Brain natriuretic peptide kinetics during dynamic exercise in patients with chronic heart failure

Temporal changes in plasma brain natriuretic peptide levels during exercise stress-echocardiography in patients with dilated cardiomyopathy

The aim of this study was to evaluate temporal changes in brain natriuretic petide (BNP) levels during exercise stress-echocardiography in patients with dilated cardiomyopathy with respect to the left ventricular contractile reserve. We studied 55 consecutive patients with dilated cardiomyopathy (mean age, 55 ± 10 years, 49 (89.1%) male). All patients underwent exercise stress-echocardiography on a treadmill using the modified Bruce protocol. Contractile reserve was assessed by measuring changes in the wall motion score index (ΔWMSI) at rest and and at peak exercise. Levels of BNP were measured at rest, in the first minute, and after 20 minutes following termination of the stress test. Thirty-six patients had preserved left ventricular contractile reserve and 19 patients did not. Patients with preserved left ventricular contractile reserve showed a continuous rise in BNP levels from baseline to peak exercise and to 20 minutes following exertion (83.95 ± 108.51 versus 105.89 ± 116.00 versus 110.95 ± 119.70 ng/L, P < 0.001, respectively). On the other hand, patients without preserved left ventricular contractile reserve showed a decline in BNP levels at peak exercise as compared to baseline (335.49 ± 693.11 versus 320.08 ± 562.60 P = 0.031). ΔBNP was positively correlated with preserved contractile reserve (r = 0.46, P = 0.03) and lower NYHA class (r = -0.65, P = 0.001) in patients in whom baseline LVEF was lower than 20%. Multivariate analysis identified only WMSI at rest (beta -3.365, P = 0.008, 95 CI 0.03 to 0.411) as an independent predictor of left ventricular contractile reserve.The increase in BNP levels during exercise stress-echocardiography is associated with preserved left ventricular contractile reserve in patients with dilated cardiomyopathy.

Acute responses to intermittent and continuous exercise in heart failure patients

BACKGROUND

The purpose of this study was to compare cardiopulmonary responses, exercise adherence, tolerance, and safety of optimized high-intensity interval exercise (HIIE) compared with moderate-intensity continuous exercise (MICE) in patients with heart failure and reduced ejection fraction (HFREF).

METHODS

Twenty patients with HFREF (aged 61 ± 9.9 years) were randomly assigned to HIIE corresponding to 2 × 8 minutes of 30-second intervals at 100% of peak power output and 30-second passive recovery intervals and to a 22-minute MICE corresponding to 60% of peak power output. Gas exchange, electrocardiogram, and blood pressure were measured continuously. Cardiac troponin T (cTnT), C-reactive protein (CRP), and brain natriuretic peptide (BNP) were measured before, 20 minutes after, and 24 hours after HIIE and MICE.

RESULTS

Cardiopulmonary responses did not differ between MICE and HIIE. Higher exercise adherence and efficiency were observed on HIIE with a similar perceived exertion and time spent above 90% of peak oxygen consumption compared with MICE. Neither HIIE nor MICE caused any significant arrhythmias or increased CRP, BNP, or cTnT.

CONCLUSIONS

Compared with MICE, HIIE demonstrated a higher exercise adherence and was well tolerated in patients with HFREF, while still providing a high-level physiological stimulus and leaving indices of inflammation (CRP), myocardial dysfunction (BNP), and myocardial necrosis (cTnT) unaffected.

Effects of the recombinant form of the natural human B-type natriuretic peptide and levosimendan on pulmonary hyperventilation and chemosensivity in heart failure

BACKGROUND

The origin of dyspnea in chronic heart failure (HF) is multifactorial, and excessive ventilation is thought to play a role in inducing this symptom. Chemosensivity is augmented in HF, correlates with increased pulmonary ventilation (VE), and is an adverse prognostic marker. Despite increased blood levels of natriuretic peptides in clinical conditions associated with dyspnea, their effect on pulmonary VE and chemoreceptor activity remains unexplored.

METHODS

We tested in a prospective, placebo-controlled, three-way cross-over, double-blind randomized study the effects of the recombinant form of the natural human B-type natriuretic peptide (R-BNP) in comparison with placebo and levosimendan on chemoreflex sensitivity at rest, as well as their effects on pulmonary VE, systemic blood pressure, heart rate and sympathetic serum activity both at rest and during exercise.

RESULTS

Eleven stable chronic HF patients were randomized to sessions of 6-min treadmill-walking tests during placebo, or levosimendan or R-BNP intravenous infusion in the following conditions: room air, hypoxia, and hypercapnia. R-BNP administration determined higher pulmonary ventilatory response at rest and during exercise (P < 0.001) consequent to a boost of respiratory rate (P < 0.001) under room air and hypoxia conditions. Norepinephrine blood levels increased from rest to exercise in all conditions without differences among placebo, levosimendan, and R-BNP effects. BNP blood levels remained unchanged.

CONCLUSIONS

The novelty of the present findings is that R-BNP infusion in HF patients can boost pulmonary ventilatory response at rest and during exercise.

Plasma ANP and BNP during exercise in patients with major depressive disorder and in healthy controls

BACKGROUND

Increased levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have been shown to reduce the hormones in the HPA axis. In this study we addressed the question whether patients with unmedicated major depressive disorder (MDD) might have altered baseline levels of these natriuretic peptides and an altered response to acute exercise.

METHODS

An incremental exercise test was performed in 18 patients with MDD and in 18 healthy controls. Plasma concentrations of ANP and BNP were determined at rest, during the exercise test and 30 min post exercise using immunoradiometric assays.

RESULTS

During the exercise test the concentrations of ANP and BNP increased significantly in both groups. The MDD group showed significantly lower levels of ANP than the controls at rest, at maximal work rate and post exercise and of BNP at rest and at maximal work rate. The dynamic changes of both ANP and BNP, respectively, from baseline to maximal work rate were significantly lower in the MDD group. A slightly lower (non-significant) maximal work rate was observed in the MDD group compared with the controls.

LIMITATIONS

Group sizes are relatively limited.

CONCLUSION

Lower concentrations of ANP and BNP during rest and exercise were observed in the MDD patients together with a decreased dynamic response to maximal exercise. Hypothetically, the reduced ANP and BNP concentration contributes to the high hormone levels in the HPA system seen in depressive disorders. Of interest for future research is whether physical training might increase the levels of ANP and BNP and thereby diminish depressive symptoms.

N-terminal pro-brain natriuretic peptide and exercise capacity in chronic heart failure: data from the Heart Failure and a Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) study

OBJECTIVES

To examine the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and exercise capacity in a large contemporary cohort of patients with chronic heart failure.

BACKGROUND

Natriuretic peptides such as NT-proBNP are important biomarkers in heart failure. The relationship between NT-proBNP and exercise capacity has not been well studied.

METHODS

We analyzed the relationship between baseline NT-proBNP and peak oxygen uptake (peak VO(2)) or distance in the 6-minute walk test in 1383 subjects enrolled in the HF-ACTION study. Linear regression models were used to analyze the relationship between NT-proBNP and peak Vo(2) or distance in the 6-minute walk test in the context of other clinical variables. Receiver operator curve analysis was used to evaluate the ability of NT-proBNP to accurately predict a peak VO(2) <12 mL/kg per minute.

RESULTS

NT-proBNP was the most powerful predictor of peak VO(2) (partial R(2) = 0.13, P < .0001) of 35 candidate variables. Although NT-proBNP was also a predictor of distance in the 6-minute walk test, this relationship was weaker than that for peak VO(2) (partial R(2) = 0.02, P < .0001). For both peak VO(2) and distance in the 6-minute walk test, much of the variability in exercise capacity remained unexplained by the variables tested. Receiver operator curve analysis suggested NT-proBNP had moderate ability to identify patients with peak VO(2) <12 mL/kg per minute (c-index, 0.69).

CONCLUSIONS

In this analysis of baseline data from HF-ACTION, NT-proBNP was the strongest predictor of peak VO(2) and a significant predictor of distance in the 6-minute walk test. Despite these associations, NT-proBNP demonstrated only modest performance in identifying patients with a low peak VO(2) who might be considered for cardiac transplantation. These data suggest that, although hemodynamic factors are important determinants of exercise capacity, much of the variability in exercise performance in heart failure remains unexplained by traditional clinical and demographic variables.

Diastolic function and BNP changes during exercise predict oxygen consumption in chronic heart failure patients

B-type natriuretic peptide (BNP) is a diagnostic and prognostic marker in heart failure (CHF) patients.

AIM

To assess the relation between BNP, diastolic function and exercise capacity in CHF patients.

METHODS

Fifty CHF patients underwent cardiopulmonary exercise testing. BNP levels were determined at baseline and at peak exercise. Patients were divided in two groups: with lower (<14 ml/kg/min) or higher (>or=14 ml/kg/min) peak oxygen consumption (VO(2)).

RESULTS

Seventeen patients with lower peak VO(2) showed larger incidence of restrictive pattern of the transmitral flow (7/17 vs 4/33, p =0.036). E/Ea ratio was inversely related with peak VO(2) (r =-0.419, p =0.004) and directly related with BNP levels at baseline (r =0.449, p =0.001) and at peak exercise (r =0.475, p =0.001). LV ejection fraction was similar in the two groups. Independent predictors of exercise tolerance were E/Ea ratio (p =0.003), lg BNP at baseline (p =0.034) and increase in lg BNP during exercise (p =0.038).

CONCLUSIONS

In CHF patients, E/Ea ratio is a predictor of exercise tolerance and is related with BNP level at rest and at peak exercise.

Usefulness of N-terminal pro-B-type natriuretic peptide increase with exercise for predicting cardiovascular mortality in patients with heart failure

N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) level at rest is related to left ventricular (LV) function and cardiovascular mortality in patients with heart failure (HF). There are limited and controversial data regarding changes in NT-pro-BNP level during exercise in patients with HF. The aim of this study was to investigate the effects of exercise on NT-pro-BNP levels and the relation between increases in NT-pro-BNP and the LV ejection fraction and cardiovascular mortality in patients with HF. Seventy-five patients with HF (New York Heart Association classes I to III) and 20 healthy subjects were enrolled in the study. Echocardiographic examination was performed. The modified Bruce protocol was used for symptom-limited exercise testing. Levels of NT-pro-BNP were measured at rest and after peak exercise. The patients were followed up for 690 to 840 days for cardiovascular mortality. Exercise induced significant increases in NT-pro-BNP in patients and controls. Except for a relative increase in NT-pro-BNP during exercise (relative DeltaNT-pro-BNP), NT-pro-BNP concentrations at rest and during peak exercise and absolute increases in NT-pro-BNP during exercise (absolute DeltaNT-pro-BNP) were significantly higher in patients with HF (p <0.001). Absolute DeltaNT-pro-BNP was positively correlated with NT-pro-BNP at rest (p <0.001). The level of absolute DeltaNT-pro-BNP was the most important parameter in predicting a LV ejection fraction <30% (p <0.001). Absolute DeltaNT-pro-BNP and LV end-systolic volume were found to be independent predictors of mortality (p = 0.012 and p = 0.015, respectively). In conclusion, exercise induced increases in NT-pro-BNP in patients and healthy subjects. Absolute increase in NT-pro-BNP is a reliable parameter in predicting a low LV ejection fraction and may help in the identification of patients at high risk for mortality.

Value of brain natriuretic peptide in the perioperative follow-up of children with valvular disease

OBJECTIVE

To characterize N-terminal pro-brain natriuretic peptide (N-proBNP) and troponin I (TnI) profile following mitral and/or aortic valve surgery and to evaluate correlations with echocardiography measures and outcome criteria.

DESIGN AND SETTING

Prospective cross-controlled study in a university children's hospital.

PATIENTS

Twenty children with acquired valvular disease requiring valvular surgery.

INTERVENTIONS

We prospectively studied clinical, biochemical, and echocardiographic characteristics at baseline and 6, 12, 24 h and 3-4 weeks postoperatively.

RESULTS

TnI peaked 6 h after surgery and remained elevated during the first 24 h. N-proBNP was significantly lower 3-4 weeks after surgery than during the perioperative period. Overall, N-proBNP was correlated with the Pediatric Heart Failure Index, left ventricle shortening fraction, left atrium to aorta ratio, left ventricle mass index, end-systolic wall stress, and with outcome measures such as inotropic score, duration of inotropic support, and ICU length of stay. Preoperative N-proBNP was significantly more elevated in patients with complicated outcome than in patients with uneventful postoperative course.

CONCLUSIONS

In pediatric valvular patients, perioperative N-proBNP is a promising risk stratification predicting factor. It is correlated with evolutive echocardiographic measures, need for inotropic support, and ICU length of stay.

Outpatient monitoring and treatment of chronic heart failure guided by amino-terminal pro-B-type natriuretic peptide measurement

Amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is a strong and independent prognostic marker in patients across the spectrum of heart failure (HF) stages, including patients managed in the outpatient setting. Serial measures of NT-proBNP are more valuable than single measures for prognosis, and biologic variation of the marker should allow serial monitoring. Furthermore, given that NT-proBNP levels decrease in response to the addition of therapies with proven benefit for HF (including angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, diuretics, spironolactone, exercise therapy, and biventricular pacing), it is logical to expect that targeting therapy to decrease NT-proBNP levels may facilitate more optimal use of proven HF therapies and may reduce adverse clinical outcomes. The optimal strategy for NT-proBNP monitoring with regard to frequency of testing or whether to use standard or individualized targets is still being determined. Preliminary results are promising for targeting an outpatient NT-proBNP concentration of approximately < or =1,000 ng/L. Current data suggest that when NT-proBNP levels are not at goal or increase from prior measurements, the risk for hazard is increased. Adjustments in treatment and serial clinical follow-up with NT-proBNP retesting should be considered at frequent intervals until biochemical stabilization or achievement of a maximally tolerated medical program.

Relation of B-type natriuretic peptide levels before and after exercise and functional capacity in patients with idiopathic dilated cardiomyopathy

Although much is known about the value of B-type natriuretic peptide (BNP) at rest, the significance of the responsiveness of BNP during exercise in patients with chronic heart failure (HF) without coronary artery disease remains to be established. A role of BNP release during exercise in the functional disability of patients with chronic HF and idiopathic dilated cardiomyopathy (IDC) was hypothesized. One hundred five consecutive patients with an established diagnosis of HF and IDC who underwent symptom-limited cardiopulmonary exercise testing were studied. BNP was measured immediately before exercise and within 1 minute of the end of exercise. BNP at rest increased significantly at peak exercise (median from 66.5 (first, third quartiles 18, 168) to 72.0 pg/ml (26, 208), p <0.001), but BNP response was not uniform. BNP response increased in 63% of patients, did not change in 22%, and decreased in 15%. BNP at rest and BNP response showed an inverse correlation (p <0.001, r = -0.523). Aging and low left ventricular ejection fraction were independent predictors of higher BNP levels at rest, but lower BNP response. Beta-blocker therapy did not influence BNP response. BNP at rest correlated negatively with functional capacity (p <0.001, r = -0.516), whereas BNP response correlated positively (p = 0.002, r = 0.326). Patients with BNP release (vs patients without) had higher maximum oxygen consumption (19.2 +/- 5.1 vs 15.9 +/- 3.6, p <0.001), better functional capacity (59 +/- 13% vs 50 +/- 15%, p = 0.002), and lower minute ventilation/carbon dioxide production slope (33.6 +/- 4.8 vs 36.5 +/- 7.7, p = 0.026) independent of other clinical parameters. In conclusion, BNP release during exercise could be a determinant of functional capacity in patients with chronic HF and IDC.

Maximum oxygen uptake at peak exercise in elderly patients with coronary artery disease and preserved left ventricular function: the role of inflammation on top of tissue Doppler-derived systolic and diastolic function

BACKGROUND

Several studies have shown that longitudinal systolic function and left ventricular filling pressures, as assessed with tissue Doppler imaging, predict exercise capacity.

AIM

The aim of this study was to evaluate whether natriuretic peptides and inflammatory parameters can independently predict maximum oxygen uptake at peak exercise (VO2max) on top of tissue Doppler imaging-derived markers.

METHODS

We evaluated 142 patients (age 70 +/- 6 years, 77% men) with known or suspected coronary artery disease and a preserved left ventricular ejection fraction (> or = 50%). All patients underwent bicycle spiroergometry, and N-terminal pro-B-type natriuretic peptide levels were determined. Cytokines (IL-6 and soluble tumor necrosis factor receptors 1 and 2) and high-sensitivity C-reactive protein were measured as inflammatory markers. Tissue Doppler imaging was applied to evaluate peak long axis systolic velocities (Sm) and early mitral annulus velocities (E'). Ratio of early transmitral flow (E) to E' was assessed as marker of left ventricular filling. Analysis of variance, comparing VO2max quartiles, was used to determine univariate predictors and linear regression to determine multivariate VO2max predictors.

RESULTS

Average VO2max was 18.5 +/- 5.7 mL/kg per minute (range 6-36.6). Compared with the highest quartile, patients with low VO2max were more frequently women (P < .0001). N-terminal pro-B-type natriuretic peptide and cytokine levels were significantly higher in the lower VO2max categories. Longitudinal myocardial velocities increased, and E/E' decreased along with increasing VO2max. In multivariate linear regression analysis, VO2max was independently predicted by sex, glucose, Sm, E/E', and cytokine levels.

CONCLUSION

Maximum oxygen uptake at peak exercise in patients with known or suspected coronary artery disease and preserved systolic function was independently predicted by inflammatory makers on top of tissue Doppler-derived systolic and diastolic function.

Influence of atrial fibrillation on cardiac brain natriuretic peptide release during haemodynamic stress in heart failure

BACKGROUND

The determinants of release of brain natriuretic peptide (BNP) in heart failure (HF) are incompletely understood, particularly, the effect of heart rhythm and haemodynamic stress.

AIMS

To investigate the effect of haemodynamic stress on cardiac BNP release in HF and differentiate this response for atrial fibrillation (AF) and sinus rhythm (SR).

METHODS

In 18 HF patients (ejection fraction<40%, 9 in AF and 9 in SR) haemodynamics and BNP levels were measured from arterial and coronary sinus samples at baseline, after 10 min of 20 degrees passive head up tilt (HUT) and after 10 min of isometric handgrip (IHG) exercise. From these data, we calculated a transcardiac BNP gradient and compared results between the AF and SR cohort.

RESULTS

During haemodynamic stress in both groups, there were no significance differences in left sided filling pressures. At baseline, there were no differences in BNP measurements between the SR and AF group. The transcardiac BNP gradient increased significantly in the SR (p=0.02) but not the AF cohort, after HUT. During IHG exercise, there was a significant decrease in cardiac BNP release in the AF cohort (p=0.03) but not the SR cohort.

CONCLUSION

These data imply in HF, cardiac rhythm influences cardiac BNP release in response to haemodynamic stress.

Influence of physical exercise and relationship with biochemical variables of NT-pro-brain natriuretic peptide and ischemia modified albumin

BACKGROUND

The diagnostic approach and the clinical management of patients presenting with suspected acute coronary syndrome or cardiac dysfunction are as yet challenging. Although ischemia modified albumin (IMA) and natriuretic peptides were recently proposed for detection of myocardial ischemia and cardiac dysfunction, little information is available on preanalytical and metabolic sources of variability of these markers.

METHODS

To establish the influence of a regular endurance training and the relationship with conventional biochemical variables, NT-pro-brain natriuretic peptide (NT-proBNP) and IMA were assayed, along with cardiac troponin T (cTnT), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine and albumin, in 35 sedentary healthy individuals and 50 male professional road cyclists, 12-24 h following the last demanding training session.

RESULTS

Athletes displayed higher values of both LDH (299+/-61 vs. 257+/-36 U/l, P=0.002) and CK (184+/-123 vs. 115+/-74 U/l, P=0.011), and slightly lower concentrations of creatinine (82+/-12 vs. 87+/-9 micromol/l, P=0.044). No athlete or sedentary control displayed cTnT concentrations exceeding the lower sensitivity limit of the assay. As compared to the sedentary controls, main IMA concentration was increased in athletes (100+/-13 vs. 94+/-6 KU/l, P=0.035), whereas that of NT-proBNP appeared significantly decreased (2.8+/-1.6 vs. 4.3+/-34, P=0.005). The percentage of subjects displaying values exceeding the upper reference limit for the IMA assay was significantly different between athletes and sedentary controls (50% vs. 7%; P<0.001). Pearson correlation analysis revealed an inverse association between IMA and albumin in both athletes (r=-0.640; P<0.001) and sedentary controls (r=-0.583; P=0.001).

CONCLUSIONS

Results of our investigation indicate that a demanding and regular aerobic training regimen, though able to trigger skeletal muscle sufferance, is not associated with any biochemical sign of severe and irreversible chronic cardiac involvement. Moreover, we suggest the adoption of specific IMA diagnostic thresholds following patients' stratification according to serum albumin concentration and physical activity.

The value of cardiopulmonary exercise testing and brain natriuretic peptide plasma levels in predicting the prognosis of patients with chronic heart failure

BACKGROUND

A peak VO2 above 14 ml/min/kg at cardiopulmonary exercise testing and brain natriuretic peptide (BNP) levels is used to estimate survival in patients with chronic heart failure (CHF). Limited data, however, exist comparing the prognostic value of both markers simultaneously in patients with mild to moderate CHF.

METHODS

We prospectively studied 85 consecutive patients (59+/-13 years, 63 men) with CHF (mean LVEF 26+/-6%). All patients underwent cardiopulmonary exercise testing with determination of peak VO2 and measurement of plasma BNP at rest. The incidence of cardiac decompensation and cardiac death was recorded in the follow-up.

RESULTS

During a mean follow-up of 427+/-150 days, four deaths and ten cardiac decompensations occurred. Kaplan-Meier estimates of freedom from clinical events differed significantly for patients above and below the median BNP of 292 pg/ml and also for patients above and below a peak VO2 of 14 ml/min/kg (p<0.05 each). BNP and peak VO2 (area under the ROC 0.75 vs. 0.72) showed a comparable discrimination of CHF patients with adverse cardiac events. The prognostic information of BNP was at least as powerful as that derived from peak VO2. A BNP above 324 pg/ml was associated with a risk ratio of 8.8 for adverse cardiac events.

CONCLUSIONS

In patients with mild to moderate CHF, BNP measurements appear to be an alternative to peak VO2 determined by cardiopulmonary exercise testing for the assessment of prognosis in CHF. BNP may facilitate the ambulatory management of patients with mild to moderate CHF since it is less expensive, less time-consuming, and free of procedural risk compared to exercise testing.

Natriuretic peptide response to dynamic exercise in patients with atrial fibrillation

BACKGROUND

In patients with atrial fibrillation (AF) information regarding exercise release of atrial natriuretic peptide (ANP) is sparse and data on plasma brain natriuretic peptide (BNP) response to exercise is lacking. The aim of this study was to investigate plasma ANP and BNP response to exercise in patients with permanent AF and to assess if the response was different from the response in healthy age- and sex-matched control subjects.

METHODS

Plasma venous concentrations of ANP and BNP were determined at rest, at peak exercise and 30 min from the end of exercise in 38 patients with permanent AF and in 43 age- and sex-matched healthy control subjects.

RESULTS

Plasma concentrations of ANP and BNP were significantly higher in AF patients compared with the healthy control group at rest, peak exercise and after 30 min of recovery (p<0.0001). ANP and BNP increased significantly during exercise in both patients with AF and in the healthy control subjects (p<0.05). The increase in plasma concentration of ANP and BNP during exercise was significantly higher in AF patients compared with healthy controls (p=0.0002 for ANP; p<0.0001 for BNP). In the recovery period plasma BNP decreased significantly (p<0.0001) where as the decrease in plasma ANP was insignificant (p=0.4).

CONCLUSIONS

Patients with permanent AF have elevated levels of ANP and BNP at rest and exhibit much higher exercise release compared to healthy control subjects. This enhanced secretion of potent vasodilating and natriuretic agents may represent an important compensatory mechanism to improve exercise capacity in patients with AF.

Monitoring of patients with heart failure

The recent guidelines of the European Society of Cardiology, recommends laboratory testing as an essential part of the evaluation of the patient presenting with acute or chronic heart failure. The decrease in BNP has been included as a treatment goal for the management of acute heart failure. As for other properties it is important to define what difference can be considered as a real change of the marker in serial measurements. Therefore, knowledge of pathophysiological influences and pre-analytical issues as well as the intraindividual variability of BNP and N-terminal proBNP (NT-proBNP) due to analytical imprecision and biological variation is crucial. Erroneous test results with BNP or NT-proBNP assays are rare but may occasionally occur analytical interferences and should be suspected if the results do not suit the clinical picture or the serial kinetics. Although BNP assays correlate closely, due to lack of standardization no two BNP assays are analytically equivalent, and the same assay must be used for serial measurement. The in-vitro stabilities of BNP and NT-proBNP are sufficient for routine use, and blood sampling for BNP or NT-proBNP directly after arrival without a standardized period of rest is feasible, however, heavy physical exercise should be avoided before blood sampling. To be on the safe side a period of 10 minutes rest before blood sampling is recommended. BNP and NT-proBNP are suitable for heart failure monitoring, and BNP and NT-proBNP changes >50% from baseline correlated well with clinical course and a reduction of mortality in heart failure patients.