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Biomedical subjects

A D Timmis

Publications and source records attributed to A D Timmis.

156 records · Page 9Linked to original sources
PubMed1980

Haemodynamic effects of intravenous morphine in patients with acute myocardial infarction complicated by severe left ventricular failure.

The haemodynamic effects of intravenous morphine sulphate (0.2 mg/kg body weight) were measured in 10 patients with acute myocardial infarction complicated by severe left ventricular failure. Fifteen minutes after morphine injection there was a significant fall in mean heart rate (from 109 to 101 beats/min) and mean systemic arterial pressure (from 80 to 65 mm HG), and a small fall in mean cardiac index (from 2.4 to 2.21/min/m2). Haemodynamic changes at 45 minutes were similar. Neither stroke index nor indirect left ventricular filling pressure (measured as pulmonary artery end-diastolic pressure) were consistently improved 15 or 45 minutes after injection. The useful action of morphine in relieving distressing cardiac dyspnoea is not adequately explained by systemic venous blood pooling. These results suggest that the effects of morphine on the central nervous system are more important.

Aged↗
PubMed1980

Synergistic effects of a combined salbutamol-nitroprusside regimen in acute myocardial infarction and severe left ventricular failure.

The haemodynamic effects of a simultaneous infusion of salbutamol and nitroprusside were measured in 20 patients with acute myocardial infarction and severe left ventricular failure. Six patients also had clinical manifestations of cardiogenic shock. Ten patients received salbutamol first with the subsequent addition of nitroprusside; in the other 10 patients nitroprusside was infused first. Salbutamol was infused at a constant rate of 20 micrograms/min in all patients, while the dose of nitroprusside, which averaged 51.25 micrograms/min, was adjusted to reduce left ventricular filling pressure (measured as pulmonary artery end-diastolic pressure) to approximately 15 mm Hg with reference to sternal angle. Cardiac index increased in all patients from a mean of 1.8 to 2.6 l/min/m2 while pulmonary artery end-diastolic pressure fell significantly from 24 to 16 mm Hg. The adverse effects were small in most patients: heart rate did not increase significantly and systolic arterial pressure fell on average from 112 to 96 mm Hg. Ten of the 20 patients survived to leave hospital. Nitroprusside accounted for most of the fall in filling pressure irrespective of treatment sequence, whereas both drugs contributed to the augmented cardiac output. The haemodynamic benefits of this combined regimen were considerably greater than those achieved by either drug alone. Thus salbutamol and nitroprusside have synergistic effects which influence favourably the two principal manifestations of left ventricular dysfunction after extensive myocardial infarction.

Aged↗
PubMed1980

Salbutamol in treatment of heart failure.

The haemodynamic effects of oral and intravenous salbutamol were investigated in 22 patients with chronic heart failure. Intravenous salbutamol (13 micrograms/min) increased cardiac index by 53 per cent from 1.5 +/- 0.13 1/min per m2 to 2.3 +/- 0.23 1/min per m2 and decreased systemic vascular resistance by 28 per cent from 29.4 +/- 3.9 units to 21.2 +/- 2.5 units. Heart rate rose by 10 per cent from 101 +/- 3.5 beats per minute to 111 +/- 3.2 beats per minute and pulmonary artery end-diastolic pressure fell by 13 per cent from 26.3 +/- 1.8 mmHg to 22.8 +/- 2.1 mmHg. Similar results were obtained after oral salbutamol (8 mg). Cardiac index rose by 40 per cent and systemic vascular resistance fell by 30 per cent. There was a small rise in heart rate and a variable and not significant change in pulmonary artery end-diastolic pressure. Experiments on isolated rabbit papillary muscle showed that salbutamol, at the concentration which exists in patients, had no detectable positive inotropic effect. It is probable that the increase in cardiac output in patients is primarily the result of reduced afterload caused by vasodilatation. Salbutamol is a useful drug in the treatment of chronic heart failure.

Administration, Oral↗
PubMed1979

Haemodynamic effects of salbutamol in patients with acute myocardial infarction and severe left ventricular dysfunction.

The haemodynamic effects of salbutamol infusions at rates of 10,20, and 40 micrograms/min were measured in 11 patients with acute myocardial infarction complicated by left ventricular failure. Four patients also had cardiogenic shock. Consistent increases were observed in cardiac outputs at all doses (up to 56% at 40 micrograms/min), while the mean systemic arterial pressure fell slightly (average 5 mm Hg), implying a reduction in peripheral vascular resistance. Changes in right atrial pressure and indirect left atrial pressure (measured as pulmonary artery end-diastolic pressure) were small and not significant. Analysis of data from individual patients showed that the greatest increment in cardiac output was reached at 10 micrograms/min in two cases, 20 microgram/min in three, and 40 micrograms/min in the remaining six. Heart rate at these doses increased by an average of only 10 beats/min. Salbutamol failed to reduce left ventricular filling pressure and cannot be recommended for the treatment of pulmonary oedema in acute myocardial infarction. The increase in cardiac output, however, was considerable, so that the drug may be important in the management of low-output states. This action is probably a result of peripheral arteriolar dilatation (itself a result of beta 2-adrenoreceptor stimulation) and is achieved with little alteration in the principal determinants of myocardial oxygen requirement.

Adult↗
PubMedDate not supplied

Angiographic morphology of recurrent stenoses after percutaneous transluminal coronary angioplasty: are lesions longer at restenosis?

Angiographic morphology was analysed in 32 patients who developed restenosis after initially successful coronary angioplasty. The mean minimal luminal diameter of the dilated coronary segments increased from 0.9 mm to 2.3 mm after dilatation, but decreased to 0.9 mm at restenosis. The reference diameter was unchanged after dilatation and at restenosis. Mean stenosis length before the initial angioplasty was 7.0 mm but at the repeat procedure had increased to 8.7 mm (mean increase 1.7 mm, 95% confidence interval 0.6 to 2.8 mm, p less than 0.01). There were no significant differences in mean trans-stenotic pressure gradient and mean eccentricity ratio between the initial and repeat angioplasty procedures. In individual patients the changes in stenosis morphology were unpredictable, but overall stenoses tended to be longer at restenosis. In some patients stenosis length increased by several millimetres but the success rate of repeat angioplasty was high and the clinical importance of the changes in stenosis morphology are uncertain.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Selection bias in the management of unstable angina.

OBJECTIVES: To examine the criteria for selecting patients presenting with unstable angina for cardiac catheterisation and to assess the extent to which these criteria successfully incorporate high risk groups. METHODS AND RESULTS: This was a prospective cohort study of 517 patients admitted with unstable angina with 12 months follow-up; 139 patients (26.9%) had cardiac catheterisation 32 days or longer after presentation. The odds of early catheterisation were increased by regional ST segment depression on the presenting ECG (odds ratio (OR) 1.70, 95% confidence intervals (CI) 1.01-2.87) and ongoing ischaemic chest pain more than 12 hours after admission (OR 9.72, CI 6.10-15.49), and reduced by age over 65 years (OR 0.56, 95% CI 0.35-0.90) and heart failure (OR 0.26, CI 0.11-0.64). The 12-month rates of myocardial infarction (MI) or death were 8.6% and 17.7% (p = 0.01) in patients who were and were not referred for early cardiac catheterisation, respectively. Survival analysis showed that the odds of MI and death in the first 12 months were increased substantially by heart failure (OR 2.82, 95% CI 1.53-5.20) and age over 65 (OR 1.91, 95% CI 1.13-3.23). CONCLUSION: Selection for early cardiac catheterisation in this unstable angina population was largely ischaemia-driven, based on ongoing chest pain and ST segment depression. This policy was associated with a low event rate in the ischaemic group, but it failed to target elderly patients and those with heart failure who were at greatest risk of MI and death during the first year.

Aged↗
PubMedDate not supplied

One-stop chest pain clinic can identify high cardiac risk.

The aim of this study was to record prognosis for patients with stable chest pain referred for outpatient cardiac assessment. All 660 patients in the study had a normal resting ECG and no history of myocardial infarction, unstable angina or coronary revascularisation. Main outcome measures were all-cause mortality, non-fatal ischaemic events and coronary revascularisation. Cardiac chest pain was diagnosed in 182 patients (28%). It was more frequent in patients with recent onset of symptoms (< 6 months), patients over 50, white patients, and patients with hypertension or diabetes. The mean follow-up was 622 +/- 338 days. Among survivors, 37% continued to suffer from symptoms (cardiac group: 59 (35.1%); non-cardiac group: 177 (38.4%)). When all hard events were considered, event-free survival (95% confidence interval) for the cardiac group was 90.9% (86.7-95.2%) at six months, 88.9% (84.2-93.6%) at one year, and 83.6% (77.5-89.7%) at two years. Corresponding figures for the non-cardiac group at the same time points were better (p < 0.0001): 98.5% (97.4-99.6%), 97.5% (96.1-99.0%) and 96.6% (94.7-98.5%), respectively. In conclusion, the use of clinical criteria in a cardiac outpatient clinic, backed up by simple non-invasive investigations, can reliably identify a population at high risk of subsequent cardiac events.

Adult↗
PubMedDate not supplied

Computer-generated correspondence for patients attending an open-access chest pain clinic.

AIM: To determine whether general practitioners (GPs) prefer structured computer-generated or standard dictated outpatient clinic letters. DESIGN: Questionnaire survey of all GPs referring patients to an open-access chest pain clinic at a district general hospital in London. The GPs were asked to compare three twinned examples of structured computer-generated and unstructured dictated letters. RESULTS: Of 93 respondents (response rate 77.5%), 75 (80.6%) preferred the computer-generated letter and 16 (17.2%) preferred the dictated letter (p < 0.0005). The preferred features of the computer-generated letter were its clear presentation, subheadings, and concise information. The computer-generated letter scored significantly higher than the dictated letter: for clarity, mean 8.2 vs 6.5 (p < 0.0005); content, mean 8.5 vs 6.9 (p < 0.0005); and readability, mean 8.2 vs 6.8 (p < 0.0005). The GPs in the survey considered a mean delay of 3.4 days to be acceptable for receiving the letter from the chest pain clinic. CONCLUSION: GPs prefer structured computer-generated letters to unstructured dictated letters for patients referred to an open-access chest pain clinic. Computer-generated correspondence allows rapid feedback of information to the referring GP, one of the key requirements of open-access clinics.

Ambulatory Care Facilities↗