***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: Background —It is often difficult to diagnose heart failure ( HF ) accurately in patients presenting with dyspnea to the emergency department ( ED ) . This study assessed whether B-type natriuretic peptide ( BNP ) testing in these patients improved the accuracy of HF diagnosis . Methods and Results — Patients presenting to the Alfred and the Northern Hospital EDs with a chief complaint of dyspnea were enrolled prospect ively from August 2005 to April 2007 . Patients were r and omly allocated to have BNP levels tested or not . The diagnostic gold st and ard for HF was determined by 1 cardiologist and 1 emergency or respiratory physician who , blinded to the BNP result , independently review ed all available information . The ED diagnosis of HF in the non-BNP group showed a sensitivity , specificity , and accuracy of 65 % , 92 % , and 81 % , respectively . The BNP group had a similar sensitivity , specificity , and accuracy of 66 % , 90 % , and 78 % , respectively , for the diagnosis of HF in the ED . There was no significant difference between the BNP and non-BNP groups in any of the measures of diagnostic accuracy for HF . Conclusion —In the clinical setting of EDs , availability of BNP levels did not significantly improve the accuracy of a diagnosis of HF . Clinical Trial Registration — clinical trials.gov . Identifier : NCT00163709 BACKGROUND The purpose of this study was to determine the diagnostic power of a newly available assay for amino-terminal pro-brain natriuretic peptide ( NT-proBNP ) to identify patients with acute heart failure . In addition , the influence of initial NT-proBNP measurements on economic consequences , diagnostic procedures and staff involvement was evaluated . METHODS AND RESULTS 401 patients presenting with acute dyspnea or peripheral edema in the emergency department were enrolled .  NT-proBNP was measured after initial clinical evaluation . Clinical routine care and diagnostic assessment were blinded to NT-proBNP results . Two cardiologists independently vali date d the period of hospitalization , clinical examinations and medical therapies of each patient considering NT-proBNP results . The median NT-proBNP level among patients with acute congestive heart failure ( CHF ) ( n=122 ) was 3497 pg/ml as compared to 320 pg/ml in patients without ( n=279 ) ( p<0.0001 ) . An NT-proBNP cutoff level < 300 pg/ml was optimal to rule out acute CHF ( negative predictive value 96 % ; sensitivity 96 % ) . NT-proBNP > or=300 pg/ml could strongly predict acute CHF when compared to patients ' history or physical examination ( odds ratio 9.5 ; p<0.0001 ) and diagnostic technical findings ( odds ratio 14.7 ; p<0.05 ) . In patients with NT-proBNP<300 pg/ml , 14 % of the period of hospitalization could be saved , corresponding to savings of US $ 481 per patient . In addition , 9 % of the number and time of staff involvement of clinical examinations and therapies could be saved , 10 % of the costs of clinical examinations . Chest X-rays were saved in 34 % , echocardiography in 9 % . CONCLUSIONS Measurement of NT-proBNP leads to multiple saving amounts and optimizes diagnostic pathways and re source allocation BACKGROUND The incremental role of bedside tissue Doppler echocardiography and B-type natriuretic peptide ( BNP ) over the clinical judgment has been recently reported in the emergency diagnosis of congestive heart failure with a normal left ventricular ejection fraction ( HFNEF ) . However , how well does this diagnostic strategy be applicable in the setting of atrial fibrillation is unknown . OBJECTIVE To investigate the usefulness of bedside tissue Doppler echocardiography and BNP in the emergency diagnosis of HFNEF in elderly patients with permanent , nonvalvular atrial fibrillation . METHODS Forty-one consecutive elderly patients with an ejection fraction > or = 50 % ( mean age 84 years ; 22 with HFNEF and 19 with noncardiac cause ) , hospitalized for acute dyspnea at rest , were prospect ively enrolled ; bedside septal E/Ea and BNP were obtained at admission . RESULTS By multivariable logistic regression analysis including the clinical judgment of heart failure , E/Ea and BNP , E/Ea ( P = 0.014 ) and BNP ( P = 0.018 ) provided independent diagnostic information . Optimal cutoffs were 13 for E/Ea ( area under the ROC curve of 0.846 , P < 0.0001 ; sensitivity 81.8 % , specificity 89.5 % ) and 253 pg/ml for BNP ( area under the ROC curve of 0.928 , P < 0.0001 ; sensitivity 86.4 % , specificity 89.5 % ) . The concordance between the clinical judgment and BNP concentration at the cutoff of 253 pg/ml correctly classified 24 of 25 patients ; E/Ea at the cutoff of 13 correctly classified 14 of the 16 patients with discrepancy . CONCLUSION Bedside tissue Doppler echocardiography and BNP provide useful additional diagnostic information over the clinical judgment for the emergency diagnosis of HFNEF in elderly patients with permanent , nonvalvular atrial fibrillation Introduction We studied the diagnostic accuracy of bedside lung ultrasound ( the presence of a comet-tail sign ) , N-terminal pro-brain natriuretic peptide ( NT-proBNP ) and clinical assessment ( according to the modified Boston criteria ) in differentiating heart failure (HF)-related acute dyspnea from pulmonary ( chronic obstructive pulmonary disease ( COPD ) /asthma)-related acute dyspnea in the prehospital setting . Methods Our prospect i ve study was performed at the Center for Emergency Medicine , Maribor , Slovenia , between July 2007 and April 2010 . Two groups of patients were compared : a HF-related acute dyspnea group ( n = 129 ) and a pulmonary ( asthma/ COPD ) -related acute dyspnea group ( n = 89 ) . All patients underwent lung ultrasound examinations , along with basic laboratory testing , rapid NT-proBNP testing and chest X-rays . Results The ultrasound comet-tail sign has 100 % sensitivity , 95 % specificity , 100 % negative predictive value ( NPV ) and 96 % positive predictive value ( PPV ) for the diagnosis of HF . NT-proBNP ( cutoff point 1,000 pg/mL ) has 92 % sensitivity , 89 % specificity , 86 % NPV and 90 % PPV . The Boston modified criteria have 85 % sensitivity , 86 % specificity , 80 % NPV and 90 % PPV . In comparing the three methods , we found significant differences between ultrasound sign and ( 1 ) NT-proBNP ( P < 0.05 ) and ( 2 ) Boston modified criteria ( P < 0.05 ) . The combination of ultrasound sign and NT-proBNP has 100 % sensitivity , 100 % specificity , 100 % NPV and 100 % PPV . With the use of ultrasound , we can exclude HF in patients with pulmonary-related dyspnea who have positive NT-proBNP ( > 1,000 pg/mL ) and a history of HF . Conclusions An ultrasound comet-tail sign alone or in combination with NT-proBNP has high diagnostic accuracy in differentiating acute HF-related from COPD /asthma-related causes of acute dyspnea in the prehospital emergency setting .Trial registration Clinical Trials.gov NCT01235182 The utility of aminoterminal pro-brain natriuretic peptide ( NT-proBNP ) testing in the emergency department to rule out acute congestive heart failure ( CHF ) and the optimal cutpoints for this use are not established . We conducted a prospect i ve study of 600 patients who presented in the emergency department with dyspnea . The clinical diagnosis of acute CHF was determined by study physicians who were blinded to NT-proBNP results . The primary end point was a comparison of NT-proBNP results with the clinical assessment of the managing physician for identifying acute CHF . The median NT-proBNP level among 209 patients ( 35 % ) who had acute CHF was 4,054 versus 131 pg/ml among 390 patients ( 65 % ) who did not ( p < 0.001 ) . NT-proBNP at cutpoints of > 450 pg/ml for patients < 50 years of age and > 900 pg/ml for patients > or=50 years of age were highly sensitive and specific for the diagnosis of acute CHF ( p < 0.001 ) . An NT-proBNP level < 300 pg/ml was optimal for ruling out acute CHF , with a negative predictive value of 99 % . Increased NT-proBNP was the strongest independent predictor of a final diagnosis of acute CHF ( odds ratio 44 , 95 % confidence interval 21.0 to 91.0 , p < 0.0001 ) . NT-proBNP testing alone was superior to clinical judgment alone for diagnosing acute CHF ( p = 0.006 ) ; NT-proBNP plus clinical judgment was superior to NT-proBNP or clinical judgment alone . NT-proBNP measurement is a valuable addition to st and ard clinical assessment for the identification and exclusion of acute CHF in the emergency department setting INTRODUCTION The aim of this study was to evaluate the role of cardiac ultrasound in diagnosing acute heart failure ( AHF ) in patients with acute dyspnea with available plasma B-type natriuretic peptide ( BNP ) level . METHODS Patients with acute dyspnea presenting to the emergency department ( ED ) of a tertiary medical center were prospect ively enrolled . The enrolled 84 patients received both BNP tests and cardiac ultrasound studies and were classified into AHF and non-heart failure groups . RESULTS Plasma BNP levels were higher in the AHF group ( 1236 ± 1123 vs 354 ± 410 pg/mL ; P < .001 ) . The AHF group had larger left ventricular end-diastolic dimension ( LVEDD ; 32 ± 7 vs 27 ± 4 mm/m(2 ) ; P < .001 ) and worse left ventricular ejection fraction ( 52 % ± 18 % vs 64 % ± 15 % ; P = .003 ) . Multiple logistic regression analysis showed that both BNP levels more than 100 pg/mL and LVEDD were independent predictors for AHF . In patients with plasma BNP levels within gray zone of 100 to 500 pg/mL , LVEDD was larger in the AHF group than that in the non-heart failure group ( 29 ± 4 vs 26 ± 4 mm/m(2 ) ; P = .044 ) . CONCLUSION Both LVEDD by cardiac ultrasound and BNP levels can help emergency physicians independently diagnose AHF in the ED . In patients with plasma BNP levels within 100 to 500 pg/mL , cardiac ultrasound can help differentiate heart failure or not Objective Differentiating cardiogenic pulmonary edema ( CPE ) from respiratory causes of dyspnea is particularly difficult in elderly patients . The aim of our study was to evaluate B-type natriuretic peptide ( BNP ) in patients older than 65 years presenting with acute dyspnea . Design Prospect i ve study . Setting Medical emergency department of a 2000-bed urban teaching hospital . Patients Patients aged over 65 years presenting with acute dyspnea and a respiratory rate more than 25/min or a PaO2 below 70 mmHg , SpO2 less than 92 % , PaCO2 higher than 45 mmHg with pH less than 7.35 , were included .  BNP levels , measured blind at admission were compared with the final diagnosis ( CPE or no CPE ) as defined by experts . InterventionNone . Measurements and results Three hundred eight patients ( mean age of 80 years ) were enrolled in the study . The median BNP was 575 pg/ml [ 95 % confidence interval ( CI ) : 410–898 ] in the CPE group ( n=141 ) versus 75 pg/ml ( 95 % CI : 59–98 ) in the no CPE group ( n=167 ) ( p<0.001 ) . The best threshold value of BNP was 250 pg/ml , with a sensitivity and specificity for CPE of 0.78 ( 95 % CI : 0.71–0.84 ) and 0.90 ( 95 % CI : 0.84–0.93 ) , respectively . The area under the ROC curve was 0.874±0.081 ( p<0.001 ) . The accuracy of BNP-assisted diagnosis was higher than that of the emergency physician ( 0.84 versus 0.77 , p<0.05 ) . Conclusion Analysis of B 
    Output:
    
Both BNP and NT-proBNP perform well to rule out , but less well to rule in , the diagnosis of heart failure among persons presenting to emergency departments or urgent care centers .
Both BNP and NT-proBNP levels are positively associated with age and negatively associated with renal function .
However , the effect of these factors with respect to selecting optimal cutpoints is unclear .
For BNP , 100 pg/mL appears to be a consensus cutpoint .