***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: 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 BACKGROUND Diagnostic echocardiography has poor access for patients with suspected heart failure .  Pre-echocardiography screening with electrocardiograms ( ECGs ) is recommended as a means of targeting this scarce re source . There are data to support this policy when ECGs are interpreted by cardiologists but not by GPs . AIM To assess the value of GP-reported ECGs as a pre-echocardiography screening test for left ventricular systolic dysfunction ( LVSD ) . DESIGN OF STUDY Cross-sectional study of GPs ' ECG reporting skills . SETTING General practice , NHS in Scotl and . METHOD A r and omly selected , stratified sample of 123 Scottish GPs review ed 180 ECGs ( 100 abnormal , 50 normal and 30 duplicate ) from 150 patients with suspected heart failure . Forty-one patients had LVSD on echocardiography . GPs were required to categorise ECGs as normal or abnormal . RESULTS Mean sensitivity was 0.94 ( 95 % CI = 0.92 to 0.95 ) . Mean specificity 0.58 ( 95 % CI = 0.56 to 0.60 ) . Mean positive predictive value ( PPV ) was 0.47 ( 95 % CI = 0.46 to 0.48 ) . Mean negative predictive value ( NPV ) was 0.96 ( 95 % CI = 0.95 to 0.97 ) . Mean likelihood ratio was 2.39 ( 95 % CI = 2.28 to 2.50 ) . Seventy of 123 ( 57 % ) GPs achieved sensitivity of 0.9 and specificity of 0.5 for the detection of LVSD . CONCLUSION Most Scottish GPs have the skills to perform pre-echocardiography screening ECGs in patients with suspected LVSD . However , differences in ECG reporting performance between individual GPs will result in widely varying referral rates for echocardiography and differences in the detection rate of LVSD . The implication s of these findings need to be considered when heart failure diagnostic services are being developed BACKGROUND National guidelines suggest the use of natriuretic peptides in suspected heart failure but there have been no studies comparing assays in primary care . AIM To test and compare the diagnostic accuracy and utility of B-type natriuretic peptide ( BNP ) and N-terminal B-type natriuretic peptide ( NT proBNP ) in diagnosing heart failure due to left ventricular systolic dysfunction in patients with suspected heart failure referred by GPs to one-stop diagnostic clinics . DESIGN OF STUDY Community cohort , prospect i ve , diagnostic accuracy study . SETTING One-stop diagnostic clinics in Darlington Memorial and Bishop Auckl and General Hospitals and general practice s in South Durham . SUBJECTS Two hundred and ninety-seven consecutive patients with symptoms and signs suggestive of heart failure referred from general practice . METHOD The study measured sensitivity , specificity , positive and negative predictive values ( PPV , NPV ) , and area under receiver operating characteristic curve for BNP ( near patient assay ) and NT proBNP ( laboratory assay ) in diagnosis of heart failure due to left ventricular systolic dysfunction . The NPV of both assays was determined as a potential method of reducing the number of referrals for echocardiography . RESULTS One hundred and fourteen of the 297 patients had  left ventricular systolic dysfunction  ( 38 % ) . At the manufacturer 's recommended cut-off of 100 pg/ml BNP gave a NPV of 82 % . BNP performed better at a cut-off of 40 pg/ml with a NPV of 88 % . At a cut-off of 150 pg/ml , NT proBNP gave a NPV of 92 % . Using cut-offs of 40 pg/ml and 150 pg/ml for BNP and NT pro-BNP , respectively , could have prevented 24 % and 25 % of referrals to the clinic , respectively . CONCLUSIONS In this setting , NT pro-BNP performed marginally better than BNP , and would be easier to use practically in primary care . A satisfactory cut-off has been identified , which needs validating in general practice . NT pro-BNP could be used to select referrals to a heart failure clinic or for echocardiography . This process needs testing in real-life general practice BACKGROUND The early identification of patients at risk for the development of clinical heart failure ( HF ) is a new challenge in an effort to improve outcomes . METHODS We prospect ively evaluated whether the combination of brain natriuretic peptide ( BNP ) measurements ( Triage BNP test , Biosite Diagnostics ) and echocardiography would effectively stratify patients with new symptoms in a cost-effective HF program aim ed at early diagnosis of mild HF . A total of 252 patients were referred by 100 general practitioners . RESULTS Among the study population , the median BNP value was 78 ng/L ( range , 5 - 1491 ng/L ) . BNP concentrations were lower among patients without heart disease [ median 15 ng/L ( range , 5 - 167 ng/L ) ; n = 96 ] than among patients with confirmed HF [ median , 165 ng/L ( 22 - 1491 ng/L ) ; n = 157 ; Mann-Whitney U-test , 12.3 ; P < 0.001 ] . Patients were grouped into diastolic dysfunction [ BNP , 195 ( 223 ) ng/L ] , systolic dysfunction [ BNP , 290 ( 394 ) ng/L ] , and both systolic and diastolic dysfunction [ BNP , 776 ( 506 ) ng/L ] . In this model , a cutoff value of 50 ng/L BNP increases the diagnostic accuracy in predicting mild HF , avoiding 41 echocardiograms per 100 patients studied , with a net saving of 14 % of total costs . CONCLUSIONS Blood BNP concentrations , in a cost effective targeted screening , can play an important role in diagnosing mild HF and stratifying patients into risk groups of cardiac dysfunction BACKGROUND Diagnosing suspected left ventricular systolic dysfunction ( LVSD ) in the community is a challenge for GPs . We developed and vali date d a clinical prediction rule ( CPR ) for LVSD based on history , examination and electrocardiogram ( ECG ) . METHODS Prospect i ve cohort studies of 458 symptomatic patients ( derivation cohort ) and 535 patients ( validation cohort ) in 26 general practice s in Tayside and Fife , Scotl and . All patients underwent a structured clinical examination and ECG and the ' reference st and ard ' investigation of echocardiography to establish the presence of LVSD . RESULTS Four elements from the clinical history and examination were all independently associated with LVSD -- male sex [ adjusted odds ratio ( OR ) 2.5 ; 95 % CI 1.1 , 5.0 ] , presence of orthopnoea ( OR 5.4 ; 1.9 , 13.8 ) history of myocardial infa rct ion ( OR 5.6 ; 2.3 , 13.6 ) and elevated jugular venous pulsations ( OR 15.1 ; 4.6 , 49.3 ) . Addition of ECG ( OR 20.6 ; 2.7 , 158.6 ) provides important diagnostic information in terms of probability of LVSD . A CPR based on the presence or absence of these five elements will generate probabilities ranging from 1 % to 97 % for LVSD when applied to an individual patient . In the validation cohort , the model under-predicted the probability of LVSD , particularly at lower levels of expected risk , reflecting differences in the risk-factor profiles of the derivation and validation cohorts . CONCLUSIONS The derived CPR provides quantitative estimates of post-test probability for LVSD . This rule requires further validation in other population s and setting s because of the difficulties encountered in the validation cohort 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 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 BACKGROUND Although echocardiography is the gold 
    Output:
    
Conclusion Findings from the clinical history and examination are insufficient to " rule in " or " rule out " a diagnosis of LVSD in primary care setting s. BNP and ECG measurement appear to have similar diagnostic utility and are most useful in " ruling out " LVSD with a normal test result when the probability of LVSD is in the intermediate range