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Biomedical subjects

A Duffield

Publications and source records attributed to A Duffield.

6 recordsLinked to original sources

Predictors of reinfarction and sudden death in a high-risk group of acute myocardial infarction survivors.

75 patients aged under 70 years who had survived acute myocardial infarction complicated by both significant arrhythmias and cardiac failure were followed-up for 1 year in an attempt to identify features which suggest the likelihood of late death or reinfarction. Patients were carefully instructed in the identification and importance of possible prodromal symptoms and the availability of a mobile intensivecare ambulance service and a 24 h hospital control centre. Horizontal ST-segment depression or anginal pain on an exercise test done within 6 weeks of infarction was a useful predictor of late death. Routine twice weekly E.C.G. recordings taken by telephone transmitter at rest and after mild exertion resulted in the identification of significant arrhythmias in only 7 patients. 13 patients (17%) died, 5 of them instantaneously. 4 of the 13 patients and 22 of the 62 survivors reported "prodromal symptoms". Unreported prodromal symptoms were elicited retrospectively in 14 of the 62 survivors and from the relatives of 4 of the 13 patients who died. Thus, 35% of prodromal symptoms were not reported despite intensive patient education and counselling. The incidence of "prodromal symptoms" was no higher in patients who died than in those who did not die.

Acute Disease

Mitral valve prolapse.

Mitral valve prolapse is a relatively common condition in the general population. The syndrome appears more common in females, and is often associated with a family history. Patients may be asymptomatic or may present with a variety of symptoms ranging from mild chest aches and anxiety to severe angina-like chest pain, palpitations and dizziness. The common auscultatory features include mid-systolic clicks and a late systolic murmur, either alone or in combination. The wide spectrum of symptoms and signs may be explained by ventriculovalvular disproportion, where either the ventricle is too small for the valve, or the valve is too large for the ventricle. The long-term prognosis is very good; severe mitral regurgitation can occasionally develop, but both sudden death and bacterial endocarditis are rare. No treatment is required for asymptomatic patients, beyond antibiotic cover for dental procedures and surgery.

Adolescent

The use of balloon-tipped electrodes for permanent cardiac pacing.

A new balloon-tipped ventricular endocardial electrode for permanent artificial cardiac pacing is described. Following transvenous insertion of the electrode to the right ventricular apex, the distal balloon is inflated with contrast material in order to wedge the electrode tip between or beneath trabeculae and prevent displacement. fifty-nine electrodes were implanted, including a second generation type incorporating a wedge tip as well as the balloon. The incidence of displacement was 17% with 10% of cases being early, and 7% late. Early in the series, 50% Urografin was used to inflate the balloon and this resulted in premature deflation and early electrode displacement in two of the nine patients. When the concentration of Urografin was reduced, the balloon remained inflated for a longer period and the incidence of early displacement was reduced to 8%. However, there was still a late displacement of 8%. Only one wedge-tipped balloon electrode displaced. This electrode had a faulty sealing mechanism and the balloon could not be adequately inflated. There was a 3% incidence of early and a 3% incidence of late threshold problems with the electrode. However, name of the wedge-tipped balloon electrodes exhibited this problem. It was concluded that this new electrode did not fulfill its objectives. The total electrode failure rate, including displacements and episodes of high threshold was approximately 24%.

Aged

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

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