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Biomedical subjects

G C Sutton

Publications and source records attributed to G C Sutton.

At least 19 recordsLinked to original sources
PubMed2002

Measurement of left ventricular volume after anterior myocardial infarction: comparison of magnetic resonance imaging, echocardiography, and radionuclide ventriculography.

We have compared echocardiography (echo) and radionuclide ventriculography (RNV) with magnetic resonance imaging (MRI) for the measurement of left ventricular (LV) volume and ejection fraction. Seventy asymptomatic patients were studied up to 12 days after first Q wave anterior myocardial infarction and again after 6 months. Each patient had LV volume measured by all three techniques within 24 hours of each other on each occasion. LV end-systolic and end-diastolic volume index (LVESVI and LVEDVI) and LV ejection fraction (LVEF) were measured using the modified Simpson formula (echo), a counts-based method (RNV), and a multislice area summation method (MRI). Radionuclide volumes were measured both with and without correction for attenuation of isotope. Echocardiography overestimated LV volume compared with MRI. Mean (SD) differences (echo-MRI) were: LVEDVI + 10.6 ml/m2 (16.8), LVESVI + 13.7 ml/m2 (12.9), LVEF -8.5% (11.2). RNV underestimated both volume and ejection fraction compared with MRI. Mean differences (RNV-MRI) were: LVEDVI -25.4 ml/m2 (23.8), LVESVI -5.0 ml/m2 (18.6), LVEF -13.8% (10.4). Variability in the difference between echo and MRI and between RNV and MRI was very similar for LVEF (coefficient of variation 23.9% echo, 22.2% RNV) but there was greater variability in the radionuclide than the echo measurements of absolute volume. Variability of the radionuclide measurements was reduced by not correcting for attenuation, and this finding may improve the radionuclide technique for serial measurements of percentage change in volume. Long-term inter-study reproducibility of MRI for LVEF (coefficient of reproducibility) was 10.9%, for echo it was 10.6%, and for RNV it was 14.6%. We conclude that measurements of LV volume depend on the method used and are not interchangeable. Echocardiography agrees more closely with MRI than RNV for the measurement of absolute volume, but the two techniques are similar for the measurement of LVEF.

Echocardiography↗
PubMed2002

Hospitalization of patients with heart failure: a population-based study.

AIMS: To describe the clinical course of heart failure in a population-based sample of incident cases, and to identify factors predicting hospitalization and mortality. METHODS AND RESULTS: Three hundred and thirty-two incident cases were identified over 15 months; 208 inpatients and 124 outpatients. Thirty-eight inpatients died during the first hospital admission (case fatality 18%) leaving 294 at risk of subsequent hospitalization. Over an average follow-up of 19 months, 173 cases were hospitalized on 311 occasions. Two hundred and twenty-four (72%) of these admissions were unplanned, with 51% due to worsening heart failure. One hundred and ten cases died over the same period. Cases diagnosed as an inpatient had 26 more admissions for worsening heart failure per 100 cases during follow-up (95% CI 9 to 44) compared to cases diagnosed as an outpatient, and also a higher mortality (hazard ratio 3.1 (95% CI 1.9 to 5.1)). Age was the only factor associated with an increased risk of hospitalization for worsening heart failure, but age, functional class and serum creatinine were predictive of mortality. CONCLUSIONS: New cases of heart failure are at high risk of subsequent hospitalization, especially during the first months after diagnosis. Whilst predicting which patients will be hospitalized is difficult, interventions designed to reduce hospitalizations for worsening heart failure should be targeted at elderly inpatients with a new diagnosis.

Age Factors↗
PubMed2002

The core of bluetongue virus binds double-stranded RNA.

Double-stranded RNA (dsRNA) viruses conceal their genome from the host to avoid triggering unfavorable cellular responses. The crystal structure of the core of one such virus, bluetongue virus, reveals an outer surface festooned with dsRNA. This may represent a deliberate strategy to sequester dsRNA released from damaged particles to prevent host cell shutoff.

Binding Sites↗
PubMed2001

Translocation portals for the substrates and products of a viral transcription complex: the bluetongue virus core.

The bluetongue virus core is a molecular machine that simultaneously and repeatedly transcribes mRNA from 10 segments of viral double-stranded RNA, packaged in a liquid crystalline array. To determine how the logistical problems of transcription within a sealed shell are solved, core crystals were soaked with various ligands and analysed by X-ray crystallography. Mg(2+) ions produce a slight expansion of the capsid around the 5-fold axes. Oligonucleotide soaks demonstrate that the 5-fold pore, opened up by this expansion, is the exit site for mRNA, whilst nucleotide soaks pinpoint a separate binding site that appears to be a selective channel for the entry and exit of substrates and by-products. Finally, nucleotides also bind to the outer core layer, providing a substrate sink.

Base Sequence↗
PubMed2001

Coronary artery disease as the cause of incident heart failure in the population.

AIMS: New approaches in the treatment of ischaemic left ventricular dysfunction, including revascularization, make it increasingly important to identify heart failure cases resulting from coronary artery disease. Without angiography these cases may be missed. We investigated the frequency of coronary artery disease in incident cases of heart failure in the population. METHODS AND RESULTS: We identified all incident cases of heart failure in a population of 292 000 in South London, U.K. by monitoring patients admitted to hospital and through a rapid access heart failure clinic. The presence and severity of coronary artery disease was identified by coronary angiography in patients under 75 years. Myocardial perfusion scanning was used to elucidate the aetiological significance of the coronary artery disease and identify hibernating myocardium. Three hundred and thirty-two cases of new heart failure were identified over 15 months. One hundred and thirty-six cases were under 75 years and angiography was undertaken in 99/136 (73%). Coronary artery disease was the aetiology in 71/136 (52%). In 18 of these 71 cases (25%), the aetiology was not recognised to be due to coronary artery disease prior to angiography, including eight cases with hibernating myocardium. CONCLUSION: Coronary artery disease is the cause of 52% (95% CI 43-61%) of incident heart failure in the general population under 75 years. Clinical assessment without angiography under-estimates the proportion of patients with coronary artery disease, and fails to identify those patients who may benefit from revascularization.

Adult↗
PubMed2001

Cancer screening coverage of south Asian women in Wakefield.

OBJECTIVE: To measure the cervical and breast screening coverage of south Asian women in Wakefield, compared with other city residents. DESIGN: Pairwise measurement of screening histories of women whose names appeared to be south Asian, and of non-Asian women matched by date of birth and general practice. DATA SOURCE: Computerised records of screening histories held by West Yorkshire Central Services Agency, for the eight general practices in central Wakefield. RESULTS: 67% of south Asians and 75% of non-Asians had acceptable (not overdue) cervical screening histories (chi(2)=13.75, p<0.001). 53% of south Asians and 78% of non-Asians had acceptable breast screening histories (chi(2)=8.5, p<0.01) CONCLUSION: Interventions should be designed to improve coverage for breast screening among south Asian women. The need for such interventions for cervical screening is equivocal.

Adult↗
PubMed2000

A Rapid Access Heart Failure Clinic provides a prompt diagnosis and appropriate management of new heart failure presenting in the community.

BACKGROUND AND AIMS: The diagnosis of heart failure is an important clinical problem and yet reported diagnostic accuracy in primary care is less than 50%. We established a Rapid Access Heart Failure Clinic (RAHFC) in a district general hospital serving a population of 292,000 in SE London, UK, to diagnose and manage new cases of heart failure presenting for the first time in the community. METHODS: Patients with suspected new onset heart failure were referred by their Primary Care Physician without appointment for clinical assessment on the same or next working day. Assessment by a specialist registrar in cardiology included history, examination, chest X-ray, electrocardiogram (ECG) and echocardiogram. When a diagnosis of heart failure was made appropriate treatment, including angiotensin converting enzyme inhibitors (ACEI), was started. RESULTS: Over 15 months 383 patients were seen (0.4 cases/100,000 population/weekday) 178/383 (46%) were considered to have definite or possible heart failure at the initial assessment in the RAHFC. A normal ECG (negative predictive value 94%) and chest X-ray virtually excluded the diagnosis of heart failure. After subsequent specialist investigations and follow-up, including a trial of therapy where appropriate, 101/383 (26%) were finally diagnosed as clinical heart failure. ACEI therapy was commenced in 56/57 (98%) of patients in whom it was considered appropriate. CONCLUSION: The RAHFC provided rapid assessment, prompt diagnosis and early introduction of life prolonging therapy for patients presenting with suspected heart failure in the community.

Aged↗
PubMed2000

Survival of patients with a new diagnosis of heart failure: a population based study.

OBJECTIVE: To describe the survival of a population based cohort of patients with incident (new) heart failure and the clinical features associated with mortality. DESIGN: A population based observational study. SETTING: Population of 151 000 served by 82 general practitioners in west London. PATIENTS: New cases of heart failure were identified by daily surveillance of acute hospital admissions to the local district general hospital, and by general practitioner referral of all suspected new cases of heart failure to a rapid access clinic. INTERVENTIONS: All patients with suspected heart failure underwent clinical assessment, and chest radiography, ECG, and echocardiogram were performed. A panel of three cardiologists reviewed all the data and determined whether the definition of heart failure had been met. Patients were subsequently managed by the general practitioner in consultation with the local cardiologist or admitting physician. MAIN OUTCOME MEASURES: Death, overall and from cardiovascular causes. RESULTS: There were 90 deaths (83 cardiovascular deaths) in the cohort of 220 patients with incident heart failure over a median follow up of 16 months. Survival was 81% at one month, 75% at three months, 70% at six months, 62% at 12 months, and 57% at 18 months. Lower systolic blood pressure, higher serum creatinine concentration, and greater extent of crackles on auscultation of the lungs were independently predictive of cardiovascular mortality (all p < 0.001). CONCLUSIONS: In patients with new heart failure, mortality is high in the first few weeks after diagnosis. Simple clinical features can identify a group of patients at especially high risk of death.

Adult↗
PubMed1999

The structure of a cypovirus and the functional organization of dsRNA viruses.

Cytoplasmic polyhedrosis virus (CPV) is unique among the double-stranded RNA viruses of the family Reoviridae in having a single capsid layer. Analysis by cryo-electron microscopy allows comparison of the single shelled CPV and orthoreovirus with the high resolution crystal structure of the inner shell of the bluetongue virus (BTV) core. This suggests that the novel arrangement identified in BTV, of 120 protein subunits in a so-called 'T=2' organization, is a characteristic of the Reoviridae and allows us to delineate structural similarities and differences between two subgroups of the family--the turreted and the smooth-core viruses. This in turn suggests a coherent picture of the structural organization of many dsRNA viruses.

Bluetongue virus↗
PubMed1999

Incidence and aetiology of heart failure; a population-based study.

AIMS: To determine the incidence and aetiology of heart failure in the general population. METHODS AND RESULTS: New cases of heart failure were identified from a population of 151 000 served by 82 general practitioners in Hillingdon, West London through surveillance of acute hospital admissions and through a rapid access clinic to which general practitioners referred all new cases of suspected heart failure. On the basis of clinical assessment, electrocardiography, chest radiography and transthoracic echocardiography, a panel of three cardiologists decided that 220 patients met the case definition of new heart failure over a 20 month period (crude incidence rate of 1.3 cases per 1000 population per year for those aged 25 years or over). The incidence rate increased from 0.02 cases per 1000 population per year in those aged 25-34 years to 11.6 in those aged 85 years and over. The incidence was higher in males than females (age-adjusted incidence ratio 1.75 [95% confidence interval 1.34-2.29, P<0.0001]). The median age at presentation was 76 years. The primary aetiologies were coronary heart disease (36%), unknown (34%), hypertension (14%), valve disease (7%), atrial fibrillation alone (5%), and other (5%). CONCLUSIONS: Within the general population, new cases of heart failure largely occur in the elderly, and the incidence is higher in men than women. The single most common aetiology is coronary heart disease, but in a third of cases the aetiology cannot be determined on the basis of non-invasive investigation alone. To be relevant to clinical practice, future clinical trials in heart failure should not exclude the elderly.

Adult↗
PubMed1998

Anticoagulation for cardioversion of atrial arrhythmias.

We would advocate 3 weeks of anticoagulation prior to, and 4 weeks post-cardioversion (either electrical or chemical) for patients in chronic atrial fibrillation or flutter. In selected cases it seems reasonable to use transoesophageal echocardiography to exclude preformed thrombus and negate the need for 3 weeks of prior anticoagulation. For patients presenting acutely with atrial fibrillation or flutter we suggest anticoagulating with heparin immediately on presentation and for those who do not spontaneously revert to sinus rhythm, using transoesophageal echocardiography to exclude atrial thrombi prior to cardioversion. Oral anticoagulation should be continued for 4 weeks post-procedure. If transoesophageal echocardiography is not readily available an alternative strategy would be to anticoagulate the patient for 3 weeks and thereafter readmit them for elective cardioversion, continuing the anticoagulation for a further 4 weeks after the procedure.

Acute Disease↗
PubMed1998

Abnormal ventricular activation and repolarisation during dobutamine stress echocardiography in coronary artery disease.

OBJECTIVE: To assess possible ECG changes caused by dobutamine stress and their relation to wall motion disturbances in patients with coronary artery disease. DESIGN: Prospective recording and analysis of 12 lead ECG at rest and during each stage of dobutamine stress echocardiography, and correlation with wall motion changes. SETTING: A tertiary referral centre for cardiac disease equipped with non-invasive facilities for pharmacological stress tests. SUBJECTS: 27 patients, mean (SD) age 60 (8) years, with documented evidence of coronary artery disease in whom dobutamine stress echo was clinically indicated, and 17 controls of similar age. RESULTS: In controls, all ECG intervals shortened with increasing heart rate but in the patient group only PR and QT intervals shortened while QRS duration broadened and QTc interval prolonged progressively. In the 27 patients, 16 developed chest pain, 15 with reduced left ventricular long axis systolic excursion (p < 0.001), and all showed reduced peak lengthening rate; ST segment shift appeared in 16, 13 of whom developed chest pain, but did not correlate with reduction of either systolic long axis excursion or peak lengthening rate; QRS duration broadened in 20, 16 with reduction of long axis excursion (p < 0.02) which was more often seen at the septum (p < 0.005); QTc interval prolonged in 19, all of whom had associated reduction of peak long axis lengthening rate (p < 0.02). CONCLUSIONS: QRS duration and QTc interval both normally shorten with dobutamine stress, while in coronary artery disease they both lengthen: changes in QRS duration correlate with systolic and QTc interval with diastolic left ventricular wall motion disturbances. ST segment shift also occurred in most patients, but without consistent correlation with wall motion abnormalities. It was thus less discriminating than the other two abnormalities in this respect.

Aged↗
PubMed1997

Value of natriuretic peptides in assessment of patients with possible new heart failure in primary care.

BACKGROUND: The reliability of a clinical diagnosis of heart failure in primary care is poor. Concentrations of natriuretic peptides are high in heart failure. This population-based study examined the predictive value of natriuretic peptides in patients with a new primary-care diagnosis of heart failure. METHODS: Concentrations of plasma atrial (ANP and N-terminal ANP) and B-type (BNP) natriuretic peptides were measured by radioimmunoassay in 122 consecutive patients referred to a rapid-access heart-failure clinic with a new primary-care diagnosis of heart failure. On the basis of clinical assessment, chest radiography, and transthoracic echocardiography, a panel of three cardiologists decided that 35 (29%) patients met the case definition for new heart failure. ANP and NT-ANP results were available for 117 patients (34 with heart failure) and BNP results for 106 (29 with heart failure). FINDINGS: Geometric mean concentrations of natriuretic peptides were much higher in patients with heart failure than in those with other diagnoses (29.2 vs 12.4 pmol/L for ANP; 63.9 vs 13.9 pmol/L for BNP; 1187 vs 410.6 pmol/L for NT-ANP; all p < 0.001). At cut-off values chosen to give negative predictive values for heart failure of 98% (ANP > or = 18.1 pmol/L, NT-ANP > or = 537.6 pmol/L, BNP > or = 22.2 pmol/L), the sensitivity, specificity, and positive predictive value for ANP were 97%, 72%, and 55%; for NT-ANP 97%, 66%, and 54%; and for BNP 97%, 84%, and 70%. Addition of ANP or NT-ANP concentration or both did not improve the predictive power of a logistic regression model containing BNP concentration alone. INTERPRETATION: In patients with symptoms suspected by a general practitioner to be due to heart failure, plasma BNP concentration seems to be a useful indicator of which patients are likely to have heart failure and require further clinical assessment.

Adult↗
PubMed1997

Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly.

OBJECTIVES: We sought to identify the pattern of disturbed left ventricular physiology associated with symptom development in elderly patients with effort-induced breathlessness. BACKGROUND: Limitation of exercise tolerance by dyspnea is common in the elderly and has been ascribed to diastolic dysfunction when left ventricular cavity size and systolic function appear normal. METHODS: Dobutamine stress echocardiography was used in 30 patients (mean [+/-SD] age 70 +/- 12 years; 21 women, 9 men) with exertional dyspnea and negative exercise test results, and the values were compared with those in 15 control subjects. RESULTS: Before stress, left ventricular end-diastolic and end-systolic dimensions were reduced, fractional shortening was increased, and the basal septum was thickened (2.3 +/- 0.5 vs. 1.4 +/- 0.2 cm, p < 0.001, vs. control subjects) in the patients, but posterior wall thickness did not differ from that in control subjects. Left ventricular outflow tract diameter, measured as systolic mitral leaflet septal distance, was significantly reduced (13 +/- 4.5 vs. 18 +/- 2 mm, p < 0.001). Isovolumetric relaxation time was prolonged, and peak left ventricular minor axis lengthening rate was reduced (8.1 +/- 3.5 vs. 10.4 +/- 2.6 cm/s, p < 0.05), suggesting diastolic dysfunction. Transmitral velocities and the E/A ratio did not differ significantly. At peak stress, heart rate increased from 66 +/- 8 to 115 +/- 20 beats/min in the control subjects, but blood pressure did not change. Transmitral A wave velocity increased, but the E/A ratio did not change. Left ventricular outflow tract velocity increased from 0.8 +/- 0.1 to 2.0 +/- 0.2 m/s, and mitral leaflet septal distance decreased from 18 +/- 2 to 14 +/- 3 mm, p < 0.001. In the patients, heart rate rose from 80 +/- 12 to 132 +/- 26 beats/min and systolic blood pressure from 143 +/- 22 to 170 +/- 14 mm Hg (p < 0.001 for each), but left ventricular dimensions did not change. Peak left ventricular outflow tract velocity increased from 1.5 +/- 0.5 m/s (at rest) to 4.2 +/- 1.2 m/s; mitral leaflet septal distance fell from 13 +/- 4.5 to 2.2 +/- 1.9 mm (p < 0.001); and systolic anterior motion of mitral valve appeared in 24 patients (80%) but in none of the control subjects (p < 0.001). Measurements of diastolic function did not change. All patients developed dyspnea at peak stress, but none developed a new wall motion abnormality or mitral regurgitation. CONCLUSIONS: Although our patients fulfilled the criteria for "diastolic heart failure," diastolic dysfunction was not aggravated by pharmacologic stress. Instead, high velocities appeared in the left ventricular outflow tract and were associated with basal septal hypertrophy and systolic anterior motion of the mitral valve. Their appearance correlated closely with the development of symptoms, suggesting a potential causative link.

Aged↗