Michael K. Davies

Prevalence of left-ventricular systolic dysfunction and heart failure in the Echocardiographic Heart of England Screening study: a population based study

BACKGROUND Accurate data for prevalence rates for heart failure due to various causes, and for left-ventricular systolic dysfunction in all adults are unavailable. Our aim was to assess prevalence of left-ventricular systolic dysfunction and heart failure in a large representative adult population in England. METHODS Of 6286 randomly selected patients aged 45 years and older, 3960 (63%) participated in the study. They came from 16 randomly selected general practices. We assessed patients by history and examination, electrocardiography, and echocardiography. Prevalence of left-ventricular systolic dysfunction (defined as ejection fraction <40%) and heart failure was calculated for the overall population on the basis of strict criteria and, when necessary, adjudication by a panel. FINDINGS Left-ventricular systolic dysfunction was diagnosed in 72 (1.8% [95% CI 1.4-2.3]) participants, half of whom had no symptoms. Borderline left-ventricular function (ejection fraction 40-50%) was seen in 139 patients (3.5% [3.0-4.1]). Definite heart failure was seen in 92 (2.3%, [1.9-2.8]) and was associated with an ejection fraction of less than 40% in 38 (41%) patients, atrial fibrillation in 30 (33%), and valve disease in 24 (26%). Probable heart failure was seen in a further 32 (0.8% [0.6-1.1]) patients. In total, 124 (3.1% [2.6-3.7]) patients aged 45 years or older had definite or probable heart failure. INTERPRETATION Heart failure is often misdiagnosed or underdiagnosed in primary care. Our results suggest that assessment of left-ventricular function in patients with suspected heart failure could lead to more effective diagnosis and treatment of this disorder.

Screening versus routine practice in detection of atrial fibrillation in patients aged 65 or over: cluster randomised controlled trial

Objectives To assess whether screening improves the detection of atrial fibrillation (cluster randomisation) and to compare systematic and opportunistic screening. Design Multicentred cluster randomised controlled trial, with subsidiary trial embedded within the intervention arm. Setting 50 primary care centres in England, with further individual randomisation of patients in the intervention practices. Participants 14 802 patients aged 65 or over in 25 intervention and 25 control practices. Interventions Patients in intervention practices were randomly allocated to systematic screening (invitation for electrocardiography) or opportunistic screening (pulse taking and invitation for electrocardiography if the pulse was irregular). Screening took place over 12 months in each practice from October 2001 to February 2003. No active screening took place in control practices. Main outcome measure Newly identified atrial fibrillation. Results The detection rate of new cases of atrial fibrillation was 1.63% a year in the intervention practices and 1.04% in control practices (difference 0.59%, 95% confidence interval 0.20% to 0.98%). Systematic and opportunistic screening detected similar numbers of new cases (1.62% v 1.64%, difference 0.02%, −0.5% to 0.5%). Conclusion Active screening for atrial fibrillation detects additional cases over current practice. The preferred method of screening in patients aged 65 or over in primary care is opportunistic pulse taking with follow-up electrocardiography. Trial registration Current Controlled Trials ISRCTN19633732.

Reliability of N-terminal pro-brain natriuretic peptide assay in diagnosis of heart failure: cohort study in representative and high risk community populations.

Abstract Objective: To investigate the performance of a novel assay for N-terminal pro-brain natriuretic peptide (NT-proBNP) in diagnosing heart failure in various randomly selected general and high risk community populations. Design: Community cohort study (substudy of the echocardiographic heart of England screening study). Setting: Four randomly selected general practices in the West Midlands of England. Participants: 591 randomly sampled patients over the age of 45, stratified for age and socioeconomic status and falling into four cohorts (general population, patients with an existing clinical label of heart failure, patients prescribed diuretics, and patients deemed at high risk of heart failure). Main outcome measure: Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and area under receiver operating characteristic curve for NT-proBNP assay in the diagnosis of heart failure. Results: For NT-proBNP in the diagnosis of heart failure in the general population (population screen), a level of >36 pmol/l had a sensitivity of 100%, a specificity of 70%, a positive predictive value of 7%, a negative predictive value of 100%, and an area under the receiver operating characteristic curve of 0.92 (95% confidence interval 0.82 to 1.0). Similar negative predictive values were found for patients from the three other populations screened. Conclusions: This NT-proBNP assay seems to have value in the diagnosis of heart failure in the community. High negative predictive values indicate that the assays chief use would be to rule out heart failure in patients with suspected heart failure with normal concentrations of NT-proBNP. Positive results may identify patients who need cardiac imaging.

Reliability of N-terminal proBNP assay in diagnosis of left ventricular systolic dysfunction within representative and high risk populations

Objective: To determine the performance of a new NT-proBNP assay in comparison with brain natriuretic peptide (BNP) in identifying left ventricular systolic dysfunction (LVSD) in randomly selected community populations. Methods: Blood samples were taken prospectively in the community from 591 randomly sampled individuals over the age of 45 years, stratified for age and socioeconomic status and divided into four cohorts (general population; clinically diagnosed heart failure; patients on diuretics; and patients deemed at high risk of heart failure). Definite heart failure (left ventricular ejection fraction (LVEF) < 40%) was identified in 33 people. Samples were handled as though in routine clinical practice. The laboratories undertaking the assays were blinded. Results: Using NT-proBNP to diagnose LVEF < 40% in the general population, a level of > 40 pmol/l had 80% sensitivity, 73% specificity, 5% positive predictive value (PPV), 100% negative predictive value (NPV), and an area under the receiver-operator characteristic curve (AUC) of 76% (95% confidence interval (CI) 46% to 100%). For BNP to diagnose LVSD, a cut off level of > 33 pmol/l had 80% sensitivity, 88% specificity, 10% PPV, 100% NPV, and AUC of 88% (95% CI 75% to 100%). Similar NPVs were found for patients randomly screened from the three other populations. Conclusions: Both NT-proBNP and BNP have value in diagnosing LVSD in a community setting, with similar sensitivities and specificities. Using a high cut off for positivity will confirm the diagnosis of LVSD but will miss cases. At lower cut off values, positive results will require cardiac imaging to confirm LVSD.

Prevalence of left ventricular systolic dysfunction and heart failure in high risk patients: community based epidemiological study

abstract Objectives: To determine the prevalence of left ventricular systolic dysfunction, and of heart failure due to different causes, in patients with risk factors for these conditions. Design: Epidemiological study, including detailed clinical assessment, electrocardiography, and echocardiography. Setting: 16 English general practices, representative for socioeconomic status and practice type. Participants: 1062 patients (66% response rate) with previous myocardial infarction, angina, hypertension, or diabetes. Main outcome measures: Prevalence of systolic dysfunction, both with and without symptoms, and of heart failure, in groups of patients with each of the risk factors. Results: Definite systolic dysfunction (ejection fraction <40%) was found in 54/244 (22.1%, 95% confidence interval 17.1% to 27.9%) patients with previous myocardial infarction, 26/321 (8.1%, 5.4% to 11.6%) with angina, 7/388 (1.8%, 0.7% to 3.7%) with hypertension, and 12/208 (5.8%, 3.0% to 9.9%) with diabetes. In each group, approximately half of these patients had symptoms of dyspnoea, and therefore had heart failure. Overall rates of heart failure, defined as symptoms of dyspnoea plus objective evidence of cardiac dysfunction (systolic dysfunction, atrial fibrillation, or clinically significant valve disease) were 16.0% (11.6% to 21.2%) in patients with previous myocardial infarction, 8.4% (5.6% to 12.0%) in those with angina, 2.8% (1.4% to 5.0%) in those with hypertension, and 7.7% (4.5% to 12.2%) in those with diabetes. Conclusion: Many people with ischaemic heart disease or diabetes have systolic dysfunction or heart failure. The data support the need for trials of targeted echocardiographic screening, in view of the major benefits of modern treatment. In contrast, patients with uncomplicated hypertension have similar rates to the general population.

Left ventricular ejection fraction: are the revised cut-off points for defining systolic dysfunction sufficiently evidence based?

The recent guidelines from the American Society of Echocardiography and European Society of Echocardiography have defined an abnormal ejection fraction (EF) of the left ventricle, as one that is <55%.1 Owing to the fact that it is a continuous biological variable, there is inevitable debate over what constitutes mild, moderate and severe left ventricular (LV) dysfunction across the ranges of EF. Up to now, the lower limit of normal in clinical practice has usually been set at 40%.2 Despite the recent guidelines,1 there has been little debate or evidence to suggest altering the lower limit of normality to include patients with EFs of 50–54%. These guidelines therefore represent a step change in the definition of (echocardiographic) LV systolic dysfunction and will include many more patients into the category of “impaired LV function” with EFs >50%. The main limitation of this approach is how best to define risk. The cut-off points suggested for a single parameter can vary broadly for the risk of death, myocardial infarction, congestive heart failure and atrial fibrillation. Also, much of the literature applies to specific populations (eg, after myocardial infarction, the elderly) and not to overall cardiovascular risk.1 The recommended new cut-off EF value of 54% is based on expert opinion, interpreting data from the limited number of studies that have reported that an EF <54% is associated with moderate adverse outcomes.1 For example, Roman et al followed up 486 patients undergoing echocardiography to determine the prevalence of carotid atherosclerosis and to examine its relationship to LV hypertrophy.3 Two hundred and seventy-seven subjects were normotensive and 209 subjects had untreated hypertension, and all were asymptomatic with no overt manifestations of cerebrovascular disease. The investigators found that 392 patients were essentially without any evidence of carotid plaques and 366 patients had …

Serum cortisol levels predict infarct size and patient mortality

We have investigated prospectively the serum cortisol response to acute myocardial infarction in 70 consecutive patients admitted to a coronary care unit and we have shown that the levels are significantly raised early in the course of the illness and prior to elevation of the cardiac specific enzyme fraction, creatine kinase MB. The magnitude of the cortisol response is related to the size of the ensuing infarction (rs = 0.54) as calculated from the total creatine kinase MB release (P < 0.001) and very high levels (> 2000 mumol/l) are predictive of mortality (P < 0.05). Serum cortisol levels may have a role in the early identification of myocardial infarction and in predicting those patients with a poor prognosis.

Home-based exercise rehabilitation in addition to specialist heart failure nurse care: design, rationale and recruitment to the Birmingham Rehabilitation Uptake Maximisation study for patients with congestive heart failure (BRUM-CHF): a randomised controlled trial

BackgroundExercise has been shown to be beneficial for selected patients with heart failure, but questions remain over its effectiveness, cost-effectiveness and uptake in a real world setting. This paper describes the design, rationale and recruitment for a randomised controlled trial that will explore the effectiveness and uptake of a predominantly home-based exercise rehabilitation programme, as well as its cost-effectiveness and patient acceptability.Methods/designRandomised controlled trial comparing specialist heart failure nurse care plus a nurse-led predominantly home-based exercise intervention against specialist heart failure nurse care alone in a multiethnic city population, served by two NHS Trusts and one primary care setting, in the United Kingdom.169 English speaking patients with stable heart failure, defined as systolic impairment (ejection fraction ≤ 40%). with one or more hospital admissions with clinical heart failure or New York Heart Association (NYHA) II/III within previous 24-months were recruited.Main outcome measures at 1 year: Minnesota Living with Heart Failure Questionnaire, incremental shuttle walk test, death or admission with heart failure or myocardial infarction, health care utilisation and costs. Interviews with purposive samples of patients to gain qualitative information about acceptability and adherence to exercise, views about their treatment, self-management of their heart failure and reasons why some patients declined to participate.The records of 1639 patients managed by specialist heart failure services were screened, of which 997 (61%) were ineligible, due to ejection fraction>40%, current NYHA IV, no admission or NYHA II or more within the previous 2 years, or serious co-morbidities preventing physical activity. 642 patients were contacted: 289 (45%) declined to participate, 183 (39%) had an exclusion criterion and 169 (26%) agreed to randomisation.DiscussionDue to safety considerations for home-exercise less than half of patients treated by specialist heart failure services were eligible for the study. Many patients had co-morbidities preventing exercise and others had concerns about undertaking an exercise programme.

ELIGIBILITY FOR THROMBOLYTIC THERAPY IN ACUTE MYOCARDIAL INFARCTION

In a district general hospitals coronary care unit (CCU) 197 patients with chest pain were admitted over a 6-month period and in 131 an acute myocardial infarction (AMI) was confirmed. 67 (51%) were eligible for thrombolytic therapy, on criteria laid down for a trial of streptokinase. Criteria for thrombolysis were not fulfilled in 41 (31%) and 12 patients (9%) had contraindications. These results suggest that around half of all patients with AMI and about one-third of patients presenting with chest pain and admitted to a CCU would be suitable for thrombolytic therapy. These data do not support the view that such therapy may be applicable to only a small minority of patients with AMI.

Management of chronic heart failure in the community: role of a hospital based open access heart failure service

Objective: To evaluate the role of an open access heart failure service based at a teaching hospital for the diagnosis and treatment optimisation of patients with heart failure in the community and to identify measures that may further enhance the effectiveness of such a service. Subjects: 963 patients with suspected heart failure seen over an eight year period referred by their general practitioners to the cardiology department at a district general hospital. Main outcome measures: Presence or absence of left ventricular systolic dysfunction (LVSD) (left ventricular ejection fraction < 50% on echocardiography), and determination of the risk factors and predictors of LVSD. Results: The majority of the patients were women (60% v 40%) and elderly (mean age 68.8 years). On echocardiography, only 30.8% were found to have LVSD. Patients were more likely to have LVSD if they were men (42.3% v 23.1%, p < 0.001, relative risk (RR) 1.8), were > 60 years of age (33.5% v 20.8%, p < 0.001, RR 1.6), or had a history of diabetes (49.4% v 29.1%, p < 0.001, RR 1.7), ischaemic heart disease (36.5% v 29.1%, p  =  0.04, RR 1.3), or atrial fibrillation (52.6% v 27.8%, p < 0.001, RR 1.9). An abnormal ECG (48.4% v 19.5%, p < 0.001, RR 2.5) and cardiothoracic ratio > 0.5 on chest radiograph (44.3% v 17.8%, p < 0.001, RR 2.5) were found to be good predictors of LVSD. A normal ECG (negative predictive value 80.5%) and a cardiothoracic ratio of < 0.5 (negative predictive value 82.2%) can be used as baseline measures to identify patients with lower risk of developing LVSD (combined negative predictive value 87.9%). Conclusions: An open access heart failure clinic is effective for the diagnosis and management of chronic heart failure in community based patients. The presence of risk factors and simple baseline tests can be used to identify patients with LVSD in the community. The introduction of a protocol based on these findings into a referral system can improve the efficiency and cost effectiveness of such a service.