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Biomedical subjects

D S Reid

Publications and source records attributed to D S Reid.

At least 55 records · Page 3Linked to original sources
PubMed1984

Role of exercise testing early after myocardial infarction in identifying candidates for coronary surgery.

It has been suggested that ST depression in lead V5 or equivalent on early exercise testing after acute myocardial infarction predicts a high risk of death. To evaluate exercise testing and radionuclide ventriculography in this context 103 consecutive patients with myocardial infarction who were able to undertake a limited exercise test before discharge from hospital were exercised and underwent gated blood pool scanning. No serious complications resulted from exercise testing. Twenty nine patients developed ST depression in lead V5, 19 had exertional hypotension, 31 developed a heart rate of greater than or equal to 130 beats/min, and 15 had complex ventricular arrhythmias. Death during the first year after discharge from hospital was associated with exertional hypotension (p less than 0.001) and a heart rate on exercise testing of greater than or equal to 130 beats/min (p less than 0.05); these two variables identified all nine deaths. Inability to complete the exercise protocol for any reason was also predictive of death (p less than 0.01). Ventricular arrhythmias and ST depression in lead V5 induced by exercise were not significantly associated with an increased risk of death. The mean (SD) radionuclide ejection fraction in the patients who died was 29 (16%) compared with 43 (11)% in the patients who survived (p less than 0.001). ST changes on exercise testing after myocardial infarction appear to be less predictive of later complications than haemodynamic signs, which may indicate left ventricular damage rather than ischaemia.

Adult↗
PubMed1984

Aortic root abscess complicating bacterial endocarditis. Demonstration by computed tomography.

A 68 year old man with an aortic valve prosthesis was admitted to hospital with Staphylococcus aureus endocarditis. Despite antibiotic treatment he continued to be pyrexial. Computed tomography identified a probable abscess between the root of the aorta and the left atrium. The presence of an abscess in this location was subsequently confirmed at operation. Computed tomography is a useful additional diagnostic method for identifying this potentially lethal complication of bacterial endocarditis.

Abscess↗
PubMed1984

Sick sinus syndrome.

Explore the source record for details and available documents.

Anti-Arrhythmia Agents↗
PubMed1983

"Reciprocal" depression of the ST segment in acute myocardial infarction.

In acute myocardial infarction depression of the ST segment in leads distant from those showing ST elevation has been considered to be "reciprocal" but might reflect local ischaemia. To examine this possibility 103 consecutive patients who underwent exercise testing early after myocardial infarction were reviewed. Treadmill exercise testing was performed a mean of 12 (range 5-30) days after infarction using a limited Naughton protocol. Thirty five (34%) of the patients had had reciprocal change, defined as greater than or equal to 1 mm ST depression in leads remote from the site of the infarct, within 48 hours of infarction. Twenty two (63%) of the 35 patients developed exercise induced ST depression in the leads previously showing reciprocal change. Coronary artery disease was assessed in 10 of these patients by arteriography and in four at necropsy: all but one had stenosis of greater than or equal to 50% in a coronary artery supplying the reciprocal territory in addition to the disease in the vessel to the infarct site. Of patients with reciprocal ST depression, 23.5% experienced nonfatal reinfarction, pulmonary oedema after discharge, or death compared with only 9.5% of patients without reciprocal ST depression. Eight (23.5%) patients with reciprocal depression had ventricular fibrillation while in hospital compared with only two (3%) patients without. Reciprocal ST depression in acute myocardial infarction may reflect ischaemia in territory distant from the site of infarction and is associated with a high risk of fatal arrhythmias and late morbidity.

Adult↗
PubMed1983

Intravenous isosorbide dinitrate in acute left ventricular failure--a dose--response study.

The haemodynamic effects of intravenous isosorbide dinitrate (Cedocard) in patients with severe acute left ventricular failure have been assessed using incremental infusion rates from 50 to 800 micrograms min-1. For most patients most of the fall in pulmonary arterial diastolic pressure occurred by 200 micrograms min-1, with little further fall at higher doses. At 200 micrograms min-1 pulmonary arterial diastolic pressure fell from 29 to 23 mgHg (P less than 0.001), there was no significant change in cardiac index (1.9 to 2.0 L min-1 m-2) or heart rate (108 to 108 beats min-1). Despite high doses, no side effects were observed. Intravenous isosorbide dinitrate is effective and safe in the management of acute severe left ventricular failure. In most patients an infusion rate of about 200 micrograms min-1 produces optimal haemodynamic effects.

Adult↗
PubMed1983

Aorto-atrial fistula in rheumatoid arthritis.

A patient with severe deforming rheumatoid arthritis presented with a short history of chest pain. The clinical signs were of an unusual diastolic murmur and profound shock unresponsive to therapy. Post-mortem examination disclosed the unexpected finding of a large aorto-atrial fistula.

Aged↗
PubMed1982

Concentration dependence of the order-disorder transition of carrageenans. Further confirmatory evidence for the double helix in solution.

The temperature-induced changes in optical rotation which are associated with the order-disorder transition of carrageenans have been analysed to investigate the concentration dependence and hence to attempt to derive the number of polysaccharide chains involved in the ordered species at equilibrium. The consequences of the known polydispersity have been analysed by computer-modelling and it is shown that this need not cause misleading results. For iota-carrageenan segments of 0.1 M NaCl and 0.1 M KCl solution the results point to a two-chain state and therefore support the proposed double helix model. For chi-carrageenan segments the apparent average number of molecules involved in the ordered state at equilibrium is 3.7, suggesting that if double helices form here they aggregate further. The method of investigation may be generally applicable to measuring the number of chains which associate in ordered states in aqueous solutions of polysaccharides.

Carrageenan↗
PubMed1979

Labetalol infusion in acute myocardial infarction with systemic hypertension.

1 Fifteen patients with suspected acute myocardial infarction and systemic BP of greater than 160/110 mmHg were treated with an incremental infusion of labetalol. 2 Systemic BPs were safely and effectively lowered to less than 130 mm Hg systolic or 90 mmHg diastolic in all pateints. 3 Heart rate, mean pulmonary artery wedge pressure cardiac index and stroke work index were significantly reduced. 4 The dose of labetalol varied from 30 mg--440 mg and was significantly higher (mean 295 mg) in those patients with pre-existing systemic hypertension compared with others (mean 133 mg). 5 No side-effects occurred and all patients survived to leave hospital.

Adult↗
PubMed1978

The electrocardiogram in the assessment of the effect of drugs on cardiac arrhythmias.

The search for the ideal antiarrhythmic drug continues since none of the available agents offers optimum antiarrhythmic therapy. The continuing search coupled with the interest in the mechanisms of cardiac arrhythmias has led to the development of new techniques for the study of arrhythmias and antiarrhythmic drugs. In this article it is proposed to discuss the electrocardiographic methods used in the assessment of antiarrhythmic drugs. Firstly, to discuss the electrocardiogram in the assessment of the clinical electrophysiological properties of a drug and secondly, the electrocardiogram in the assessment of the value of the drug in the management of cardiac arrhythmias in man.

Arrhythmias, Cardiac↗
PubMed1978

Mechanical failure causing current leakage with unipolar pacemakers: significance and detection.

Pacemaker malfunction caused by mechanical failure at the site of electrode generator connection has been observed in 5 patients fitted with unipolar pacemakers. Intermittent failure to capture occurred in one patient. The fault was the same in each case and resulted from fracture of a plastic screw designed to hold an insulating cap in place over the electrode generator connection. Changes in impulse amplitude, relative pacing threshold, and distortion of the shape of the pacemaker impulse (overshoot of the leading and trailing limbs and prolongation of the plateau length) occurred in each case, and are helpful in making the diagnosis. In contrast no significant change occurred in the frontal plane axis of the pacemaker impulse. It is concluded that current leaks in unipolar pacemakers can be of sufficient magnitude to cause failure to capture. Early detection is important and is best achieved by examination of the pacemaker signal for amplitude and shape, and assessment of pacing threshold where possible.

Aged↗
PubMed1976

Electrocardiographic surface mapping of the heart following myocardial infarction and the influence of beta-blockade.

It is generally accepted that ST segment elevation is one of the characteristic electrocardiographic features of acute myocardial infarction. In experimental myocardial infarction the degree of ST segment elevation has been related to the degree of change in coronary flow. Surface mapping in patients of the electrocardiographic potentials gives an indirect representation of the epicardial ST segment change and in indication of the area of underlying myocardial damage. A number of patients who had sustained myocardial infar-tion within 72 hours were studied. All the patients had a history of prolonged ischaemic cardiac pain, electrocardiographic changes and a rise in serum enzymes. Electrocardiagrams were recorded from 72 points on the chest surface. Control maps were constructed from the ST segment changes measured at each of these points and plotted on a standard diagram. Electrocardiograms were recorded during a control period immediately before 20 mg of practolol was given intravenously over a period of five minutes. In all patients practolol produced a significant reduction in the area of ST segment elevation as represented by a reduction in the number of points with ST elevation of more than 2 mm. The significance of these findings is discussed.

Heart Rate↗