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Biomedical subjects

A S Hall

Publications and source records attributed to A S Hall.

At least 19 recordsLinked to original sources
PubMed2003

Identifying acute myocardial infarction: effects on treatment and mortality, and implications for National Service Framework audit.

BACKGROUND: The National Service Framework (NSF) for Coronary Heart Disease requires annual clinical audit of the care of patients with myocardial infarction, with little guidance on how to achieve these standards and monitor practice. AIM: To assess which method of identification of acute myocardial infarction (AMI) cases is most suitable for NSF audit, and to determine the effect of the definition of AMI on the assessment of quality of care. DESIGN: Observational study. METHODS: Over a 3-month period, 2153 consecutive patients from 20 hospitals across the Yorkshire region, with confirmed AMI, were identified from coronary care registers, biochemistry records and hospital coding systems. The sensitivity and positive predictive value of AMI patient identification using clinical coding, biochemistry and coronary care registers were compared to a 'gold standard' (the combination of all three methods). RESULTS: Of 3685 possible cases of AMI singled out by one or more methods, 2153 patients were identified as having a final diagnosis of AMI. Hospital coding revealed 1668 (77.5%) cases, with a demographic profile similar to that of the total cohort. Secondary preventative measures required for inclusion in NSF were also of broadly similar distribution. The sensitivities and positive predictive values for patient identification were substantially less in the cohorts identified through biochemistry and coronary care unit register. Patients fulfilling WHO criteria (n=1391) had a 30-day mortality of 15.9%, vs. 24.2% for the total cohort. DISCUSSION: Hospital coding misses a substantial proportion (22.5%) of AMI cases, but without any apparent systematic bias, and thus provides a suitably representative and robust basis for NSF-related audit. Better still would be the routine use of multiple methods of case identification.

Aged↗
PubMed2002

An evaluation of the beta-1 adrenergic receptor Arg389Gly polymorphism in individuals at risk of coronary events. A WOSCOPS substudy.

AIMS: The Glycine389 variant of the beta-1 adrenergic receptor generates markedly less cAMP when stimulated in vitro than the more prevalent Arginine389 variant and may confer protection against coronary events similar to that observed with beta-blockers. The aim of this study was to ascertain whether this Glycine389 variant protects against coronary events. METHODS AND RESULTS: We identified the genotype at position 389 of the beta1AR in 1554 individuals taken from men enrolled in the West of Scotland Coronary Prevention Study. Men with a coronary event (event group) were each matched for age and smoking status with two control subjects from the same cohort who had not had a coronary event (control group). We compared the distribution of genotypes in the event and control groups. Conditional logistic regression was used to calculate odds ratios for each of the genotypes. The prevalence of the three genotypes in the entire cohort was ArgArg 53.5%, ArgGly 39.6%, GlyGly 6.9%. The Arg389Gly beta-1 adrenergic receptor polymorphism was not associated with coronary events. Using the ArgArg genotype as the reference, the odds ratio for the ArgGly genotype was 1.1 (95% CI, 0.88-1.38) and for the GlyGly genotype it was 1.05 (95% CI, 0.68-1.62). CONCLUSION: Our longitudinal case-control study demonstrates that the Glycine389 variant of the beta-1 adrenergic receptor does not protect against coronary events.

Adult↗
PubMed2001

Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study.

OBJECTIVES: Use of cumulative mortality adjusted for case mix in patients with acute myocardial infarction for early detection of variation in clinical practice. DESIGN: Observational study. SETTING: 20 hospitals across the former Yorkshire region. PARTICIPANTS: All 2153 consecutive patients with confirmed acute myocardial infarction identified during three months. MAIN OUTCOME MEASURES: Variable life-adjusted displays showing cumulative differences between observed and expected mortality of patients; expected mortality calculated from risk model based on admission characteristics of age, heart rate, and systolic blood pressure. RESULTS: The performance of two individual hospitals over three months was examined as an example. One, the smallest district hospital in the region, had a series of 30 consecutive patients but had five more deaths than predicted. The variable life-adjusted display showed minimal variation from that predicted for the first 15 patients followed by a run of unexpectedly high mortality. The second example was the main tertiary referral centre for the region, which admitted 188 consecutive patients. The display showed a period of apparently poor performance followed by substantial improvement, where the plot rose steadily from a cumulative net lives saved of -4 to 7. These variations in patient outcome are unlikely to have been revealed during conventional audit practice. CONCLUSIONS: Variable life-adjusted display has been integrated into surgical care as a graphical display of risk-adjusted survival for individual surgeons or centres. In combination with a simple risk model, it may have a role in monitoring performance and outcome in patients with acute myocardial infarction.

Age Factors↗
PubMed2001

Long-term effects of 60-Hz electric vs. magnetic fields on IL-1 and IL-2 activity in sheep.

This study was designed to assess the effect of exposure to long-term extremely low-frequency electric and magnetic fields (ELF-EMF) from a 500 kV transmission line on IL-1 and IL-2 activity in sheep. The primary hypothesis was that the reduction in IL-1 activity observed in our two previous short-term studies (10 months) was due to EMF exposure from this transmission line. To repeat and expand these studies and to characterize the components of EMF responsible for the previously observed reduction in IL-1 activity, the current experiment examined not only the effect of exposure to electric and magnetic fields, but also the magnetic field component alone. In the current study, IL-2 was examined to characterize the effects of EMF exposure on an indicator of T cell responses. 45 Suffolk ewe lambs were randomized into three groups of 15 animals each. One group of animals was placed in the EMF pen, located directly beneath the transmission line. A second group was placed in the shielded MF (magnetic field only) pen, also directly beneath the transmission line. The third group of animals was placed in the control pen located several hundred meters away from the transmission line. During the 27 month exposure period, blood samples were taken from all animals monthly. When the data were analyzed collectively over time, no significant differences between the groups were found for IL-1 or IL-2 activity. In previous studies ewe lambs of 8-10 weeks of age were used as the study animals and significant differences in IL-1 activity were observed after exposure of these animals to EMF at mean magnetic fields of 3.5-3.8 microT (35-38 mG) and mean electric fields of 5.2-5.8 kV/m. At the start of the current study EMF levels were reduced as compared to previous studies. One interpretation of the current data is that magnetic field strength and age of the animals may be important variables in determining whether EMF exposure will affect IL-1 activity.

Analysis of Variance↗
PubMed2001

Left ventricular volume reduction without ventriculectomy.

Partial left ventriculectomy (the Batista procedure) to achieve left ventricular volume reduction (LVVR) has been advocated as an alternative to cardiac transplantation in patients with end-stage dilated left ventricles. Here, we describe a new technique of LVVR that uses realignment of the papillary muscles, thus avoiding ventriculectomy, and report preliminary results. Eight patients (all male, mean age 49.3 [range 38 to 70] years) underwent LVVR between October 1998 and March 2000 as an adjunct to surgical coronary revascularization. Five were assessed with echocardiography and cardiopulmonary exercise testing before and after (mean follow-up time 267 [range 94 to 416] days) the operation. LVVR significantly improved left ventricular end-diastolic volume (254 +/- 32 to 218 +/- 36 mL, p = 0.03), left ventricular ejection fraction (20.14% +/- 1.36% to 31.28% +/- 2.32%, p = 0.007), and exercise duration (from 394 +/- 88 to 611 +/- 79 seconds, p = 0.03). A nonsignificant improvement in maximal oxygen consumption was also observed. This technique of LVVR is relatively simple to perform and is accomplished through a small apical cardiotomy. Preliminary results show an encouraging functional improvement following surgery. Future controlled studies are required to assess this novel technique further.

Adult↗
PubMed2001

A simple benchmark for evaluating quality of care of patients following acute myocardial infarction.

OBJECTIVE: To develop a simple risk model as a basis for evaluating care of patients admitted with acute myocardial infarction. METHODS: From coronary care registers, biochemistry records and hospital management systems, 2153 consecutive patients with confirmed acute myocardial infarction were identified. With 30 day all cause mortality as the end point, a multivariable logistic regression model of risk was constructed and validated in independent patient cohorts. The areas under receiver operating characteristic curves were calculated as an assessment of sensitivity and specificity. The model was reapplied to a number of commonly studied subgroups for further assessment of robustness. RESULTS: A three variable model was developed based on age, heart rate, and systolic blood pressure on admission. This produced an individual probability of death by 30 days (P(30)) where P(30) = 1/(1 + exp(-L(30))) and L(30) = -5.624 + (0.085 x age) + (0.014 x heart rate) - (0.022 x systolic blood pressure). The areas under the receiver operating characteristic curves for the reference and test cohorts were 0.79 (95% CI 0.76 to 0.82) and 0.76 (95% CI 0.72 to 0.79), respectively. To aid application of the model to routine clinical audit, a normogram relating observed mortality and sample size to the likelihood of a significant deviation from the expected 30 day mortality rate was constructed. CONCLUSIONS: This risk model is simple, reproducible, and permits quality of care of acute myocardial infarction patients to be reliably evaluated both within and between centres.

Adult↗
PubMed2001

Poor prognosis of patients presenting with symptomatic myocardial infarction but without chest pain.

OBJECTIVE: To describe the clinical features, prognosis, and treatment of patients presenting with atypical forms of acute myocardial infarction. DESIGN: Consecutive cases of possible acute myocardial infarction were sought from coronary care registers, biochemistry records, and hospital management systems. Case notes were reviewed and predefined epidemiological and clinical variables were abstracted. SETTING: 20 adjacent hospitals in the former Yorkshire region. PATIENTS: 3684 consecutive cases of possible acute myocardial infarction admitted in a three month period were identified, of whom 2096 had a first episode of confirmed acute myocardial infarction. RESULTS: 20.2% of all patients admitted with an eventual diagnosis of acute myocardial infarction presented with symptoms other than chest pain. Compared with the group presenting with chest pain, these patients were older (76.6 v 69.1 years, p < 0.001), were more often women (54.6% v 35.3%, p < 0.001), and were more likely to have a history of heart failure (18.6% v 6.9%, p < 0.001). They had a higher 30 and 365 day mortality (49.2% and 61.0%, respectively) compared with patients presenting with chest pain (17.9% and 26.2%). In a Cox regression analysis the hazard ratio for presentation without chest pain was 1.60 (95% confidence interval 1.30 to 1.97) (p < 0.001) adjusted for age, heart rate, blood pressure, left ventricular impairment, and infarction with ST segment elevation as covariates. Importantly, they were also less likely to receive treatments with a proven ability to improve prognosis. CONCLUSIONS: Atypical presentation of myocardial infarction without chest pain is common and associated with increased mortality. This may result in part from a failure to use beneficial treatment strategies.

Age Distribution↗
PubMed1999

Ramipril reduces QT dispersion in patients with acute myocardial infarction and heart failure.

In a cohort of 67 patients from the Acute Infarction Ramipril Efficacy study, we showed that ramipril therapy was associated with a significant reduction in QT dispersion over a 2-month period after acute myocardial infarction. This reduction of ventricular repolarization inhomogeneity indicates an antiarrhythmic effect and may be an important additional mechanism for the reduced all-cause mortality and sudden death incidence achieved with angiotensin-converting enzyme inhibition after acute myocardial infarction.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Pre-polarized saline: an in vivo feasibility study of a potential contrast agent.

The potential for using pre-polarized liquids as contrast agents in vivo is investigated and the feasibility of the method demonstrated. In this study we show the enhancement obtained following intravenous delivery of pre-polarized saline into the antecubital vein of a volunteer. This form of contrast agent provides signal gain on time scales commensurate with its T(1) and allows repeated doses to be administered, thus making alternate acquisitions of data with and without enhancement practicable.

Adult↗
PubMed1999

QT dispersion as a predictor of long-term mortality in patients with acute myocardial infarction and clinical evidence of heart failure.

BACKGROUND: QT interval dispersion is a marker of inhomogeneous ventricular repolarization, and therefore has the potential to predict re-entry arrhythmias. Following acute myocardial infarction, increased QT dispersion has been associated with a higher risk of ventricular arrhythmias. However, whether or not QT dispersion predicts prognosis post-acute myocardial infarction is not clear. We addressed this issue by analysing the AIREX study registry. METHODS: AIREX was a follow-up study of 603 post-acute myocardial infarction patients who exhibited clinical signs of heart failure and were randomly allocated to ramipril or placebo. An interpretable 12-lead ECG obtained between day 0 and day 9 after the index infarction (median time 2 days) was available in 501 patients. We examined whether QT dispersion was a predictor of all-cause mortality in the AIREX study registry (mean follow-up 6 years). RESULTS: QT dispersion measurements were significantly increased in patients who subsequently died (QT dispersion: 92.0 +/- 38.5 ms vs 82.7 +/- 34.3 ins. P=0.005; rate corrected QT dispersion: 105.7 +/- 42.7 ms vs 93.1 +/- 35.9 ms, P<0.001). Univariate analysis showed that QT dispersion as a predictor of all-cause mortality risk (QT dispersion: hazard ratio per l0 ms 1.05, [95% CI 1.02 to 1.09]. P= 0.004; rate corrected QT dispersion: 1-07 [1.03 to 1.10], P<0.001): an increase of 10 ms added a 5-7%, relative risk of death. QT dispersion remained an independent predictor of all-cause mortality risk on multivariate analysis (QT dispersion: 1.05 [1.01 to 1.09], P=0.027; rate corrected QT dispersion: 1.05 [1.01 to 1.09]. P=0.022). CONCLUSION: QT dispersion. measured from Li routine 12-lead ECG following acute myocardial infarction complicated by heart failure provides independent information regarding the probability of long-term survival. However. the low sensitivity of this electrocardiographic marker limits its usefulness for risk stratification if used in isolation.

Aged↗
PubMed1999

beta blocker treatment and other prognostic variables in patients with clinical evidence of heart failure after acute myocardial infarction: evidence from the AIRE study.

OBJECTIVES: To examine clinical outcomes associated with optional beta blockade in a population of patients with evidence of heart failure after myocardial infarction. DESIGN AND PATIENTS: Data from the acute infarction ramipril efficacy (AIRE) study were analysed retrospectively. At baseline 22.3% of the patients were receiving a beta blocker. To minimise confounding, beta blocker and diuretic treatments, presence of clinical signs of heart failure, left ventricular ejection fraction, and 16 other baseline clinical variables were simultaneously entered in a multivariate Cox regression model. In addition, the same analysis was repeated separately within a high and a low risk group of patients, as defined according to the need for diuretic treatment. RESULTS: beta Blocker treatment was an independent predictor of reduced risk of total mortality (hazard ratio 0.66, 95% confidence interval (CI) 0. 48 to 0.90) and progression to severe heart failure (0.58, 95% CI 0.40 to 0.83) for the entire study population. There were similar findings in high risk patients requiring diuretics (0.59, 95% CI 0.40 to 0.86; and 0.58, 95% CI 0.38 to 0.89). CONCLUSIONS: beta Blocker treatment is associated with improved outcomes in patients with clinical evidence of mild to moderate heart failure after myocardial infarction. Most importantly, high risk patients with persistent heart failure appear to benefit at least as much as lower risk patients with transient heart failure.

Adrenergic beta-Antagonists↗
PubMed1998

Family therapy with intellectually and creatively gifted children.

Few family therapists have expertise in the psychology of giftedness, and little research has been conducted to determine the effectiveness of family therapy with talented children and their families. The purposes of this paper are: (1) to provide family therapists with information on the unique psychosocial stressors associated with giftedness and (2) to stimulate further research and development on the efficacy of family therapy in alleviating distress and actualizing potential in gifted and talented children and their families. The paper provides a critical overview of the existing research literature on gifted children and their families. First, current conceptualizations of giftedness are described. Then the research literature on the characteristics of intellectually and creatively gifted children and their families is reviewed with an emphasis on the endogenous (individual) and exogenous (systemic) factors that can create or exacerbate psychosocial problems. Finally, we suggest an eclectic, eco-systemic approach to three common concerns that bring gifted children and their families to therapy.

Affect↗
PubMed1998

Structure and in vitro function of human subcutaneous small arteries in mild heart failure.

The structure and function of subcutaneous small arteries from patients with mild heart failure (n = 27) 6-43 mo after myocardial infarction were compared with vessels from healthy control subjects (n = 10). Patients were randomized to treatment with placebo or the angiotensin-converting enzyme inhibitor ramipril starting 3-10 days after myocardial infarction. Dissected arterial vessels were mounted on a wire myograph for measurement of morphology and isometric tension. Morphology was not different in arteries from the three groups. Responses to norepinephrine, angiotensin II, and electrical field stimulation were similar in arteries from placebo-treated patients with mild heart failure and control subjects. Similarly, endothelium-dependent and -independent relaxation was normal in arteries from patients with mild heart failure. Ramipril therapy was associated with functional alterations: vasoconstrictor responses to norepinephrine and angiotensin II were significantly enhanced compared with placebo (P < 0.001). These data suggest that vascular structure and function are not different in vitro in subcutaneous arteries from placebo-treated patients with mild heart failure. Angiotensin-converting enzyme inhibitor therapy is associated with enhanced vasoconstriction to norepinephrine and angiotensin II, which may reflect upregulation of receptor-mediated events.

Aged↗