Digitalis increases brain natriuretic peptide in patients with severe congestive heart failure

Hydroxychloroquine Mitigates Dilated Cardiomyopathy Phenotype in Transgenic D94A Mice

In this study, we aimed to investigate whether short-term and low-dose treatment with hydroxychloroquine (HCQ), an antimalarial drug, can modulate heart function in a preclinical model of dilated cardiomyopathy (DCM) expressing the D94A mutation in cardiac myosin regulatory light chain (RLC) compared with healthy non-transgenic (NTg) littermates. Increased interest in HCQ came with the COVID-19 pandemic, but the risk of cardiotoxic side effects of HCQ raised concerns, especially in patients with an underlying heart condition, e.g., cardiomyopathy. Effects of HCQ treatment vs. placebo (H₂O), administered in Tg-D94A vs. NTg mice over one month, were studied by echocardiography and muscle contractile mechanics. Global longitudinal strain analysis showed the HCQ-mediated improvement in heart performance in DCM mice. At the molecular level, HCQ promoted the switch from myosin's super-relaxed (SRX) to disordered relaxed (DRX) state in DCM-D94A hearts. This result indicated more myosin cross-bridges exiting a hypocontractile SRX-OFF state and assuming the DRX-ON state, thus potentially enhancing myosin motor function in DCM mice. This bottom-up investigation of the pharmacological use of HCQ at the level of myosin molecules, muscle fibers, and whole hearts provides novel insights into mechanisms by which HCQ therapy mitigates some abnormal phenotypes in DCM-D94A mice and causes no harm in healthy NTg hearts.

Relationship between high-sensitivity cardiac troponin T, B-type natriuretic peptide, and physical function in patients with heart failure

AIMS

High-sensitivity cardiac troponin T (hs-cTnT) and B-type natriuretic peptide (BNP) are associated with prognosis and severity in patients with heart failure (HF); however, their association with physical function is unclear. This study aimed to investigate whether hs-cTnT and BNP levels are associated with physical function in patients with HF.

METHODS AND RESULTS

Hs-cTnT, BNP, and physical function (maximal quadriceps isometric strength [QIS], usual gait speed, and 6-min walk distance [6MWD]) were evaluated in 363 consecutive patients with HF (median age, 70 [60-78] years). Patients were divided into four groups according to their median hs-cTnT and BNP levels. After adjusting for demographic characteristics, laboratory levels, and HF severity, higher hs-cTnT and BNP levels were significantly associated with lower physical function (log hs-cTnT, β = -0.162, P = 0.001, for maximal QIS; β = -0.175, P = 0.002, for usual gait speed, and β = -0.129, P = 0.004, for 6MWD; log BNP, β = -0.090, P = 0.092, for maximal QIS, β = 0.038, P = 0.516, for usual gait speed, and β = -0.108, P = 0.023, for 6MWD). In addition, the high hs-cTnT and high BNP group had significantly lower physical function (all P < 0.05) than the low hs-cTnT and low BNP group.

CONCLUSIONS

Higher hs-cTnT and BNP levels are both associated with lower physical function in patients with HF, but hs-cTnT levels showed a more consistent association. The combination of hs-cTnT and BNP may be effective for the stratification of physical function in patients with HF.

SOMAscan-based proteomic measurements of plasma brain natriuretic peptide are decreased in mild cognitive impairment and in Alzheimer's dementia patients

Alzheimer's disease represents the most common age-related neurodegenerative disorder and a leading cause of progressive cognitive impairment. Predicting cognitive decline is challenging but would be invaluable in an increasingly aging population which also experiences a rising cardiovascular risk. In order to examine whether plasma measurements of one of the established biomarkers of heart failure, brain natriuretic peptide (BNP), reflect a decline in cognitive function, associated with Alzheimer's disease neurodegeneration, BNP levels were analysed, by using a novel assay called a SOMAscan, in 1. cognitively healthy, control subjects; 2. subjects with mild cognitive impairment, and 3. subjects with Alzheimer's disease. The results of our study show that the levels of the BNP were significantly different between the three types of diagnoses (p < 0.05), whereby subjects with mild cognitive impairment had the lowest mean BNP value, and healthy subjects had the highest BNP value. Importantly, our results show that the levels of the BNP are influenced by the presence of at least one APOE4 allele in the healthy (p < 0.05) and in the Alzheimer's disease groups of subjects (p < 0.1). As the levels of the BNP appear to be independent of the APOE4 genotype in subjects with mild cognitive impairment, the results of our study support inclusion of measurements of plasma levels of the BNP in the list of the core Alzheimer's disease biomarkers for identification of the mild cognitive impairment group of patients. In addition, the results of our study warrant further investigations into molecular links between Alzheimer's disease-type cognitive decline and cardiovascular disorders.

B-Type Natriuretic Peptide Modulates Pulmonary Vein Arrhythmogenesis: A Novel Potential Contributor to the Genesis of Atrial Tachyarrhythmia in Heart Failure

BACKGROUND

Heart failure (HF) plays a critical role in the genesis of atrial fibrillation (AF). A high B-type natriuretic peptide (BNP) level occurs in patients with HF and in patients with AF. However, the role of BNP in the pathophysiology of AF is not clear. The purposes of this study were to evaluate the effects of BNP on pulmonary vein (PV) arrhythmogenesis.

METHODS AND RESULTS

Whole-cell patch clamp and fluorescence were used to study the action potential, ionic currents, and calcium homeostasis in isolated single rabbit PV cardiomyocytes before and after a BNP infusion, with or without ODQ (10 μM), milrinone (50 μM), or ouabain (1 μM). BNP increased PV spontaneous activity by 28.2 ± 7.5% at 100 nM and by 23.8 ± 9.1% at 300 nM. Similar to those with BNP, milrinone 50 μM increased the PV beating rate from 3.0 ± 0.2 to 3.6 ± 0.3 Hz (P < 0.0005, n = 7). In the presence of ODQ application, BNP didn't change PV spontaneous activity. BNP (100 nM) increased calcium transients (F/F₀ from 1.6 ± 0.1 to 1.9 ± 0.2, n = 20, P < 0.05) and increased the pacemaker current (0.4 ± 0.1 to 1.0 ± 0.2 pA/pF, n = 17, P < 0.0005) in PV cardiomyocytes. Moreover, BNP (100 nM) increased the transient inward current, sodium currents, sodium-calcium exchanger currents, and L-type calcium current; but reduced late sodium currents and the Na-K pump in PV cardiomyocytes.

CONCLUSION

BNP increases PV arrhythmogenesis, which may contribute to the genesis of atrial tachyarrhythmogenesis in HF. Cyclic GMP activation, phosphodiesterase 3 inhibition and Na⁺ /K⁺ -ATPase inhibition might participate in the BNP modulation of PV electrophysiology.

Natriuretic hormones in brain function

Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain. In this review, the established information on the biosynthesis, release and function of NH is discussed, with particular focus on their role in brain function. The available literature on the expression patterns of each of the NH and their receptors in the brain is summarized, followed by the evidence for their roles in modulating brain function. Although numerous open questions exist regarding this issue, the available data support the notion that NH participate in the central regulation of BP, neuroprotection, satiety, and various psychiatric conditions, including anxiety, addiction, and depressive disorders. In addition, the interactions between the different NH in the periphery and the brain are discussed.

Prognostic Value of NT-proBNP at Rest and Peak Exercise in Patients With Impaired Left Ventricular Function

We aimed to identify whether N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) at peak exercise can provide incremental clinical information over resting levels. A total of 90 patients with systolic heart failure were prospectively studied. Levels of plasma NT-proBNP were assessed at rest and at peak exercise during a cardiopulmonary exercise test. Patients were followed-up for 30 ± 10 months. Levels of NT-proBNP at baseline and peak exercise were significantly correlated with left ventricular ejection fraction ([LVEF] r = −.629, P < .001 and r = −.630, P < .001, respectively) and peak oxygen uptake ([Vo2] r = −.752, P < .001 and r = −.740, P < .001, respectively). Levels of plasma NT-proBNP at peak exercise demonstrated similar predictive ability for the detection of patients with low peak Vo2 and LVEF <28%. Levels of plasma NT-proBNP can detect low-functional class patients and patients who may be the candidates for heart transplantation with high sensitivity and specificity. At baseline and peak exercise, NT–proBNP demonstrates similar prognostic and predictive ability.

Endothelin-1 as a predictor of atrial fibrillation recurrence after pulmonary vein isolation

BACKGROUND

A considerable rate of atrial fibrillation (AF) recurrence is one of the major limitations of pulmonary vein isolation (PVI). Although endothelin-1 (ET-1) is involved in atrial remodeling, it is unknown whether plasma ET-1 level before PVI can be used as a predictive factor for AF recurrence.

OBJECTIVE

The goal of this study was to clarify whether the plasma ET-1 level, before PVI, can be used as a predictive factor for AF recurrence after PVI.

METHODS

Fifty-one patients without structural heart disease who underwent PVI for symptomatic and drug-refractory paroxysmal/persistent AF were included in the study. Neurohumoral factors were measured, and transthoracic echocardiography was performed before and 6 months after each PVI. Mean left atrial (LA) pressure and arterial blood pressure (BP) were evaluated just before PVI. AF recurrence was detected by 12-lead electrocardiogram (ECG), Holter ECG, and event ECG monitor recordings, 3 to 6 months after PVI.

RESULTS

Among plasma levels of ET-1, atrial and brain natriuretic peptides, renin, angiotensin II, and aldosterone before PVI, only ET-1 was significantly higher in the recurrence group compared with the nonrecurrence group (2.15 +/- 0.51 vs. 1.65 +/- 0.35 pg/ml, P < .001). Both mean LA pressure and diastolic BP in the recurrence group were significantly higher than in the nonrecurrence group (mean LA pressure, 10 +/- 3 vs. 8 +/- 3 mm Hg, P < .01; diastolic BP, 82 +/- 11 vs. 71 +/- 12 mm Hg, P < .01). The plasma ET-1 level and mean LA pressure were correlative. Multiple logistic regression analyses showed that higher levels of plasma ET-1 and diastolic BP were significant prognostic predictors of AF recurrence 3 to 6 months after PVI (P < .01 and P < .05, respectively).

CONCLUSION

Our findings suggest that the plasma ET-1 level before PVI could be a crucial predictor of AF recurrence 3 to 6 months after PVI.

Can we use B-type natriuretic peptides to monitor patients with heart failure?

The B-type natriuretic peptides (BNPs) now have a well-established role in the diagnosis of heart failure. There is also a wealth of evidence on their ability as prognostic markers in patients with heart failure. The other potential role of BNPs is in the arena of therapy monitoring, although much less is known regarding this putative application. This review summarizes what evidence there is both for and against using BNPs to monitor heart failure patients.

Cost effectiveness of the B type natriuretic peptide, electrocardiography, and portable echocardiography for the assessment of patients from the community with suspected heart failure

To analyze the cost efficiency of guidelines proposed by the European Society of Cardiology for investigation of patients in the community with suspected heart failure (HF). The guidelines recommend electrocardiography (ECG) and/or measurement of N-terminal pro B type natriuretic peptide (NTproBNP) prior to referral for echocardiography. Portable echocardiography is a new but validated technique for the evaluation of HF. Accordingly, 137 suspected HF patients (mean age 71+/-13 years) from the community underwent ECG and NTproBNP estimation prior to portable echocardiography. Cost effective analysis for ECG, NTproBNP, portable echocardiography and a combination of these; to define valvular heart disease, right ventricular dysfunction and left ventricular systolic and diastolic dysfunction were compared. The cost of abnormal NTproBNP followed by portable echocardiography, abnormal ECG followed by portable echocardiography and portable echocardiography alone for the detection per case of left ventricular systolic dysfunction were 313 euro, 310 euro, and 296 euro respectively and that for detection per case of any of the aforementioned cardiac abnormalities were 198 euro, 223 euro, and 170 euro respectively. Portable echocardiography alone for the assessment of suspected HF patients resulted in a cost reduction of up to 1083 euro for the detection per case of cardiac abnormality. While a strategy where initial NTproBNP estimation is cost effective in detecting any causes of heart failure, portable echocardiography remains the most costeffective strategy to assess patients from the community with suspected heart failure.

N-Terminal Prohormone Brain Natriuretic Peptide as a Marker for Detecting Low Functional Class Patients and Candidates for Cardiac Transplantation: Linear Correlation With Exercise Tolerance

BACKGROUND

N-terminal prohormone brain natriuretic peptide (NT Pro BNP) plasma levels have been associated with indices of left ventricular (LV) function and aerobic capacity in heart failure. The aim of our study was to use NT Pro BNP for the prediction of low functional class patients and also to detect candidates for cardiac transplantation.

METHODS

We studied 100 patients with impaired left ventricular (LV) function. Mean LV ejection fraction (LVEF) was 35% +/- 9%. Blood samples for NT Pro BNP assessment were taken at baseline during treadmill exercise testing. LV cavity diameters, left atrial size, and LVEF were measured by echocardiography.

RESULTS

Plasma levels of NT Pro BNP correlated significantly with peak oxygen consumption (VO(2)) values (r = -0.77, p < 0.001). LVEF correlated well with NT Pro BNP (r = -0.67, p < 0.001). NT Pro BNP plasma levels correlated strongly with New York Heart Association functional class (r = 0.70, p < 0.001). NT Pro BNP values exceeding 335 pg/ml showed 83% sensitivity and 76% specificity for detecting VO(2) values below 20 ml/kg/min (area under the curve [AUC] = 86%, p < 0.001). NT Pro BNP plasma levels exceeding 1,190 pg/ml showed 83% sensitivity and 86% specificity for detecting VO(2) of less than 14 ml/kg/min (AUC = 90%, p < 0.001). NT Pro BNP plasma levels exceeding 1,610 pg/ml showed 87% sensitivity and specificity 82% for detecting VO(2) of less than 10 ml/kg/min (AUC = 90%, p < 0.001). NT Pro BNP plasma levels exceeding 680 pg/ml showed 91% sensitivity and 73% specificity for detecting LVEF of less than 28% (AUC = 86%, p < 0.001).

CONCLUSIONS

NT Pro BNP plasma levels correlate both with LVEF and aerobic capacity, can predict low functional cardiopulmonary exercise capacity in patients with impaired left ventricular function, and are useful for detecting candidates for cardiac transplantation.

Unexplained week-to-week variation in BNP and NT-proBNP is low in chronic heart failure patients during steady state

BACKGROUND

The usefulness of brain-natriuretic-peptide (BNP) and N-terminal-pro-brain-natriuretic-peptide (NT-proBNP) for monitoring of chronic heart failure (CHF) patients has been questioned because of high levels of unexplained variation.

AIMS

Week-to-week total variance (CV(T)), unexplained variation (CV(I)), reference change values (RCV), index of individualities (IOI) and number of samples (N) with week-to-week intervals needed to estimate the underlying homeostatic set point (+/-15%) for BNP and NT-proBNP were calculated in pre-specified stable CHF patients.

METHODS AND RESULTS

We measured plasma concentrations of BNP and NT-proBNP, clinical and laboratory variables in 20 CHF patients with a 7-days interval. Only patients considered to be in steady state were included. The CV(I) was 15% (BNP) and 8% (NT-proBNP). CV(T) was 16% (BNP) and 8% (NT-proBNP) and RCV was 43% (BNP) and 23% (NT-proBNP). IOI was 0.14 for BNP and 0.03 for NT-proBNP and N was 1 for BNP and 1 for NT-proBNP.

CONCLUSIONS

Our data demonstrate that unexplained variation of BNP and NT-proBNP is low in CHF patients during steady state, which is a prerequisite for the use of these peptides for monitoring of the disease.

The effects of medications on circulating levels of cardiac natriuretic peptides

Circulating cardiac natriuretic peptide levels are being used increasingly in a range of clinical circumstances. Since it is evident that drugs used in the treatment of cardiovascular disorders can modulate natriuretic peptide levels, we here review the literature documenting these effects. Diuretics, blockers of the renin-angiotensin system, vasodilator agents, dopamine-like agonists, amiodarone, and perhaps allopurinol and statins suppress natriuretic peptide levels, most obviously in heart failure. Beta-blockers stimulate natriuretic peptide concentrations in hypertensive subjects, whereas in heart failure they have little effect or are stimulatory in the short term and inhibitory with sustained therapy. Digitalis compounds and aspirin tend to increase natriuretic peptide levels, and calcium channel blocking agents have varying effects depending on the individual drug and duration of administration. The effects of other drugs are less clear. Additional information is needed regarding the effects of medications along with dissection of the role of altered cardiac secretion versus changes in plasma clearance as explanation for drug-induced perturbations in natriuretic peptide concentrations. In the meantime, clinicians need to consider the known effects of medications when interpreting plasma levels of the cardiac natriuretic peptides.

Abnormal rhythmic oscillations of atrial natriuretic peptide and brain natriuretic peptide in chronic renal failure

Secretion of ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide) is pulsatile in healthy humans. However, the patterns of secretion of ANP and BNP have not been studied in chronic renal failure. The aim of the present study was to test the hypotheses that ANP and BNP are secreted in pulses in dialysis patients, and that pulsatile secretion is regulated by prostaglandins. Blood samples were drawn every 2 min through an intravenously inserted plastic needle over a period of 1-2 h in 13 dialysis patients and 13 healthy control subjects (Study 1), and in 15 healthy control subjects, who participated in a randomized placebo-controlled cross-over study after treatment with indomethacin and placebo (Study 2). Plasma concentrations of ANP and BNP were determined by RIAs, and the results were analysed for pulsatile behaviour by Fourier transformation. The results from Study 1 showed that the secretion of ANP and BNP was pulsatile in nine patients with chronic renal failure. The maximum amplitude was significantly higher in chronic renal failure compared with control subjects for both ANP and BNP (ANP, 4.3 compared with 0.7 pmol/l; BNP, 2.0 compared with 0.3 pmol/l; values are medians) and correlated positively with the mean plasma level of ANP (rho=0.900, P=0.001; n=9) and BNP (rho=0.983, P=0.000; n=9). The frequency was the same for patients and controls. The results from Study 2 demonstrated pulsatile secretion in all subjects, but both the amplitude and frequency were unaffected by indomethacin. The maximum amplitude correlated positively with the mean plasma level of ANP and BNP during both placebo and indomethacin treatment. It can be concluded that the secretion of ANP and BNP is pulsatile with abnormally high amplitude in chronic renal failure, that prostaglandins apparently are not involved in the secretion of these peptides in healthy subjects and that the high secretion rate in chronic renal failure results in higher ANP and BNP in plasma.

[Brain natriuretic peptide in primary care: diagnostic value in heart failure]

OBJECTIVE

To determine the validity and usefulness of brain natriuretic peptide (BNP) for diagnosing left ventricular dysfunction (LVD).

DESIGN

Prospective, descriptive, multi-centred study to validate the diagnostic test.

SETTING

Primary care centres in the Community of Madrid, Spain.

PARTICIPANTS

Consecutive sample of patients at high risk of presenting with LVD.

INTERVENTIONS

Data will be gathered from anamnesis, physical examination, ECG, and chest x-ray to find the risk factor(s) for LVD and the presence or absence of symptoms of congestive heart failure according to the Framingham scale. BNP will be determined at PC clinics in all patients who meet the inclusion criteria, using the "triage BNP test." All patients included in the study will be referred to an echocardiography service for an echocardiogram, which will be the gold standard test. Two independent cardiologists will evaluate the echocardiograph without knowing the BNP values.

MAIN MEASUREMENTS

BNP concentrations will be compared against the kind and degree of LVD. ROC curves analysis will test the capacity of BNP to diagnose LVD. Optimal sensitivity and specificity value will be calculated by means of the position on the curve resulting from the minimum distance at the cut-off point for best sensitivity and specificity. Then, sensitivity, specificity, and positive and negative predictive values will be calculated.

DISCUSSION

BNP can complement the information provided by other diagnostic tests. It should be included as an important factor in the taking of clinical-therapeutic decisions.

The safety of digoxin as a pharmacological treatment of atrial fibrillation

Digoxin has traditionally been the drug of choice for ventricular rate control in patients with chronic atrial fibrillation (AF), with or without heart failure (HF) with systolic dysfunction. In patients with permanent AF, digoxin monotherapy is ineffective to control ventricular rate during exercise, but the combination of digoxin with a beta-blocker or a non-dihydropyridine calcium channel antagonist can control heart rate both at rest and during exercise. Only a few randomised, controlled studies have evaluated the adverse effects of digoxin in patients with AF in a systematic way and side effects requiring drug withdrawal have rarely been reported. When reported, the most frequent adverse effects were cardiac arrhythmias (ventricular arrhythmias, AV block of varying degrees and sinus pauses). This evidence suggested that, in contrast to other antiarrhythmic drugs, digoxin is a safe drug in patients with AF. However, this safety profile can be erroneous due to the short follow-up of the studies and patient selection. Because patients with HF have been excluded in most studies, the safety profile of digoxin in this population has not been directly addressed. Early recognition that an arrhythmia is related to digoxin intoxication as well as recognition of concomitant medications or medical conditions that may directly alter the pharmacokinetic profile of digoxin, or indirectly alter its cardiac effects by pharmacodynamic interactions remain essential for safe and effective use of digoxin in patients with AF.

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.

Brain natriuretic peptide and optimal management of heart failure

Aside from the important role of brain natriuretic peptide (BNP) in diagnosis, and differential diagnosis of heart failure, this biological peptide has proved to be an independent surrogate marker of rehospitalization and death of the fatal disease. Several randomized clinical trials demonstrated that drugs such as beta blocker, angiotensin converting enzyme inhibitor, spironolactone and amiodarone have beneficial effects in decreasing circulating BNP level during the management of chronic heart failure. The optimization of clinical decision-making appeals for a representative surrogate marker for heart failure prognosis. The serial point-of-care assessments of BNP concentration provide a therapeutic goal of clinical multi-therapy and an objective guidance for optimal treatment of heart failure. Nevertheless new questions and problems in this area remain to be clarified. On the basis of current research advances, this article gives an overview of BNP peptide and its property and role in the management of heart failure.

Independent and incremental prognostic value of endogenous ouabain in idiopathic dilated cardiomyopathy

Increased circulating levels of endogenous ouabain (EO) have been observed in some heart failure patients, but their long term clinical significance is unknown. This study investigated the prognostic value of EO for worsening heart failure among 140 optimally treated patients (age 50+/-14 years; 104 male; NYHA class 1.9+/-0.7) with idiopathic dilated cardiomyopathy. Plasma EO was determined by RIA and by liquid chromatography mass spectrometry, values were linearly correlated (r = 0.89) in regression analysis. During follow-up (13+/-5 months), heart failure progression was defined as worsening clinical condition leading to one or more of the following: sustained increase in conventional therapies, hospitalization, cardiac transplant, or death. NYHA functional class, age, LVEF, peak VO2 and plasma levels of EO were predictive for heart failure progression. Heart failure worsened 1.5 fold (HR: 1.005; 95% CI: 1.001-1.007; p<0.01) for each 100 pmol/L increase in plasma EO. Moreover, those patients with higher plasma EO values had an odds ratio of 5.417 (95% CI: 2.044-14.355; p<0.001) for heart failure progression. Following multivariate analysis, LVEF, NYHA class and plasma EO remained significantly linked with clinical events. This study provides the first evidence that circulating EO is a novel, independent and incremental marker that predicts the progression of heart failure.

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

BACKGROUND

The kinetics of brain natriuretic peptide (BNP) secretion in chronic heart failure (CHF) during dynamic exercise have been the subject of controversial debate. The present study was therefore aimed to further clarify whether marked changes in BNP levels occur during and directly after vigorous exercise in CHF patients.

METHODS

We prospectively studied 37 patients with CHF (60+/-10 years, LVEF 26+/-6%) and 20 healthy controls (58+/-11 years, LVEF 60+/-3%). Standardized exercise testing was performed in all CHF patients and controls. Venous blood samples for measurement of BNP were obtained prior to symptom-limited exercise, at peak exercise and at 1 and 5 min of recovery time.

RESULTS

BNP concentrations were significantly higher in CHF compared to controls at rest, peak exercise and at 1 and 5 min of recovery. BNP levels did not change significantly during exercise in the control group. In CHF patients, BNP levels showed no marked difference at rest (428+/-421 pg/ml), peak exercise (507+/-450 pg/ml, n.s.), 1 min (560+/-460 pg/ml, n.s.) and 5 min recovery (526+/-424 pg/ml, n.s.). Strikingly, 6 of 37 CHF patients (16%) showed a decrease in BNP at exercise compared to rest but none of the controls.

CONCLUSIONS

BNP levels in CHF patients and healthy controls are not significantly altered by vigorous exercise. In contrast to controls, 16% of CHF patients showed a decrease in BNP levels at exercise. In CHF, BNP levels were inversely correlated with peak VO(2), VO(2)-AT and LVEF.

QRS prolongation on surface ECG and brain natriuretic peptide as indicators of left ventricular systolic dysfunction

OBJECTIVE

To determine whether the combination of prolonged QRS duration and brain natriuretic peptide (BNP) levels predicts left ventricular systolic dysfunction (LVSD) with a higher accuracy compared with QRS duration or BNP alone.

SETTING

University hospital.

METHODS

We studied 128 consecutive patients with suspected cardiac disease. At rest the QRS duration on 12-lead ECG and BNP levels were determined. A left ventricular ejection fraction (LVEF) <50% at echocardiography was defined as LVSD.

RESULTS

QRS duration in the LVSD group (n = 66, LVEF 30 +/- 8%) was longer than in the group without LVSD (n = 62, LVEF 60 +/- 5%; QRS 129 +/- 34 vs. 96 +/- 20 ms, P < 0.001). BNP was higher in the LVSD group compared with controls (467 +/- 397 vs. 169 +/- 242 pg mL(-1), P < 0.001). A QRS duration of >0.1, >0.11 or >0.12 s was highly specific (63, 90 and 98%) but less sensitive (84, 81 and 75%) for the prediction of LVSD. A QRS cut-off value of 106 ms was moderately sensitive (65%) but very specific (87%) for the prediction of LVSD, whereas a BNP cut-off value of >84 pg mL(-1) was highly sensitive (89%) but only modestly specific (58%). The positive likelihood ratio for LVSD of abnormal BNP (2.0) and QRS prolongation >0.1 s (2.3) was improved by the combination of both criteria (5.1). In multivariate analysis, BNP and QRS duration were independent predictors of LVSD.

CONCLUSIONS

The combination of abnormal BNP and QRS prolongation yields a higher positive likelihood ratio for the detection of LVSD compared with the two criteria alone.

Brain Natriuretic Peptide in the Management of Heart Failure

Brain natriuretic peptide (BNP), also called B-type natriuretic peptide, is a member of a family of structurally related hormones, the natriuretic peptides. Current data suggest that measurement of BNP plasma concentrations is a useful tool in the diagnosis of acute heart failure in patients presenting to an emergency department with acute dyspnea. Furthermore, BNP constitutes a promising new marker of prognosis after an acute coronary syndrome episode and in patients with chronic heart failure. Nesiritide, the human recombinant form of BNP, is a new vasodilator used in the treatment of acute heart failure that has several potential advantages over current drug therapy.

The use of brain natriuretic peptide as a screening test for left ventricular systolic dysfunction- cost-effectiveness in relation to open access echocardiography

BACKGROUND

Heart failure due to left ventricular systolic dysfunction (LVSD) has a high prevalence in the adult population but is difficult to diagnose accurately on clinical grounds in the community. Early diagnosis is important as effective treatments are available to reduce morbidity and mortality. Echocardiography is widely used to assess heart failure; however, this technology is relatively expensive and of limited availability. A potential diagnostic aid in primary care is the measurement of plasma brain natriuretic peptide (BNP).

OBJECTIVE

This study was performed to assess the value of BNP measurement as a selective pre-screen for breathless patients referred for open access echocardiography.

METHODS

BNP was measured by radioimmunoassay with prior extraction in 83 breathless subjects (age range 37-87 years, mean 72). Standard echocardiography was performed and left ventricular systolic function was assessed.

RESULTS

The prevalence of LVSD was 31% in this group. At cut-off values chosen to give negative predictive values for LVSD of >98% (BNP = 19 pg/ml), the sensitivity, specificity and positive predictive value for BNP were 100, 49.1 and 46.9%. Using this BNP threshold as a pre-screen for echocardiography would make a net saving of pound 964.20 without compromising the diagnostic accuracy.

CONCLUSION

BNP measurement appears to have a significant cost-effective benefit for the selection of patients for echocardiography.

brain natriuretic peptide levels predict functional capacity in patients with chronic heart failure

OBJECTIVES

The goal of this study was to determine if brain natriuretic peptide (BNP) levels are associated with exercise capacity in patients with chronic heart failure (HF).

BACKGROUND

Plasma levels of BNP are increased subject to the degree of systolic and diastolic left ventricular dysfunction in patients with chronic HF. Exercise testing is useful to assess functional capacity and prognosis in chronic HF.

METHODS

We prospectively studied 70 consecutive patients with chronic HF (60.3 +/- 10.4 years, 51 men) referred for cardiopulmonary exercise testing. Resting BNP was obtained after 10 min of supine rest before symptom-limited bicycle exercise testing.

RESULTS

In patients with chronic HF, BNP levels correlated with oxygen uptake (VO(2)), both at anaerobic threshold (VO(2)AT: r = -0.54, p < 0.001) and peak exercise (peak VO(2): r = -0.56, p < 0.001). Impairment of ventilatory efficiency (EqCO(2): r = 0.43, p < 0.001) and maximum exercise level (W % predicted: r = -0.44, p < 0.05) correlated less well with BNP. There was a significant inverse correlation between left ventricular ejection fraction and BNP (r = -0.50, p < 0.05). Brain natriuretic peptide discriminated well chronic HF patients with a peak VO(2) <10 ml/min/kg (area under the receiver operating characteristic [ROC] 0.93) or <14 ml/min/kg (area under the ROC 0.72). A BNP >316 pg/ml was associated with a risk ratio of 6.8 (95% confidence interval, 2.3 to 19.8) for a reduced exercise capacity with a peak VO(2) <14 ml/min/kg.

CONCLUSIONS

Brain natriuretic peptide is clearly associated with exercise capacity in chronic HF. Brain natriuretic peptide levels show a significant correlation with the impairment of VO(2) at peak exercise and anaerobic threshold. Brain natriuretic peptide is able to differentiate between chronic HF patients with moderately and severely impaired exercise capacity.

Marinobufagenin, an endogenous ligand of alpha-1 sodium pump, is a marker of congestive heart failure severity

BACKGROUND

A reduced cardiac output in chronic heart failure (CHF) evokes renal NaCl and water retention, and, therefore, activates mechanisms promoting natriuresis. Atrial natriuretic peptide (ANP) is one such factor. We hypothesized that another NaCl sensitive endogenous natriuretic factor, i.e., marinobufagenin (MBG), a specific ligand of the alpha-1 subunit of Na/K ATPase (the main kidney isoform) and also a vasoconstrictor and cardiotonic substance, would be elevated in CHF patients in a graded manner with the severity of CHF.

METHODS AND RESULTS

We measured the plasma levels of MBG, alpha-hANP, ouabain-like compound (OLC) and left ventricular (LV) volumes and ejection fraction in 23 consecutive hypertensive male patients with CHF. Plasma MBG levels exhibited progressive increases (0.59 +/- 0.15, 1.08 +/- 0.20, 1.35 +/- 0.17 and 1.88 +/- 0.05 nmol/l NYHA 1-4, respectively) and paralleled the changes of alpha-hANP. Conversely, plasma OLC did not exhibit such increases. Plasma MBG correlated with alpha-hANP (r = 0.82; P < 0.0001). Both MBG and alpha-hANP correlated with LV systolic (r = 0.55 and r = 0.47; P < 0.01) diameter and inversely with ejection fraction (r = -0.73 and r = -0.60; P < 0.01). OLC did not exhibit correlations with alpha-hANP or LV volumes, but positively correlated with systolic brachial blood pressure and with pulse pressure.

CONCLUSIONS

In CHF, MBG exhibits progressive increases similar to ANP, varies with CHF severity and correlates with LV systolic function. We hypothesize, that, in CHF, the concurrent production of these two natriuretic hormones, a vasorelaxant, ANP, and a vasoconstrictor, MBG, potentiate each other's natriuretic effects, but may offset their vasoactive actions.

Endogenous cardiac glycosides, a new class of steroid hormones

The search for endogenous digitalis has led to the isolation of ouabain as well as several additional cardiotonic steroids of the cardenolide and bufadienolide type from blood, adrenals, and hypothalamus. The concentration of endogenous ouabain is elevated in blood upon increased Na(+) uptake, hypoxia, and physical exercise. Changes in blood levels of ouabain upon physical exercise occur rapidly. Adrenal cortical cells in tissue culture release ouabain upon addition of angiotensin II and epinephrine, and it is thought that ouabain is released from adrenal cortex in vivo. Ouabain levels in blood are elevated in 50% of Caucasians with low-renin hypertension. Infusion over several weeks of low concentrations of ouabain, but not of digoxin, induces hypertension in rats. A digoxin-like compound, which has been isolated from human urine and adrenals, as well various other endogenous cardiac glycosides may counterbalance their actions within a regulatory framework of water and salt metabolism. Marinobufagenin, for instance, whose concentration is increased after cardiac infarction, may show natriuretic properties because it inhibits the alpha1 isoform of Na(+)/K(+)-ATPase, the main sodium pump isoform of the kidney, much better than other sodium pump isoforms. In analogy to other steroid hormones, cardiotonic steroid hormones in blood are bound to a specific cardiac glycoside binding globulin. The discovery of ouabain as a new adrenal hormone affecting Na(+) metabolism and the development of the new ouabain antagonist PST 2238 allows for new possibilities for the therapy of hypertension and congestive heart failure. This will lead in turn to a better understanding of the disease on a physiological and endocrinological level and of the action of ouabain on the cellular level as a signal that is transduced to the plasma membrane as well as to the cell nucleus.

[Brain natriuretic peptide. Diagnostic value in heart failure]

BACKGROUND

Nowadays a number of diverse biochemical markers have been identified in patients with heart failure (HF) that could indicate the severity of the patients' illness. Among them, probably the most useful is brain natriuretic peptide (BNP) because it is easily obtained and because of its diagnostic and prognostic information. Our objective was to assess the association between BNP and other different associated variables previously known to be related to the evolution of HF, as well as its utility to distinguish systolic from diastolic HF.

PATIENTS AND METHOD

We studied 114 patients admitted consecutively for symptomatic HF for all causes (age: 66 years, male: 60%). In all patients plasma BNP was measured, from the third day of admission, with a specific radioinmunoassay. Echocardiography was performed in 101 patients.

RESULTS

BNP plasma levels increased in proportion to functional class (p = 0.01) and the degree of left ventricular dysfunction (p = 0.0001, r = 0.44). There was also an association between BNP and male sex (p = 0.008), higher plasmatic creatinine (p = 0.01, r = 0.25), Iarger ventricular diameters (p = 0.0001) and higher pulmonary systolic pressure (p = 0.001, r = 0.44). In the multivariate analysis, BNP was independently related to the rest of variables with left systolic ventricular function (p = 0.0001). Despite this association, we did not find a satisfactory cut-off value in BNP, with a good sensitivity and specificity value from the total number of patients, of which specifically systolic dysfunction as a cause of HF was detected.

CONCLUSIONS

a) BNP increases proportionately to the left ventricular dysfunction and HF severity, and b) BNP is not a useful tool to distinguish systolic from diastolic HF.

Digoxin

After 200 years of use, digitalis still appears to have a place in our armamentarium for heart failure and atrial fibrillation despite the proven survival benefits with ACE inhibitors and beta-blockers. Digoxin therapy is inexpensive and well tolerated and may result in considerable savings. Digoxin is the only oral inotrope that does not increase mortality in heart failure patients, particularly if low doses are being used. Digoxin therapy should be used in patients with systolic heart failure who continue to have signs and symptoms despite therapeutic doses of ACE inhibitors or diuretics or in patients with atrial fibrillation with or without heart failure for rate control.

Hemodynamic and plasma atrial natriuretic peptide responses to acute digitalis therapy in patients with normal and impaired left ventricular function

BACKGROUND

Digitalis has a long history in the treatment of heart failure but its effects on cardiac hemodynamics and neurohormonal modulation are not well characterized.

AIMS

The purpose of this study was to evaluate the relationship between atrial natriuretic peptide (ANP) and the hemodynamic responses to acute digitalis administration in patients with normal and impaired left ventricular function (LVD).

METHODS AND RESULTS

Thirty patients were enrolled in the study, 20 with LVD (LVEF=22+/-8%) and 10 control subjects (LVEF=77+/-10%). Hemodynamics and plasma ANP concentrations were measured supine and with leg elevation before and after digitalis. In patients with normal ventricular function, the hemodynamic stress of leg elevation in the pre-digitalis state resulted in significant (P<0.05) increases in PAWP and MPAP. Digitalis administration in the supine position produced reductions in heart rate, PAWP, MPAP and CI; SVR was increased. In LVD patients leg elevation further increased PAWP, RAP and MPAP. Digitalis in the supine position, however, reduced RAP, MPAP and PAWP and increased CI. These improved hemodynamics were preserved during the stress of leg elevation. Leg elevation following digitalis resulted in increased ANP concentrations despite decreased cardiac filling pressures.

CONCLUSIONS

Acute digitalis administration results in hemodynamic improvement in LVD patients which may in part result from digitalis stimulated release of myocardial ANP under conditions of hemodynamic stress.

Brain natriuretic peptide-guided therapy for heart failure

The drug treatment of heart failure, once simple, has become complex. Apart from a loop diuretic and digoxin, most patients should now be receiving an angiotensin-converting enzyme inhibitor (or angiotensin II receptor blocker), a beta-blocker and spironolactone. Newer drugs, such as endothelin-receptor antagonists and combined blockers of converting-enzyme and neutral endopeptidase, might soon become available. When to introduce these drugs and what dose is optimal for any individual, are questions that currently vex clinicians. We proposed that plasma levels of the cardiac hormone brain natriuretic peptide (BNP, or better, its 1-76 amino-acid N-terminal fragment, N-BNP), would provide an objective index for guiding drug treatment in patients with established, stable cardiac failure. In a pilot study, 69 patients were randomized to drug treatment based on clinical criteria, or based on plasma levels of N-BNP. After a median follow-up of 9.6 months, those in the N-BNP group had fewer clinical end-points than those in the group managed by clinical criteria alone (19 vs 54; P= 0.02). These preliminary data encourage the concept that the increasingly complex pharmacotherapy for heart failure, both chronic (as in this trial) and acute, might best be guided by an objective measure such as plasma levels of BNP or N-BNP.

Augmented response in plasma brain natriuretic peptide to dynamic exercise in patients with left ventricular dysfunction and congestive heart failure

OBJECTIVES

We have previously demonstrated that patients with symptomatic congestive heart failure (CHF), but not with asymptomatic left ventricular dysfunction (LVD), have augmented plasma atrial natriuretic peptide (ANP) response to exercise. Plasma brain natriuretic peptide (BNP) response to exercise is less extensively studied. The aim of this study was to determine whether responses of plasma BNP during exercise normalized for exercise workload are altered in patients with LVD and CHF.

SUBJECTS AND METHODS

Twenty-nine patients with LVD, 32 patients with CHF (NYHA classes II-III) and 27 age-matched control subjects were studied. Ventilatory, plasma ANP and BNP responses were assessed during symptom-limited cardiopulmonary exercise testing. Plasma natriuretic peptide levels were measured at rest and immediately after peak exercise. The increment in plasma BNP was divided by the increment in oxygen uptake (VO2) from rest to peak exercise, and this ratio [BNP exercise ratio: (peak BNP - rest BNP)/(peak VO2 - rest VO2)] was compared amongst the three groups.

RESULTS

Peak VO2 (Control, LVD and CHF: 28.2 +/- 1.7, 21.1 +/- 1.8, 16.2 +/- 0.6 ml, min(-1) kg(-1), respectively), anaerobic threshold and peak workload became smaller as heart failure worsened. Resting and peak plasma ANP levels were significantly higher only in CHF, whilst resting and peak plasma BNP levels displayed a significant and continuous increase from normal subjects to LVD and CHF. The ANP exercise ratio (1.25 +/- 0.36, 2.61 +/- 0.57, 7.72 +/- 1.65, ANOVA P = 0.0002) was significantly higher only in patients with CHF, whilst the BNP exercise ratio (0.35 +/- 0.10, 2.60 +/- 0.69, 4.98 +/- 0.97, ANOVA P = 0.0001) was significantly higher in patients with LVD and became progressively higher in patients with CHF.

CONCLUSIONS

These data showed that the BNP exercise ratio, an exercise plasma BNP response normalized with exercise workload, was augmented in patients with LVD, and became progressively higher in CHF, suggesting that an augmented exercise BNP ratio exists early in the course of developing CHF.

Cardiac glycosides in the next millennium

Despite the documented efficacy of cardiac glycosides in improving symptoms in patients with heart failure caused by systolic ventricular dysfunction, considerable debate continues as to whether the use of this class of drugs should continue into the next millennium. In this review, the authors briefly examine the basic pharmacology of these drugs relevant to the treatment of heart failure, emphasizing their role in reducing sympathetic nervous system activity in patients with advanced heart failure. Next, withdrawal trials and the Digoxin Investigation Group dataset are reviewed in some detail. Despite these important additional data on the safety and efficacy of digitalis use in heart failure that became available in the 1990s, considerable controversy remains. Perhaps most importantly, if the mechanism by which these drugs improve symptoms in patients with heart failure is principally mediated by sympatholytic activity, do they remain relevant as beta-adrenergic antagonists become standard therapy for this disease?

Cohort study of plasma natriuretic peptides for identifying left ventricular systolic dysfunction in primary care

OBJECTIVES

To determine whether blood natriuretic peptide concentrations are helpful in identifying or excluding left ventricular systolic dysfunction in stable survivors of acute myocardial infarction.

DESIGN

Comparison of blood natriuretic peptide concentrations with echocardiographic assessment of left ventricular systolic function in a general practice population.

SETTING

Practices in Western District of Glasgow audit group.

SUBJECTS

134 long term survivors of myocardial infarction recalled for echocardiography as part of a primary care secondary prevention audit.

MAIN OUTCOME MEASURES

Area under the receiver operating curve for brain natriuretic peptide and N-terminal atrial natriuretic peptide.

RESULTS

Brain natriuretic peptide was of some diagnostic utility in identifying the minority of subjects with severe left ventricular dysfunction (area under curve=0.73) but was unable to discriminate between patients with moderately severe dysfunction and those with preserved left ventricular function (area under curve for moderate or severe dysfunction=0.54). The corresponding values for N-terminal atrial natriuretic peptide for severe and moderate or severe dysfunction were 0.55 and 0.56 respectively.

CONCLUSIONS

Blood natriuretic peptide concentrations are not useful in identifying important left ventricular systolic dysfunction in stable survivors of myocardial infarction.