Biomedical subjects

D P Murray

Publications and source records attributed to D P Murray.

35 records · Page 2Linked to original sources

PubMed1988

A randomized trial of the efficacy and acceptability of a pen injector.

A controlled trial of pen injection of insulin was performed in 78 patients, with assessment of metabolic control and lifestyle. After a 6-week run-in period, during which control was optimized, the patients were randomized, either to stay on a twice daily insulin regimen (n = 37), or to change to a three times daily pen regimen with human ultralente at night (n = 41). Over the 20 weeks, there was no significant change in mean glycosylated haemoglobin (syringe, mean +/- SD, 11.1 +/- 2.5% to 10.9 +/- 2.0%; pen, 11.3 +/- 2.6% to 11.2 +/- 2.0%), in blood glucose profiles or in frequency of hypoglycaemic attacks in either group. A self-completed questionnaire demonstrated high patient satisfaction with the pen injector (NovoPen), 78% for effect on lifestyle and 81% for increased flexibility. Ninety-five percent preferred the pen injector regimen to conventional treatment and stayed on it.

Adult↗

PubMed1988

Does beta adrenergic blockade influence the prognostic implications of post-myocardial infarction exercise testing?

The influence of beta blockade on the ability of ST depression, during pre-discharge exercise testing, to predict coronary anatomy and subsequent complications was studied in 300 consecutive post-infarct patients, 125 of whom underwent cardiac catheterisation. At the time of exercise 62 patients were taking a beta blocker. The exercise test had a higher sensitivity in predicting multivessel disease in patients who were not taking beta blockers than in patients who were (95% v 76%). beta Blockade did not, however, influence the ability of the test to identify patients at risk of subsequent cardiac events (sensitivity 84% and 85% respectively). These results suggest that it is not necessary to stop treatment with beta blockers before predischarge exercise testing of patients who have had an acute myocardial infarction.

Adrenergic beta-Antagonists↗

PubMed1987

Routine exercise testing or thallium-201 scintigraphy for prediction of cardiac events post-myocardial infarction?

The efficacy of 12 lead exercise testing and rest/exercise 201Tl scintigraphy as indicators of coronary anatomy and prognosis was compared in 46 low risk survivors of acute myocardial infarction. The non invasive procedures were performed at discharge, and cardiac catheterization was performed six weeks post discharge. On exercise testing, ST depression in leads remote from the site of infarction was considered to indicate multivessel disease and reversible ischaemia. On 201Tl scintigraphy, a perfusion defect remote from the site of infarction indicated multivessel disease, while a defect which reperfused at rest indicated reversible ischaemia. During the mean follow-up of 13 +/- 3 months, 14(30%) patients experienced cardiac events. Thallium scintigraphy was a more sensitive, but less specific, indicator of multivessel disease than exercise testing. Both exercise testing and 201Tl scintigraphy had a similar sensitivity (79% vs 79%), specificity (78% vs 88%) and predictive accuracy (78% vs 85%) for predicting subsequent cardiac events. Thus, in our patient population, 201Tl scintigraphy could not be demonstrated to be superior to routine exercise testing in low risk patients post myocardial infarction.

Adult↗

PubMed1987

Beta-adrenergic blockade in acute myocardial infarction: a haemodynamic and radionuclide study.

While long term beta-adrenergic blockade, introduced in the convalescent stage of myocardial infarction, may reduce subsequent mortality, the value of early beta-blockade in the acute phase is less certain. Therefore, the influence of beta-blockade on left ventricular performance and eventual infarct size was assessed in 61 consecutive patients with acute myocardial infarction. Metoprolol (15 mg i.v. followed by 200 mg day-1 orally) or placebo was administered in a double-blind, randomised fashion with a median delay of 5.9 hours from onset of symptoms. After 15 days of double blind therapy all patients were started on open treatment with metoprolol. All patients underwent haemodynamic monitoring for 24 hours and serial radionuclide ventriculography and thallium 201 scintigraphy. In the first hour metoprolol produced a decrease in cardiac output (1.3 l min-1; P less than 0.001) due to a reduction in heart rate (15 min-1; P less than 0.001) and a decrease in left ventricular stroke work index (10.7 g m m-2; P less than 0.001) due to a reduction in mean arterial pressure (10 mmHg; P less than 0.001). There was then a gradual attenuation in these changes. While metoprolol produced an increase in pulmonary capillary wedge pressure and in both end-diastolic and end-systolic volumes (P less than 0.05), these changes were confined to patients with a baseline pulmonary capillary wedge pressure below the median of 13 mmHg mercury. There was no significant change in stroke volume or in ejection fraction in response to metoprolol. There was no significant difference between the groups in left ventricular performance, as assessed by radionuclide ventriculography, or in scintigraphic infarct size, either at the end of the 15 days double-blind treatment or after 3 months open treatment with metoprolol. Thus, early intervention with metoprolol in acute myocardial infarction appeared to reduce myocardial oxygen consumption with no adverse haemodynamic effect. However, metoprolol failed to preserve left ventricular function, or to reduce apparent infarct size. These data suggest that the modest reduction in mortality reported in the acute phase studies of beta-blockade in myocardial infarction, is unlikely to be due to infarct reduction. It is more likely to be due to a secondary prevention or to an antiarrhythmic effect.

Clinical Trials as Topic↗

PubMed1987

Prognostic stratification of patients after myocardial infarction.

An attempt was made to stratify risk of subsequent cardiac events in post-infarct patients according to a combination of the results of clinical assessment, routine diagnostic investigations, and pre-discharge exercise testing in 350 consecutive patients who were followed up for one year. Patients were classified prospectively on the basis of the extent of myocardial damage as assessed by peak enzyme release, reciprocal change on the electrocardiogram at the time of myocardial infarction, Norris prognostic index, ability to perform a pre-discharge exercise test (and test result), and ability to tolerate beta adrenergic blockade on discharge. Of the 50 patients with contraindications to pre-discharge exercise testing, 26% died or had reinfarctions compared with 9% of the 300 exercised patients; the 24 non-exercised patients with evidence of extensive myocardial damage or reciprocal changes on the electrocardiogram were particularly at risk. Similarly, among the 300 exercised patients, extensive myocardial damage, reciprocal change on the electrocardiogram, and ST depression on exercise testing were the major risk markers in that each identified at least 75% of the patients who had subsequent cardiac events. The 63 exercised patients who had all three of these major risk markers constituted a high risk group: 18 (29%) died or had reinfarction. Of the remaining 237 patients, only 9 (4%) had cardiac events. The 35 high risk patients with exercise induced angina pectoris or clinical contraindications to beta blockade were particularly at risk; 15 (43%) died or had reinfarction. This approach to risk stratification identified a small cohort of high risk patients in a large population of myocardial infarction survivors; it also identified a large group with a very low risk of subsequent cardiac events.

Electrocardiography↗

PubMed1986

Prognostic investigations after myocardial infarction: a comparison of radionuclide angiography and 201Tl scintigraphy.

The ability of pre-discharge thallium Tl201 scintigraphy and radionuclide angiography (RNA) to predict subsequent cardiac events was investigated in 46 apparently low-risk survivors of a first acute myocardial infarction. All patients underwent selective coronary arteriography at 3 months post-discharge. At the time of the initial investigation, half were beta-blocked, and thereafter, all patients were given prophylactic beta-blockade. During a mean follow-up period of 12 +/- 4 months, 14 patients (30%) experienced cardiac events, i.e. recurrent myocardial infarction (3 patients), angina pectoris (13 patients) and coronary surgery (8 patients). No patient died during the follow-up period. Of the 14 with subsequent cardiac events, 11 were identified by the presence of a reversible perfusion defect at 201Tl scintigraphy, while 7 exhibited abnormal left ventricular exercise reserve on RNA. The predictive accuracy of 201Tl (85%) for subsequent cardiac events exceeded that of RNA (56%; P less than 0.01) and of arteriographic multi-vessel disease (65%; P less than 0.05). The sensitivity of the non-invasive techniques was not influenced by beta-blockade at the time of investigation. Thus, 201Tl scintigraphy appears to be the more accurate technique for the assessment of the prognosis of apparently low-risk patients following myocardial infarction. The accuracy of the technique was not reduced by beta-adrenergic blockade.

Adult↗

PubMed1986

Natural evolution of left ventricular haemodynamics following uncomplicated acute myocardial infarction.

In an attempt to investigate the changes in left ventricular haemodynamics following uncomplicated myocardial infarction 95 patients with definite electrocardiographic signs of infarction, without clinical signs of cardiac failure, were monitored with a Swan Ganz catheter for the first 24 hours after admission to hospital. The median delay from onset of symptoms was 6.8 hours. Mean heart rate increased (83-86 beats/min; P less than 0.05) while stroke volume index fell (38.4-36.6 ml/m2; P less than 0.05); cardiac index therefore remained unchanged during the observation period. As a result of a fall in arterial pressure both systemic vascular resistance and left ventricular stroke work index fell significantly (P less than 0.01). Pulmonary wedge pressure also fell (13.6-10.5 mm Hg; P less than 0.001), but this fall was confined to patients whose initial reading was above the median of 13 mm Hg. Pulmonary wedge pressure fell both among the 41 patients who required some medical therapy (15.6-10.8 mm Hg; P less than 0.001) and the 54 who received no medication throughout the 24 hours (12.0-9.8 mm Hg; P less than 0.05). The 39 patients with anterior wall infarction had higher baseline pulmonary wedge pressure and systemic vascular resistance than the 42 with inferior wall infarction. Later the stroke volume and stroke work index were persistently lower reflecting the greater degree of impairment of left ventricular function in anterior wall infarction. In conclusion, following an uncomplicated myocardial infarction, cardiac index was maintained, despite a fall in stroke volume, by an increase in heart rate. Pulmonary wedge pressure showed both a spontaneous fall and a fall in those patients given additional medical therapy during the study period.

Aged↗

PubMed1986

The effects of metoprolol given early in acute myocardial infarction on ventricular arrhythmias.

The effects of metoprolol, administered in the early stages of acute myocardial infarction was studied in 126 patients. Patients were treated in a double-blind randomized fashion, with metoprolol -15 mg, intravenously followed by 100 mg twice daily for 15 days or placebo, with a mean delay of 8.1 hours from onset of symptoms. All patients underwent 24 hour Holter monitoring on days 1, 5 and 15 after randomization. Although there was no antiarrhythmic effect on day 1, metoprolol reduced the number of hours with warning arrhythmias (greater than 30 ventricular ectopics/hour, any R/T ectopics or ventricular tachycardia) on both days 5 (35 +/- 16% vs 8 +/- 11%; P less than 0.05) and day 15 (13 +/- 37% vs 4 +/- 13%; P less than 0.05). Metoprolol also reduced the incidence of ventricular fibrillation and ventricular tachycardia requiring cardioversion -6% vs 0%; P = 0.058. Metoprolol, administered in the early stages of acute myocardial infarction, had an antiarrhythmic effect which was evident only in the later phase of the study.

Administration, Oral↗

PubMed1986

The clinical role of thallium-201 scintigraphy in the management and prognosis of coronary artery disease.

The clinical impact of thallium-201 (Tl-201) scintigraphy in coronary artery disease was reviewed in 162 consecutive patients referred for routine investigation. Normal Tl-201 images were obtained in 86 of the 102 studies undertaken for diagnostic purposes. Eighty-one (94%) of the 86 were spared diagnostic coronary arteriography; 5 proceeded to coronary arteriography for persistent symptoms (1 had double vessel disease, 2 had single vessel disease only, 2 had normal arteriograms). Conversely, coronary arteriography was normal in 2 of 16 patients (12.5%) with unequivocal image defects. Tl-201 scintigraphy was performed as a functional complement to coronary arteriography in 60 patients, influencing the decision for surgery in 36 and determining the presence or absence of myocardial ischaemia in 24 patients with equivocal coronary arteriograms. Normal data were obtained in 9 patients. Of the 95 patients with normal Tl-201 scintigrams, only 5 (5.2%) required further investigations or intervention (4 arteriograms, 1 coronary angioplasty) over a follow-up period of 18 +/- 1 months, none suffered myocardial infarction and none died. There were no deaths in either the diagnostic or complementary group, irrespective of the result of the Tl-201 scintigram, during the mean follow-up period of 18 months. These data confirm both the valuable role of Tl-201 scintigraphy in the management of patients with suspected or proven coronary artery disease and the excellent prognostic value of a normal Tl-201 scintigram.

Adult↗

PubMed1984