J E Kenkre

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.

Prevalence of atrial fibrillation in the general population and in high-risk groups: the ECHOES study

AIMS To establish the prevalence of atrial fibrillation (AF) in the general population in the UK, and in those with risk factors. METHODS AND RESULTS The prevalence of AF on electrocardiography was established in prospectively selected groups: 3960 randomly selected from the population, aged 45+; 782 with a previous diagnosis of heart failure; and 1062 with a record of myocardial infarction, hypertension, angina, or diabetes. Patients were also assessed clinically and with echocardiography. Mortality was tracked for 8 years. Atrial fibrillation was found in 78 of the random population sample (2.0%). Prevalence was 1.6% in women and 2.4% in men, rising with age from 0.2% in those aged 45-54 to 8.0% in those aged 75 and older. Half of all cases were in patients aged 75 and older. Only 23 of the 78 (29.5%) of those in AF took warfarin. Of the 782 patients, 175 (22.4%) with a diagnosis of heart failure were in AF, with normal left ventricular function in 95 (54.3%) of these. Atrial fibrillation was found in 14 of the 244 (5.7%) of those with a history of myocardial infarction, 15 of the 388 (3.9%) of those with hypertension, 15 of the 321 (4.7%) of those with angina, and 11 of the 208 (5.3%) of diabetics. Adjusting for age and sex, mortality was 1.57 times higher for those in AF. CONCLUSION Atrial fibrillation is common in the elderly and those with clinical risk factors. Screening these groups would identify many with AF. Use of anticoagulation was low at the time of the initial assessments in the late 1990s; practice may have changed recently.

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.