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Biomedical subjects

J R Hampton

Publications and source records attributed to J R Hampton.

At least 91 records · Page 5Linked to original sources
PubMed1992

Predictors of risk in patients with unstable angina admitted to a district general hospital.

OBJECTIVE: To observe the long-term prognosis of patients with unstable angina and select simple criteria to identify high and low risk subgroups. DESIGN: A six month prospective survey with three year follow up. SETTING: One eleven bed coronary care unit. PATIENTS: All patients admitted with chest pain in whom no infarct was confirmed by subsequent electrocardiographic or enzyme changes and for whom no alternative cause of chest pain was found were studied. Unstable angina was also diagnosed if there was evidence of myocardial ischaemia in the form of previous effort angina, previous myocardial infarction, or if transient electrocardiographic changes accompanied the pain. When none of the above were present, chest pain without a known cause, was diagnosed. INTERVENTIONS: No routine intervention. Angiography and revascularisation for persistent symptoms despite medical treatment. OUTCOME MEASURES: Death or non-fatal infarction. RESULTS: In the 141 patients with unstable angina there were eight deaths and five non-fatal infarctions during the first eight weeks. Symptoms of increasing angina before admission were similar in all three groups and did not help predict early complications. Recurrence of pain in hospital, a rise in cardiac enzymes to less than twice the upper limit of normal, and transient electrocardiographic changes were all associated with an increased risk of early events. The presence of either abnormal enzyme activity or more than five episodes of pain in hospital identified a group of 49 in whom 11 of the 13 early events occurred. After three years, 29 of the 141 patients had died and eight had had infarctions (overall event rate 26%). Seventeen had undergone revascularisation (12%) and 51 (36%) were on antianginal treatment. Thirty six (26%) were still alive, without new myocardial infarction, and were free of angina. In the 29 patients with chest pain without a known cause there were no early events and only one non-fatal infarction during the three year follow up. CONCLUSION: When patients are admitted to the coronary care unit with chest pain not due to myocardial infarction, the history, electrocardiography and measurement of cardiac enzymes are sufficient to identify high and low risk subgroups.

Adult↗
PubMed1992

Myocardial infarction in patients over 75 1982-1990.

Admissions to hospital of patients aged 75 or over with symptoms suggestive of acute myocardial infarction have increased markedly since 1982. Patients over 75 present to hospital as soon after the onset of symptoms as do younger patients; they require more treatment with diuretics and digoxin than do younger patients and their fatality rate is higher. Despite this, the chance of patients over 75, especially women, being admitted to a Coronary Care Unit, and so being treated with a thrombolytic and being monitored closely for the complications of acute infarction are much less than those for patients under 75. If we are confident that we can influence the outcome of and reduce fatality from acute myocardial infarction, we should be prepared to offer elderly patients the same opportunities for treatment that we currently afford to younger patients.

Age Factors↗
PubMed1991

Assessing drugs for the treatment of heart failure.

The aims of treatment in patients with heart failure, as with any other condition, are to relieve symptoms and prolong life. A secondary objective is to do so at the lowest possible economic cost. When treatment of the cause of heart failure is possible--which usually means some form of surgery, but could include treatment of a primary disease, such as thyrotoxicosis--then this is obviously the treatment of choice. In patients for whom there is no such definitive treatment, a wide and increasing variety of drugs are available. When new antifailure drugs are to be developed there are therefore two problems: first, to ensure that they are more effective than placebo treatment, and second, to compare them with existing drugs. Both of these tests can present ethical difficulties, for it is unreasonable to withhold established effective treatment in order to conduct a placebo-controlled trial, and when drugs are being compared, it is unlikely that any new medication will be dramatically superior to an old one. The more effective the treatments already available, the harder it becomes to evaluate a new drug.

Drug Evaluation↗
PubMed1991

Exercise capability in heart failure: is cardiac output important after all?

The exercise capability of 39 patients with severe chronic heart failure was assessed in several ways and compared with measurements of cardiac output. The relation between cardiac index and exercise tolerance measured on a treadmill was poor (r = 0.191, p = 0.245). However, exercise tolerance measured with a series of self-paced corridor walk tests showed moderate correlations with cardiac index (r = -0.404, p = 0.015 to r = -0.516, p = 0.001) and customary activity assessed by step counting correlated better with cardiac index (r = 0.537, p less than 0.001). Cardiac output therefore seems to be a factor determining patients' exercise capability when they choose their own walking speed but not when they undergo formal treadmill tests in the laboratory.

Aged↗
PubMed1991

The treatment of hypertension: new lamps for old?

Meta-analysis of clinical trials does not help the clinician to treat individual patients. A general conclusion that the reduction of high blood pressure is beneficial has to be matched by specific information about the level of blood pressure that is acceptable and about the effect of particular doses of specific drugs. Results obtained from trials of "old-fashioned" antihypertensive drugs cannot confidently be extrapolated to "modern" agents. Sufficient data do not exist to encourage universal drug treatment for patients with "mild" hypertension.

Blood Pressure↗
PubMed1991

Perspectives of drug therapy in heart failure.

Despite an increasingly wide range of therapeutic options in heart failure management, fatality rates and morbidity remain high and new and better drugs are still needed. Assessing drug efficacy, and comparing two drugs, is difficult. Studies with mortality as an endpoint need to be large and long-term, and studies using exercise tolerance as an endpoint have inherent problems of design and execution. Although haemodynamic measurements are useful in assessing acute drug effects they are not helpful in the chronic state and a 'surrogate' endpoint for assessing heart failure is needed. Measurements of calf blood flow at rest and after exercise provide results that correlate with the patient's clinical state and response to therapy. Measurements of calf blood flow and treadmill exercise time were found to be useful in comparing the effects of ibopamine with captopril in patients with chronic heart failure.

Cardiotonic Agents↗
PubMed1991

Exercise tolerance in patients with heart failure--how should it be measured?

The exercise capability of 12 patients with heart failure was investigated by a variety of different methods before and after treatment with the vasodilator flosequinan. Two treadmill protocols were used, a modified Bruce with incremental workloads and a fixed workload protocol. On placebo, mean exercise time was greater with the Bruce protocol, 526 (64) s, than with the fixed protocol, 359 (59) s, P less than 0.005. Flosequinan increased exercise time more with the fixed protocol, so after 5 weeks' treatment exercise time was the same with both protocols; 680 (64) s with the Bruce and 673 (147) s with the fixed protocol. When the results are expressed as work, the patients achieved less with the Bruce protocol, 7.8 (1.9) kJ, than with the fixed protocol 12.5 (1.5) kJ on placebo, P less than 0.01. After flosequinan, the respective values were 14.5 (2.8) and 25.3 (5.1) kJ. Flosequinan improved corridor walk test times but there was no relationship between this and either treadmill test. Pedometer scores of customary activity were unchanged by flosequinan and were not correlated with any other exercise test. Different methods of assessing exercise capability provide different measures of patients' incapacity.

Clinical Protocols↗
PubMed1991

The need for standards for audit of coronary surgery and angioplasty.

The purpose of auditing is to improve clinical practice, but there is little point in auditing the management of a single patient or a series of patients unless the correct management has been established. Auditing should involve comparing case management with a standard and should not be based on individual opinion. This review considers how standards for auditing of coronary artery surgery and angiography can be defined, and it describes recent publications of different types that potential auditors should consider before beginning their task. These publications include series of patients, registers, committee statements, and ratings of "appropriateness."

Angioplasty, Balloon, Coronary↗
PubMed1991

Post-prandial worsening of angina: all due to changes in cardiac output?

BACKGROUND: The precise mechanism leading to the post-prandial worsening of angina has yet to be adequately defined. It has been attributed to an increase in double product but is perhaps more likely to be related to an increase in cardiac output after food. This study was designed to evaluate the effects of food on patients' exercise tolerance and compare these with changes in haemodynamic variables. METHODS: 23 patients with chronic stable angina who had post-prandial worsening of their angina were studied. The patients were evaluated on two occasions and at each visit they underwent two symptom limited treadmill exercise tests. They remained fasting on the first visit and were given a 1400 kcal meal 60 minutes before the second exercise test on the second visit. Time to onset of 1 mm ST segment depression, heart rate, systemic arterial blood pressure, and cardiac output were measured at rest and during exercise. RESULTS: There were no differences in any of the variables during the two exercise tests on the day the patients remained fasting. After the meal exercise tolerance fell significantly by 136 seconds and the stage at which 1 mm ST segment depression was first seen was also significantly reduced. Resting cardiac output increased significantly by 0.86 1/min with the patients sitting and by 0.89 1/min standing. The exercise times after food were significantly related to cardiac output even when fasting times were taken into account. Resting heart rate increased significantly by 8.3 beats per minute sitting and 10.4 beats per minute standing. There was little change in blood pressure and no evidence that the double product predicted the post-prandial exercise time. CONCLUSIONS: Worsening of angina was related to the increase in cardiac output after a meal and successful treatment will depend upon the prevention of this increase.

Aged↗
PubMed1990

Secondary prevention of acute myocardial infarction with beta-blocking agents and calcium antagonists.

The discovery that beta blockers possess clinically useful hypotensive, antianginal and antiarrhythmic properties has attracted the interest of clinicians, researchers and the pharmaceutical community alike. In addition, minor differences in a variety of ancillary properties have led to speculation that specific classes of drugs might have advantages over other classes. The enthusiasm that greeted reports from the first small trials, which showed that beta blockers reduced the postmyocardial infarction mortality rate, attracted the commercial support necessary to evaluate different beta blockers in this clinical setting. The plethora of beta blockers that subsequently became available for study led to considerable improvement in both the design and implementation of large clinical trials. Despite apparent discrepancies in the results of various trials, meta-analysis indicates that most, if not all, beta blockers reduce postinfarction mortality. However, because meta-analysis cannot recommend a particular drug or specific dose for use in an individual patient, clinical practice must be based on the results of individual trials, not on the conclusions of meta-analysis. The clinical utility of beta blockers in the secondary prevention of myocardial infarction, coupled with experimental evidence that calcium antagonists reduce infarct size, led to a series of large studies designed to establish whether calcium antagonists have any effect on reducing mortality in patients with myocardial infarction. Lessons learned from the beta-blocker trials permitted a more rapid evaluation of the efficacy of calcium antagonists in this setting. It is clear that, unlike beta blockers, calcium antagonists are not effective in the secondary prevention of myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1990

Audit of coronary angiography and bypass surgery.

The appropriateness of coronary angiography and coronary artery bypass surgery in the Trent regional health authority was assessed by comparison with predetermined consensus criteria. 49% of coronary angiographies were considered to be entirely appropriate in relation to the patient's clinical condition, but 21% were deemed inappropriate. Coronary artery bypass surgery was considered appropriate in 55% of patients, but inappropriate in 16%. Audit by "appropriateness" scores may help to determine which patients should first be investigated and treated when resources are limited and waiting lists are long.

Adult↗
PubMed1990

Effects of alteplase in acute myocardial infarction: 6-month results from the ASSET study. Anglo-Scandinavian Study of Early Thrombolysis.

In a randomised, controlled trial 2514 patients with suspected acute myocardial infarction received 100 mg intravenous alteplase (recombinant tissue plasminogen activator [rt-PA]) plus heparin within 5 h of onset of symptoms, and 2499 similar controls received placebo plus heparin. At 1 month the overall mortality rates were 7.2% and 9.8%, respectively, a relative reduction of 26% (95% confidence interval [CI] 11-39%). At 6 months the mortality rates were 10.4% (alteplase) and 13.1% (placebo), a relative reduction of 21% (95% Cl 8%-32%, p = 0.0026). 6-month mortality rates in patients with proven myocardial infarction were 12.6% and 17.1%, respectively (relative reduction 26%; 95% Cl 14-37%); this effect was similar for anterior (15.6% vs 21.2%) and inferior (7.7% vs 12.8%) myocardial infarction. 6-month mortality rates were lower in those treated with alteplase irrespective of other recognised cardiac risk factors. However, treatment with alteplase made no difference to subsequent cardiac events after one month (readmissions, reinfarctions, death) nor to treatment for angina or heart failure. Product limit estimates of one year mortality are 13.2% with alteplase and 15.1% with placebo. The corresponding figures for patients with an index diagnosis of myocardial infarction are 15.7% and 18.9%, a relative reduction of 16.9%.

Adolescent↗
PubMed1990

Effects of enoximone in patients with heart failure uncontrolled by captopril and diuretics.

Ten patients with severe heart failure, symptomatic despite treatment with diuretics and captopril, completed a study of the effect of adding enoximone to their normal treatment. Enoximone or matching placebo was given for 4 weeks in randomized double-blind order following a single-blind placebo run-in period. Exercise capability was measured with two different treadmill protocols, a corridor walk test and by step-counting with body-worn pedometers. Cardiac output and limb blood flow were assessed non-invasively by measuring respiratory gases and by venous occlusion plethysmography. Measurements were made at rest and in response to treadmill exercise. The mean exercise tolerance measured using the modified Bruce treadmill protocol was increased from the placebo value (498 +/- 91 seconds) after both 2 weeks (573 +/- 94 seconds, P = 0.051) and 4 weeks of enoximone (572 +/- 100 seconds, P = 0.057). Enoximone increased exercise duration in fixed workload tests from the placebo value (252 +/- 75 seconds) after 2 weeks' treatment (431 +/- 98 seconds, P = 0.011) and after 4 weeks (381 +/- 85 seconds, (P = 0.01). The percentage improvement with the fixed workload test was greater than with the modified Bruce protocol at week 2 (P = 0.03) and at week 4 (P = 0.051). Enoximone increased the speed of walking 100 m at self-selected slow, normal and fast paces. It had little effect on customary activity of the patients. Enoximone increased cardiac output measured at rest and during submaximal exercise (P = 0.001). It also improved blood flow to the calf muscle at rest and after exercise (P = 0.01). Enoximone has a beneficial effect in chronic heart failure symptomatic despite treatment with diuretics and captopril. The magnitude of its effect, however, depends upon the technique used to assess it.

Aged↗
PubMed1990

Effects of food on the central and peripheral haemodynamic response to upright exercise in normal volunteers.

The central and peripheral haemodynamic effects of a modest meal were investigated in healthy volunteers at rest and in response to submaximal exercise. The meal increased heart rate, cardiac output, oxygen consumption, carbon dioxide production, and minute ventilation at rest and during exercise. The effects of food were additive to those induced by the exercise. Food had no effect on limb blood flow and lowered total systemic vascular resistance suggesting that there were no compensatory changes in regional blood flow to help redirect blood to the gut. An increase in cardiac output, and therefore myocardial work, is the predominant cardiovascular response to eating and this may help explain the postprandial deterioration in symptoms of some patients with cardiovascular disorders.

Adult↗
PubMed1990

The limited potential of special ambulance services in the management of cardiac arrest.

For six months a survey was made of all the patients in the Nottingham District Health Authority who died or who were brought to hospital after a cardiac arrest outside hospital. During this period just under half of the emergency ambulance shifts were covered by specially trained crews with defibrillators. During the study period the ICD coding of death certificates indicated that 894 (25%) of the 3575 deaths were due to ischaemic heart disease. During this period the ambulance service received 17,749 emergency calls, which included 445 patients who had cardiac arrests outside hospital. One hundred and forty seven of these patients were carried by ambulances equipped with defibrillators and resuscitation was attempted in 83. Seven patients survived to leave hospital. The special ambulance service was cost effective--a simple calculation suggests that the cost per life saved was approximately 2600 pounds, but it seems unlikely that special ambulance services will materially affect community fatality rates from ischaemic heart disease.

Adult↗