***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: The measurement of  plasma B-type natriuretic peptide ( BNP )  has emerged as a useful biomarker of heart failure in patients with cardiomyopathy . The pathophysiology of heart failure in single ventricle ( SV ) circulation may be distinct from that of cardiomyopathies . A distinct pattern of BNP elevation in heart failure in the SV population was hypothesized : it is elevated in heart failure secondary to ventricular dysfunction but not in isolated cavopulmonary failure . BNP was measured prospect ively in SV patients at catheterization ( n = 22 ) and when assessing for heart failure ( n = 11 ) ( 7 normal controls ) . Of 33 SV subjects ( median age 62 months ) , 13 had aortopulmonary connections and 20 had cavopulmonary connections .  Median and mean + /- SD BNP levels by shunt type were 184 and 754 + /- 1,086 pg/ml in the patients with aortopulmonary connections , 38 and 169 + /- 251 pg/ml in the patients with cavopulmonary connections , and 10 and 11 + /- 5 pg/ml in normal controls , respectively ( p = 0.004 ) . Median systemic ventricular end-diastolic pressure ( 8 mm Hg , R = 0.45 ) , mean pulmonary artery pressure ( 14.5 mm Hg , R = 0.62 ) , and mean right atrial pressure ( 6.5 mm Hg , R = 0.54 ) were correlated with plasma BNP . SV subjects with symptomatic heart failure from dysfunctional systemic ventricles had median and mean + /- SD BNP levels of 378 and 714 + /- 912 pg/ml ( n = 18 ) compared with patients with isolated failed Glenn or Fontan connections ( 19 and 23 + /- 16 pg/ml [ n = 7 , p = 0.001 ] ) and those with no heart failure ( 22 and 22 + /- 12 pg/ml [ n = 8 , p = 0.001 ] ) . Excluding the group with cavopulmonary failure , the severity of heart failure from systemic ventricular dysfunction was associated with plasma BNP . In conclusion , plasma BNP is elevated in SV patients with systemic ventricular or left-sided cardiac failure . BNP is not elevated in patients missing a pulmonary ventricle with isolated cavopulmonary failure Background —Impaired cardiac autonomic nervous activities and increased neurohumoral activities ( CANA , NHA ) characterize Fontan patients . However , the clinical significance of these changes is not clearly understood . Our purpose was to clarify the clinical significance of the CANA and NHA in stable Fontan patients . Methods and Results —We divided 22 atriopulmonary connection ( APC ) and 75 total cavopulmonary connection ( TCPC ) patients into 4 subgroups according to New York Heart Association ( NYHA ) class ( 1.8±0.6 ) and measured various CANA and NHA indices . All NHA indices were elevated in the symptomatic patients ( P<0.001 ) . Natriuretic peptides were higher in the APC than in the TCPC patients , and the hemodynamics showed no correlation with brain natriuretic peptide in the APC patients . Low arterial oxygen saturation and impaired hemodynamics greatly influenced all elevated NHA indices ( P<0.01 ) , except for plasma renin activity , in the TCPC patients . Impaired CANA indices did not relate to NYHA class , although surgeries were associated with lower heart rate variability . In addition to poor correlation between NHA and CANA , age and ventricular morphology had no impact on all CANA and NHA indices , except for high norepinephrine in right ventricular Fontan patients . Conclusions —Although symptomatic Fontan patients exhibit higher NHA , CANA is not related to either NYHA class or NHA . APC itself is responsible for higher natriuretic peptides , and arterial oxygen desaturation has a great impact on elevated NHA in the TCPC patients . These characteristics of the NHA and CANA differ from those of heart failure patients with biventricular physiology Background — Children and young adults with single-ventricle physiology have abnormal exercise capacity after the Fontan operation . A medication capable of decreasing pulmonary vascular resistance should allow improved cardiac filling and improved exercise capacity . Methods and Results — This study was a double-blind , placebo-controlled , crossover trial conducted in children and young adults after Fontan . Subjects were r and omized to receive placebo or sildenafil ( 20 mg three times daily ) for 6 weeks . After a 6-week washout , subjects crossed over for an additional 6 weeks . Each subject underwent an exercise stress test at the start and finish of each phase . After taking sildenafil , subjects had a significantly decreased respiratory rate and decreased minute ventilation at peak exercise . At the anaerobic threshold , subjects had significantly decreased ventilatory equivalents of carbon dioxide . There was no change in oxygen consumption during peak exercise , although there was a suggestion of improved oxygen consumption at the anaerobic threshold . Improvement at the anaerobic threshold was limited to the subgroup with single left or mixed ventricular morphology and to the subgroup with baseline serum brain natriuretic peptide levels ≥100 pg/mL. Conclusions — In this cohort , sildenafil significantly improved ventilatory efficiency during peak and submaximal exercise . There was also a suggestion of improved oxygen consumption at the anaerobic threshold in 2 subgroups . These findings suggest that sildenafil may be an important agent for improving exercise performance in children and young adults with single-ventricle physiology after the Fontan operation . Clinical Trial Registration — URL : http:// clinical trials.gov . Unique identifier : NCT00507819 To evaluate the relationship between plasma concentration of amino-terminal fragment of pro-brain natriuretic peptide ( NT-proBNP ) , functional capacity , and right ventricular overload in survivors of tetralogy of Fallot ( TOF ) repair , we prospect ively studied 70 operated TOF patients ( 44 males , 21 ± 1 years old ; mean ± SEM ) who underwent , during the same day , echocardiography , cardiac magnetic resonance imaging , neurohormonal characterization ( plasma NT-proBNP , catecholamines , plasma renin activity , and aldosterone assay ) , and cardiopulmonary exercise testing . Forty-eight age- and sex-matched healthy volunteers served as the control group . Compared to controls , maximal workload and peak oxygen consumption ( VO2/kg ) were lower in operated TOF patients ( p < 0.001 ) , whereas NT-proBNP concentration was elevated ( p < 0.001 ) . No difference was found among the other neurohormones . In operated TOF patients , NT-proBNP showed a significant positive correlation with right ventricular ( RV ) end systolic and end diastolic volumes and RV systolic pressure , and it showed a negative correlation with peak VO2/kg and RV ejection fraction . From multivariable analysis , NT-proBNP concentration was found to be an independent predictor of peak VO2/kg , RV end systolic volume , and RV systolic pressure . These results show an association among RV overload , decrease in functional capacity , and cardiac natriuretic peptide expression in operated TOF patients . NT-proBNP plasma assay may be a useful tool for diagnostic purpose s and for decision making in this setting BACKGROUND The aim of this study was to assess the relation between plasma B-type natriuretic peptide ( BNP ) levels and right ventricular function evaluated by tissue Doppler imaging ( TDI ) in patients after repair of tetralogy of Fallot ( ToF ) . METHODS Twenty-five patients with a mean age of 14.1 + /- 4.4 years who underwent repair of ToF at a mean age of 4.9 + /- 5.1 years enrolled in this study . The control group consisted of 29 healthy children at a mean age of 13.1 + /- 2.8 years . The right ventricle and pulmonary regurgitation ( PR ) were assessed by two-dimensional echocardiography and color Doppler . Blood sample s for BNP levels were taken and TDI was performed at rest . RESULTS Plasma BNP levels were significantly higher in patients than in controls ( 28.3 + /- 24.1 vs. 7.4 + /- 2.3 pg/mL , P = 0.0001 ) . The myocardial performance index ( MPI ) ( 1.08 + /- 0.35 vs. 0.58 + /- 0.11 , P = 0.0001 ) was higher and isovolumic acceleration ( IVA ) ( 3.1 + /- 0.7 vs. 5.4 + /- 1.0 m/s(2 ) , P = 0.0001 ) was lower in patients . The correlations were also significant between the degree of PR and MPI ( r = 0.7 , P = 0.0001 ) and also IVA ( r = -0.7 , P = 0.0001 ) . The correlations were also significant between the BNP level and MPI ( r = 0.6 , P = 0.0001 ) , IVA ( r = -0.4 , P = 0.002 ) and the degree of PR ( r = 0.6 , P = 0.0001 ) . CONCLUSION As a result , plasma BNP level increases in patients with ToF and both MPI and IVA from the right ventricular basal segments might be used to assess the right ventricular function Background — Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction , yet its impact on patients with systemic right ventricles ( RVs ) remains unknown . Methods and Results — A multicenter , r and omized , double-blind , placebo-controlled , crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs . Of 29 patients studied ( age , 30.3±10.9 years ) , 21 had transposition of the great arteries with a Mustard baffle , and 8 had congenitally corrected transposition of the great arteries . Baseline values were as follows : & OV0312;o2max , 29.8±5.6 mL · kg−1 · min−1 ( 73.5±12.9 % predicted value ) ; RV ejection fraction , 41.6±9.3 % ; N-terminal pro brain natriuretic peptide ( NT-proBNP ) , 257.7±243.4 pg/mL ( normal < 125 pg/mL ) ; and angiotensin II , 5.7±4.9 pg/mL ( normal < 5.0 pg/mL ) . Comparing losartan to placebo showed no differences in & OV0312;o2max ( 29.9±5.4 versus 29.4±6.2 mL · kg−1 · min−1 ; P=0.43 ) , exercise duration ( 632.3±123.0 versus 629.9±140.7 seconds ; P=0.76 ) , and NT-proBNP levels ( 201.2±267.8 versus 229.7±291.5 pg/mL ; P=0.10 ) , despite a trend toward increased angiotensin II levels ( 15.2±13.8 versus 8.8±12.5 pg/mL ; P=0.08 ) . Conclusions — In adults with systemic RVs , losartan did not improve exercise capacity or reduce NT-proBNP levels . Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients AIMS Our purpose was to evaluate the effect of a treatment over six months with bisoprolol on the surrogate parameters of N-Terminal-pro brain natriuretic peptide , subsequently to be described as brain natriuretic peptide , peak uptake of oxygen , and ventricular function assessed by magnetic resonance imaging in grown ups and adults who had undergone surgical correction of tetralogy of Fallot . METHODS AND RESULTS We design ed a prospect i ve , r and omized , double-blind , placebo controlled trial . We enrolled 33 patients , aged 30.9 plus or minus 9.5 years in either class 1 or 2 of the grading of the New York Heart Association class with both levels of brain natriuretic peptide greater than 100 pg/ml and a reduced peak uptake of oxygen less than 25 ml/kg/min . During treatment with Bisoprolol , the levels of brain natriuretic peptide increased significantly from 206 plus or minus 95 to 341 plus or minus 250 pg/ml ( p < 0.05 ) , and those of atrial natriuretic peptide from 4117 plus or minus 1837 to 5340 plus or minus 2102 fmol/ml ( p = 0.0005 ) . These measures remained unchanged in the group of patients receiving the placebo .  Peak uptake of oxygen did not differ significantly in either group , nor did treatment have any significant effect on right and left ventricular volumes and ejection fractions as determined by magnetic resonance imaging . The clinical state as judged within the grading system of the 
    Output:
    
In all patients after correction for tetralogy of Fallot , BNP levels were elevated and correlated significantly with right ventricular end-diastolic dimensions and severity of pulmonary valve regurgitation .
Patients with a systemic right ventricle had elevated BNP levels , and positive correlations between BNP and right ventricular function were seen .
In conclusion , this review shows an overall increase in BNP values in complex CHD , although differences between types of congenital heart anomaly are present .