***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Atrial and brain natriuretic peptides ( ANP and BNP ) are produced by the heart , and their plasma concentrations are increased in human chronic congestive heart failure . Although separate studies have suggested that circulating levels of the biologically active C-terminal ANP , the biologically inactive N-terminal ANP , and BNP may have diagnostic utility in the detection of left ventricular systolic dysfunction or left ventricular hypertrophy , no studies have directly assessed the relative value of these peptides prospect ively . We therefore design ed this study to compare the relative ability of the different natriuretic peptides to detect abnormal left ventricular systolic and diastolic function and left ventricular hypertrophy . Using a prospect i ve study design , we investigated 94 patients referred for cardiac catheterization and 15 age-matched normal subjects . The diagnostic abilities of elevated plasma C-terminal ANP , N-terminal ANP-(1 - 30 ) , and BNP concentrations to identify systolic dysfunction ( ejection fraction < 45 % ) , diastolic dysfunction ( time constant of left ventricular relaxation > 55 milliseconds , left ventricular end-diastolic pressure > 18 mm Hg ) , and left ventricular hypertrophy ( left ventricular mass index > 120 g/m2 ) were objective ly compared by receiver operating characteristic analysis . The areas under the receiver operating characteristic curve of BNP for detecting each of these abnormalities ranged from 0.715 to 0.908 and were significantly greater than those of C-terminal ANP or N-terminal ANP-(1 - 30 ) . The sensitivity and specificity of an elevated plasma BNP , which we defined as greater than the mean + 3 SD of the 15 age-matched normal subjects , were 0.83 and 0.77 , respectively , for detecting ejection fraction less than 45 % , 0.85 and 0.70 for detecting the time constant of left ventricular relaxation greater than 55 milliseconds , 0.63 and 0.76 for detecting left ventricular end-diastolic pressure greater than 18 mm Hg , and 0.81 and 0.85 for detecting left ventricular mass index greater than 120 g/m2 . The use of BNP and one other peptide increased sensitivity ( 0.90 to 0.96 ) , albeit with lower specificity ( 0.56 to 0.71 ) . An elevated plasma BNP was a more powerful marker of left ventricular systolic dysfunction , left ventricular diastolic dysfunction , and left ventricular hypertrophy than C-terminal ANP or N-terminal ANP-(1 - 30 ) in this population of patients with suspected cardiac disease . Measurement of BNP alone or in combination with C-terminal ANP or N-terminal ANP-(1 - 30 ) has potential utility for the detection of altered left ventricular structure and function in a patient population at risk for cardiovascular disease To determine the clinical value of simple , widely available variables in estimating left ventricular ( LV ) function , we performed an analysis on 14,507 patients presenting with chest pain who were enrolled in the Coronary Artery Surgery Study registry . Of these patients , 4,034 had a normal electrocardiogram  , and of these , 91.8 % had an LV ejection fraction ( EF ) > 0.50 , 7.6 % had an EF of 0.36 to 0.50 , and only 0.6 % had an EF < or = 0.35 . The presence of T-wave abnormalities ( with normal QRS ) , left bundle branch block , electrocardiographic evidence of LV hypertrophy or myocardial infa rct ion , cardiomegaly on chest roentgenogram , basilar rales , or third heart sound significantly decreased the likelihood of normal LVEF . Based on these clinical variables , a logistic regression model with a sensitivity of 68 % and a specificity of 74 % for identifying subjects with normal EF was developed . It was concluded that in patients with chest pain , consideration of such readily available clinical data provides useful information and may decrease the need for more expensive imaging methods 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 r and omly selected general and high risk community population s. Design : Community cohort study ( sub study of the echocardiographic heart of Engl and screening study ) . Setting : Four r and omly selected general practice s in the West Midl and s of Engl and . Participants : 591 r and omly sample d 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 population s 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 assay 's 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 INTRODUCTION The diagnosis of chronic heart failure ( CHF ) is based on demonstrating the cardiac origin of clinical manifestations . Echocardiography is the method of choice for the detection of left ventricular systolic dysfunction ( LVSD ) . Brain natriuretic peptide ( BNP ) rises during LVSD . OBJECTIVES To analyze the plasma concentration of N-terminal brain natriuretic propeptide ( NTproBNP ) in a general adult population in relation to different spontaneous circumstances and to study its capacity for identifying patients with LVSD . Methods . A cardiological examination was made and plasma NTproBNP levels were measured in a r and omized group of 203 people ( 49 - 81 years old ) from the Community of Valencia . RESULTS The average NTproBNP concentration was 52.2 98.2 pmol/l . NTproBNP levels varied with age , gender and functional stage ( NYHA ) . The highest NTproBNP values were observed in people who had previously suffered from acute pulmonary edema or who had an ejection fraction ( EF ) of less than 40 % . There was also a significant elevation in patients with nocturnal dyspnea , orthopnea , atrial fibrillation , EF < or = 50 % , angina , and ankle edema . The best concentration of NTproBNP for differentiating EF < or = 50 % was 37.7 pmol/l , with 92 % sensitivity and 68 % specificity . CONCLUSIONS The elevation of NTproBNP concentration indicates the cardiac origin of clinical manifestations and serves to select patients for echocardiographic examination . Low NTproBNP concentrations help to rule out LVSD BACKGROUND The aim of the study was to prospect ively evaluate patients with suspected or known heart disease using plasma brain natriuretic peptide ( BNP ) measurement and radionuclide ventriculography to examine whether left ventricular dysfunction is associated with an abnormal rise of BNP concentration . METHODS Patients ( n=153 ) and controls ( n=14 ) underwent radionuclide ventriculography to determine Left ventricular Ejection Fraction ( LVEF ) and measurement of plasma BNP concentration using a commercial kit . RESULTS Plasma BNP concentration in controls was significantly lower than that in patients whatever the stage of the disease , significantly lower than that of patients with normal LVEF ( LVEF>55 % ) ; than that of patients with altered LVEF ( LVEF < or = 40 % ) ; and than that of patients with moderately reduced LVEF ( 40%<LVEF < or = 5 % ) . Comparisons between groups of patients showed that the more severe the disease , the higher the BNP level . From the ROC curve , a plasma BNP concentration of 52 pg/ml was attached to a 85 % sensitivity and 82 % specificity in identifying patients with LVEF < or = 40 % . CONCLUSIONS Plasma BNP concentration provides a reliable and sensitive marker of LV systolic dysfunction evaluated by a nuclear medicine technique , and could be a potential screening test to identify patients for additional investigations The objective was to prospect ively vali date a method of increasing the sensitivity , specificity and negative predictive value of a normal ECG in the exclusion of left ventricular systolic dysfunction by the addition of clinical history . We performed a prospect i ve three year study of all referrals to our direct access ECHO service for assessment of LV function .  The ECG was reported blind of the result of the ECHO , history of MI or not was noted , and result of the ECHO predicted . Over three years 416 patients were assessed for the presence or absence of left ventricular systolic dysfunction and consequent changes in clinical management . A total of 320(77 % ) of patients referred with suspected left ventricular dysfunction were found to have normal left ventricular function . Of the 250(60 % ) patients treated prior to referral for assessment , 183(73 % ) were treated inappropriately . The combination of a normal ECG and a negative history of myocardial infa rct ion had a sensitivity of 98 % and a negative predictive value of 99 % in the assessment of LV function . This was an improvement over a normal ECG alone . Our study shows that diagnosis and treatment of heart failure in the community remains sub-optimal . The combination of a normal ECG and no previous history of myocardial infa rct ion is shown to be a sensitive and accurate predictor of normal left ventricular function . If adopted by general practitioners this would be a valuable method of optimising the use of ECHOCARDIOGRAPHIC in patients with suspected left ventricular dysfunction 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 Engl and . METHODS Of 6286 r and omly selected patients aged 45 years and older , 3960 ( 63 % ) participated in the study . They came from 16 r and omly selected general practice s. 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 OBJECTIVES The purpose of this study was to determine the effect of amino-terminal pro-brain natriuretic peptide ( N-BNP ) on the diagnostic accuracy of heart failure ( HF ) in primary care . BACKGROUND The accurate diagnosis of patients with suspected HF presenting in primary care is difficult . Amino-terminal pro-brain natriuretic peptide is present in high levels in cardiac dysfunction and may improve the diagnostic accuracy of HF in primary care . METHODS The Natriuretic Peptides in the Community Study was a prospect i ve , r and omized controlled trial of the effect of N-BNP on the accuracy of HF diagnosis . Patients presenting to their general practitioner ( GP ) with symptoms of dyspnea and /or peripheral edema were included . The GPs formulated an initial diagnosis based on clinical assessment . All patients underwent a full cardiologic assessment that included echocardiography and N-BNP . Each patient was r and omized to the BNP group ( GP received the N-BNP result ) or the control group ( GP did not receive the N-BNP result ) . Patients were then review ed by their GP , and their diagnosis was review ed . The primary end 
    Output:
    
On the basis of existing evidence , the ECG , BNP and NT-proBNP are useful in excluding a diagnosis of LVSD ( good sensitivity ) .
There is currently no evidence to justify the use of one test over another or the use of tests in combination .