pacemaker artefact to QRS block.

Electrocardiography↗
PubMed1976

Cardiac effects of different tricyclic antidepressant drugs.

The effects of tricyclic antidepressants on the heart are reviewed. Statistically significant increases in heart rate and in atrioventricular conduction times were found following the administration of tricyclic drugs to 32 depressed patients. The method of His bundle electrocardiography was used to study atrioventricular conduction in ambulant patients and in patients admitted after an overdose of tricyclic antidepressant drugs. Distal conduction defects were frequently found in patients following tricyclic overdosage, but these were not seen with doxepin overdosage. Impaired distal conduction was also found in occasional patients on therapeutic doses of tricyclic drugs. Some animal experiments giving similar results to the above clinical findings are also described. The clinical implications of these findings are discussed.

Amitriptyline↗
PubMed1975

Learning by experience. A student residential workshop in hospital.

A four-day residential workshop was conducted for students beginning their clinical studies at the St George Hospital in 1974. The aim of the workshop was that the students should understand the functioning of the hospital and feel comfortable as students in the hospital, so that they would learn their clinical skills more effectively in their subsequent years at the hospital. Each student lived in a hospital bed with an "illness" for two days, and spent another two days helping care for these "student patients" and exploring the hospital. Evaluation at the end of the workshop suggested that the objectives had been achieved.

Attitude of Health Personnel↗
PubMed1975

Clinical experience with verapamil.

Verapamil administered by the intravenous route restored sinus rhythm in 33 out of 40 episodes of supraventricular tachycardia. The drug was also effective in reducing ventricular rate in patients with atrial fibrillation. Intracardiac conduction studies using His bundle electrograms showed prolongation of atrioventricular nodal conduction in eight out of nine cases after 5 mg of verapamil were given. The distal conduction was unaffected. Bradycardia and hypotension occurred in two cases and responded promptly to intravenous administration of atropine. Verapamil is an effective antiarrhythmic agent which is, in general, free from significant side effects.

Arrhythmias, Cardiac↗
PubMed1975

Establishment of the Melbourne mobile intensive care service.

As the majority of deaths after infarction occur in the first hour, a mobile intensive care ambulance service has been instituted in Melbourne to enable adequate care and early monitoring facilities. Initially the service was manned by doctors and ambulance officers, but currently each ambulance is manned by two specially trained officers. Over a 27-month period 52 patients have been resuscitated from ventricular fibrillation or ventricular standstill. Half of the patients had sustained a definite acute myocardial infarction and another 16 had probable but not proven myocardial infarction. Of the 52 patients, 31 survived to leave hospital and all patients known to be alive are leading active and useful lives. In spite of an initial fear that medical treatment might be overused or misused by the officers, this has not been the case, and only about 13% of patients have received drugs from the officers. This paper deals with the setting up, staffing and training of the ambulance service and reviews its results.

Adult↗