Effect of atrial fibrillation on plasma NT-proBNP in chronic heart failure

Acute Effect of Atrial Fibrillation on Circulating Natriuretic Peptides: The Influence of Heart Rate, Rhythm Irregularity, and Left Atrial Pressure Overload

Plasma natriuretic peptides (NPs) are increased in patients with atrial fibrillation (AF) compared with the patients with sinus rhythm. This study investigated whether this phenomenon is intrinsic to heart rhythm irregularity and independent of the heart rate and left atrial pressure (LAP) overload. We investigated 46 patients (age: 59 ± 10 years, male gender: 77%) with non-valvular paroxysmal AF who were scheduled for catheter ablation and had documented stable sinus rhythm for at least 18 hours before the procedure. All patients underwent direct measurement of right atrial pressure and LAP, simultaneously with assessment of plasma B-type NP, N-terminal pro-brain NP, and mid-regional pro-atrial NP. The baseline measurement was followed by induction of AF by rapid atrial pacing in the first 24 patients and by regular pacing from the coronary sinus at 100/min (corresponding to the mean heart rate during induced AF) in the latter 22 patients. Hemodynamic assessment and blood sampling were repeated after 20 min of the ongoing AF or fast regular paging. The baseline characteristics and hemodynamic measurements were comparable between study groups; however, patients in the regular atrial pacing group had a higher body mass index and a larger left atrial diameter compared with the induced AF group. Plasma levels of all 3 NPs increased significantly during induced AF but not during fast regular pacing, and the increase of NPs was independent of right atrial pressure and LAP. Baseline concentrations of NPs and heart rhythm irregularity were the only independent predictors of increased NPs.

Doppler Mean Gradient Is Discordant to Aortic Valve Calcium Scores in Patients with Atrial Fibrillation Undergoing Transcatheter Aortic Valve Replacement

BACKGROUND

Doppler mean gradient (MG) may underestimate aortic stenosis (AS) severity when obtained during atrial fibrillation (AF) because of lower forward flow compared with sinus rhythm (SR). Whether AS is more advanced at the time of referral for aortic valve intervention in AF compared with SR is unknown. The aim of this study was to examine flow-independent computed tomographic aortic valve calcium scores (AVCS) and their concordance to MG in AF versus SR in patients undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Patients who underwent TAVR from 2016 to 2020 for native valve severe AS with left ventricular ejection fraction ≥ 50% were identified from an institutional TAVR database. MGs during AF and SR in high-gradient AS (HGAS) and low-gradient AS (LGAS) were compared with AVCS (AVCS/MG ratio). AVCS were obtained within 90 days of pre-TAVR echocardiography.

RESULTS

Six hundred thirty-three patients were included; median age was 82 years (interquartile range [IQR], 76-86 years), and 46% were women. AF was present in 109 (17%) and SR in 524 (83%) patients during echocardiography. Aortic valve area index was slightly smaller in AF versus SR (0.43 cm²/m² [IQR, 0.39-0.47 cm²/m²] vs 0.46 cm²/m² [IQR, 0.41-0.51 cm²/m²], P = .0003). Stroke volume index, transaortic flow rate, and MG were lower in AF (P < .0001 for all). AVCS were higher in men with AF compared with SR (3,510 Agatston units [AU] [IQR, 2,803-4,030 AU] vs 2,722 AU [IQR, 2,180-3,467 AU], P < .0001) in HGAS but not in LGAS. AVCS were not different in women with AF versus SR. Overall AVCS/MG ratios were higher in AF versus SR in HGAS and LGAS (P < .03 for all), except in women with LGAS.

CONCLUSIONS

AVCS were higher than expected by MG in AF compared with SR. The very high AVCS in men with AF and HGAS at the time of TAVR suggests late diagnosis of severe AS because of underestimated AS severity during progressive AS and/or late referral to TAVR. Additional studies are needed to examine the extent to which echocardiography may be underestimating AS severity in AF.

Prognostic value of natriuretic peptides in heart failure: systematic review and meta-analysis

Risk models, informing optimal long-term medical management, seldom use natriuretic peptides (NP) in ascertaining the absolute risk of outcomes for HF patients. Individual studies evaluating the prognostic value of NPs in HF patients have reported varying effects, arriving at best estimates requires a systematic review. We systematically summarized the best evidence regarding the prognostic value of brain natriuretic peptide (BNP) and NT-proBNP in predicting mortality and hospitalizations in ambulatory heart failure (HF) patients. We searched bibliographic databases from 2005 to 2018 and included studies evaluating the association of BNP or NT-proBNP with mortality or hospitalization using multivariable Cox proportional hazard models. We pooled hazard ratios using random-effect models, explored heterogeneity using pre-specified subgroup analyses, and evaluated the certainty of evidence using the Grading of Recommendations and Development Evaluation framework. We identified 67 eligible studies reporting on 76,178 ambulatory HF patients with a median BNP of 407 pg/mL (261-574 pg/mL). Moderate to high-quality evidence showed that a 100-pg/mL increase in BNP was associated with a 14% increased hazard of mortality (HR 1.14, 95% CI 1.06-1.22); a 1-log-unit increase was associated with a 51% increased hazard of mortality (HR 1.51, 95% CI 1.41-1.61) and 48% increased hazard of mortality or hospitalization (HR 1.48, 95% CI 1.29-1.69). With moderate to high certainty, we observed a 14% independent relative increase in mortality, translating to a clinically meaningful increase in absolute risk even for low-risk patients. The observed associations may help in developing more accurate risk models that incorporate NPs and accurately prognosticate HF patients.

N-terminal pro brain natriuretic peptide eliminates the prognostic effect of atrial fibrillation in patients with chronic heart failure

AIMS

Co-morbid atrial fibrillation (AF) increases both mortality and N-terminal pro brain natriuretic peptide (NT-proBNP) concentrations in patients with chronic heart failure (CHF). It is unclear whether AF worsens prognosis independently from NT-proBNP concentrations. If AF was an independent risk factor, NT-proBNP levels for outcome prediction would need to be adjusted in patients with AF. We aimed to analyse the influence of AF on the prognostic value of NT-proBNP in patients with CHF.

METHODS AND RESULTS

A total of 2541 consecutive CHF patients with sinus rhythm (SR) or AF were identified in the outpatients' CHF registry of the University of Heidelberg, Germany. Of these, 250 patients with SR were individually matched to 250 patients with AF with respect to NT-proBNP, New York Heart Association functional class, sex, age, and aetiology of CHF. In the general sample, both AF and NT-proBNP were associated with all-cause mortality [hazard ratio (HR) = 1.96, 95% confidence interval (CI) 1.61-2.39, P < 0.001; and HR = 1.03 per 1000 ng/L increase, 95% CI 1.02 to 1.04, P < 0.001, respectively]. After matching, NT-proBNP retained its prognostic power (HR = 1.13 per 1000 ng/L increase, 95% CI 1.10 to 1.16, P < 0.001), but AF did not (HR = 0.91, 95% CI 0.66 to 1.25, P = 0.56). Despite similar prognosis, matched patients with SR were in more advanced CHF than were AF patients as indicated by a lower left ventricular ejection fraction (30 ± 13% vs. 34 ± 14%, P < 0.001).

CONCLUSIONS

The prognostic value of NT-proBNP in CHF is not influenced by concomitant AF. AF, in return, might be a surrogate of a worse cardiac condition rather than an independent risk factor.

NT-proBNP prognostic value is maintained in elderly and very elderly patients with chronic systolic heart failure

BACKGROUND

Circulating concentrations of N-terminal fragment of the prohormone of brain natriuretic peptide (NT-proBNP) are influenced by age and common age-related comorbidities, such as renal dysfunction. Therefore, utility of NT-proBNP for prediction of prognosis in the aged has been questioned. We aimed to investigate the prognostic value of NT-proBNP across age classes in a cohort of patients with chronic systolic HF.

METHODS AND RESULTS

We enrolled 2364 consecutive outpatients with HF and left ventricular ejection fraction ≤50%. Patients were classified according to age quartiles, and a very elderly subgroup was identified, aged ≥85 years. After baseline assessment (including NT-proBNP testing), patients were followed-up for the composite of cardiovascular death, heart transplantation or ventricular assistance device implantation (primary outcome) and for all-cause death (secondary outcome). Patients in the fourth quartile (Q4, age ≥ 77 years, n = 638) and in the very elderly subgroup (age ≥ 85 years, n = 153), had higher NT-proBNP (p < .001 vs Q1). NT-proBNP was independently associated with primary and secondary outcome at 1- and 5-years follow-up in the whole population, as well as in Q4 and in the very elderly subgroup (all p < .05). Compared to the whole population, Q4 and very elderly had higher NT-proBNP cut-off for prediction of 1-year primary (4188 and 9729 ng/l, respectively vs 3710 ng/l) and secondary outcome (4296 and 7634 ng/l, respectively vs 3056 ng/l).

CONCLUSIONS

NT-proBNP predicts mortality in elderly and very elderly patients with chronic systolic HF, both at mid- and long-term follow-up. Higher NT-proBNP prognostic cut-off should be considered in the aged HF population.

Longitudinal evaluation of ventricular ejection fraction and NT-proBNP across heart failure subgroups

OBJECTIVES

Left ventricular ejection fraction (EF) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are important surrogate markers of cardiac function and wall stress. Randomized trials of heart failure (HF) have shown improvements in survival in patients with reduced EF (<40%, HFrEF) but not with preserved EF (≥50%, HFpEF) or mid-range EF (40-49%, HFmrEF). Limited information is available on the trajectory of EF in contemporary heart failure management programs (HFMPs).

DESIGN

201 HF patients consecutively enrolled 2010-2011 in the outpatient-based HFMP of Skåne University Hospital in Lund were included in the study. Probable etiology, EF, NT-proBNP and medications were assessed at baseline and 1 year after enrollment.

RESULTS

HFrEF was the most common heart failure subgroup (78.1% of patients) in this HFMP, followed by HFmrEF (14.9%) and HFpEF (7.0%). The most common etiology was ischemic heart disease (IHD, 40.8%). Complete recovery of EF (>50%) was rare (14.1% of patients with HFrEF and 26.7% with HFmrEF), some degree of improvement was observed in 57.7% and 46.7% of patients. LVEF improved on average 9.1% in patients with HFrEF (p < .001) and NT-proBNP decreased from 4,202 to 2,030 pg/ml (p < .001). A similar trend was noticed for the HFmrEF group but was not statistically significant. The improvement in LVEF was consistent across subgroups with HF attributable to IHD (6.2%), idiopathic dilated cardiomyopathy (7.1%) and tachycardia-induced HF (17.5%).

CONCLUSIONS

This study provides estimates of the improvement in LVEF and NT-proBNP that can be expected with contemporary management across subgroups of HF and different etiologies in a contemporary HFMP.

Comparative accuracy of NT-proBNP and MR-proANP for the diagnosis of acute heart failure in dyspnoeic patients

AIMS

To compare the performance of the natriuretic peptides (NPs) NT-proBNP and MR-proANP for the diagnosis of acute heart failure (AHF) in subsets of conditions potentially confounding the interpretation of NPs.

METHODS AND RESULTS

We studied 312 patients, presenting to the emergency department with new onset of dyspnoea or worsening of chronic dyspnoea within the last 2 weeks. Performance of NPs for the diagnosis of AHF was tested and compared using C-statistics in the entire cohort and in conditions previously described to confound interpretation of NPs such as older age, renal failure, obesity, atrial fibrillation or paced rhythm, and in the NT-proBNP grey zone. AHF was diagnosed in 139 patients. In the entire cohort, the diagnostic performance of NT-proBNP was comparable with that of MR-proANP. Receiver operating characteristic analysis demonstrated that optimal diagnostic cut-offs were higher in the presence of older age, kidney failure or rhythm disorder. However, there were no statistically relevant differences between the receiver operating characteristic curves analysed in the total population and those studied in the pre-specified subsets severe kidney failure, advanced age, obesity, atrial fibrillation and paced rhythm, and grey zone NT-proBNP values. Moreover, the diagnostic performance of NT-proBNP was comparable with that of MR-proANP in the subsets.

CONCLUSIONS

The performance of NT-proBNP and MR-proANP for AHF is comparable in the total population as well as in the subsets with potentially confounding characteristics such as older age, renal dysfunction, obesity, atrial fibrillation and paced rhythm, or those with NT-proBNP values in the grey zone.

Hemodynamic Determinants of the Biologic Variation of N-Terminal Pro-B-Type Natriuretic Peptide in Patients With Stable Systolic Chronic Heart Failure

BACKGROUND CONTEXT

Biologic variation of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) may affect blood levels and risk stratification. The sources of NT-proBNP variation are unknown.

METHODS AND RESULTS

We performed NT-proBNP measurements and clinical and hemodynamic assessments in 50 patients with heart failure with reduced ejection fraction (HFrEF) who met criteria for clinical stability over 2 time intervals. Hemodynamic variables were measured with the use of inert gas rebreathing and impedance cardiography. Heart rhythm was monitored with the use of external electrocardiographic event recorders throughout the study. Determinants of NT-proBNP-levels and both absolute (ΔNT-proBNP_abs) and relative (ΔNT-proBNP_%) changes at 1-week and 2-week intervals were identified with the use of univariable and multivariable linear mixed-effects models and linear regression analyses, respectively. Clinical and hemodynamic variables did not significantly change between study visits. The individual variation of NT-proBNP at 2 weeks was 9.2% (range 3.9%-18.6%). Weight and glomerular filtration rate were independently associated with baseline NT-proBNP concentrations (P = .01 and P = .005, respectively). There was no relationship between absolute and relative changes of NT-proBNP at 1-week intervals and changes in clinical and hemodynamic variables. Absolute change of NT-proBNP at 2-week intervals was associated with absolute change in left cardiac work index (P = .008), and relative change in NT-proBNP at 2-week intervals was determined by relative change of thoracic fluid content index (P = .008) and diastolic blood pressure (P = .01). The coefficients of determination (R²) for the multivariable models with Δ_1wkNT-proBNP_abs, Δ_2-weeksNT-proBNP_abs, Δ_1wkNT-proBNP_%, and Δ_2wksNT-proBNP_% as dependent variables were 0.21, 0.19, 0.10, and 0.32, respectively.

CONCLUSIONS

In patients with stable HFrEF, changes in clinical and hemodynamic variables only marginally contribute to the variation of NT-proBNP.

BNP and NT-proBNP as prognostic markers in persons with chronic stable heart failure

Prognosis permits clinicians to separate persons with heart failure (HF) into subgroups based on likely health outcomes. Treatment is partly guided by these likely outcomes. This systematic review explores whether brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are independent predictors of prognosis in persons with chronic stable HF. We electronically searched Medline, Embase, AMED, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CINAHL for English-language articles published between 1989 and mid-2012. We utilized trained reviewers and standardized forms to screen articles for inclusion and extracted data from included articles. All included studies were summarized in narrative and tabular form. We used the Hayden criteria to assess the risk of bias. Sixteen BNP publications and 88 NT-proBNP publications were included in the systematic review. BNP was positively associated with all-cause and HF mortality. NT-proBNP was positively associated with all-cause and cardiovascular mortality. BNP and NT-proBNP levels are useful for estimating prognosis in persons with chronic stable HF. Further research is required to establish optimal cutpoints and to assess whether prognostic effects differ by age, sex, or time period.

How much atrial fibrillation causes symptoms of heart failure?

INTRODUCTION

Patients with atrial fibrillation (AF) are more symptomatic than patients with sinus rhythm. However, it is unknown what per cent of time spent in AF is associated with symptoms.

METHODS

We used a limited access dataset from the Atrial Fibrillation Follow-up Investigation of Rhythm Management trial. Patients had their current rhythm and New York Heart Association (NYHA) class recorded at baseline and at every follow-up visit. The ratio of number of visits when patients were in AF to the total number of visits was used as a surrogate measure of AF burden. The median number of visits was 12 per patient. We grouped patients labelled as class 0 and I by NYHA as having no symptoms and NYHA II or III as having symptoms. Furthermore, we calculated mortality and the prevalence of symptoms depending on the per cent of visits when they had AF.

RESULTS

Of 4060 patients enrolled in the trial, 74 had no follow-up visits and were excluded; the remaining 3986 patients were analysed. Patients who had no or little AF throughout the study (0-20%) had the lowest prevalence of symptoms. Prevalence of symptoms increased with greater per cent of time spent in AF. Specifically, symptoms became more prevalent when AF burden reached 20-40%. Mortality was similar regardless of proportion of visits when patients were in AF.

CONCLUSIONS

Higher AF burden is associated with higher prevalence of symptoms. The increment became significant when patients were in AF at 20-40% of visits.

Atrial fibrillation impairs the diagnostic performance of cardiac natriuretic peptides in dyspneic patients: results from the BACH Study (Biomarkers in ACute Heart Failure)

OBJECTIVES

The purpose of this study was to assess the impact of atrial fibrillation (AF) on the performance of mid-region amino terminal pro-atrial natriuretic peptide (MR-proANP) in comparison with the B-type peptides (BNP and NT-proBNP) for diagnosis of acute heart failure (HF) in dyspneic patients.

BACKGROUND

The effects of AF on the diagnostic and prognostic performance of MR-proANP in comparison with the B type natriuretic peptides have not been previously reported.

METHODS

A total of 1,445 patients attending the emergency department with acute dyspnea had measurements taken of MR-proANP, BNP, and NT-proBNP values on enrollment to the BACH trial and were grouped according to presence or absence of AF and HF.

RESULTS

AF was present in 242 patients. Plasma concentrations of all three peptides were lowest in those with neither AF nor HF and AF without HF was associated with markedly increased levels (p < 0.00001). HF with or without AF was associated with a significant further increment (p < 0.00001 for all three markers). Areas under receiver operator characteristic curves (AUCs) for discrimination of acute HF were similar and powerful for all peptides without AF (0.893 to 0.912; all p < 0.001) with substantial and similar reductions (0.701 to 0.757) in the presence of AF. All 3 peptides were independently prognostic but there was no interaction between any peptide and AF for prediction of all-cause mortality.

CONCLUSIONS

AF is associated with increased plasma natriuretic peptide (MR-proANP, BNP and NT-proBNP) levels in the absence of HF. The diagnostic performance of all three peptides is impaired by AF. This warrants consideration of adjusted peptide thresholds for diagnostic use in AF and mandates the continued search for markers free of confounding by AF.

N-terminal pro-b-type natriuretic peptide and left atrial function in patients with congestive heart failure and severely reduced ejection fraction

AIMS

Amino-terminal portion of pro-B-type natriuretic peptide (NT-pro-BNP) is a valuable diagnostic and prognostic marker in congestive heart failure (CHF). In CHF patients, elevation of natriuretic peptide levels correlate with decreased left ventricular (LV) ejection fraction (EF) and increased left atrial (LA) volumes, but a correlation with LA function that is a determinant of haemodynamic and clinical status in CHF with independent prognostic value has never been investigated. Aim of this study was to evaluate the relationship between cardiac neurohormonal activation and LA function in patients with CHF due to dilated cardiomyopathy.

METHODS AND RESULTS

One hundred and one patients (86% males; mean age, 64 ± 11 years) with dilated ischaemic or non-ischaemic cardiomyopathy, LV EF ≤45% (mean LV EF, 33 ± 8%), and New York Heart Association class II-IV underwent transthoracic echocardiography to evaluate LA fractional active and total emptying from M- and B-Mode images, and, on the same day, venous blood sample collection to dose NT-pro-BNP. By univariate analyses, NT-pro-BNP significantly correlated to age, LA dimensions, LA function indexes, EF, and functional class. At multivariate analysis, LV EF and M- or B-Mode indexes of LA function were the only independent predictors of NT-pro-BNP values. A NT-pro-BNP cut-off of 1480 pg/mL identified LA dysfunction with 89% specificity and 54% sensitivity.

CONCLUSION

In CHF patients with severely impaired systolic function, NT-pro-BNP levels reflect LA and LV dysfunction. These data should prompt studies to investigate the relationship between changes of LA function and NT-pro-BNP levels and their clinical value as prognostic and therapeutic targets in CHF.

Atrial fibrillation and amino-terminal pro-brain natriuretic peptide as independent predictors of prognosis in systolic heart failure

BACKGROUND

Survival of patients with systolic heart failure (HF) may be influenced by the presence of chronic atrial fibrillation (AF) and circulating concentrations of B-type natriuretic peptides. In this study, we sought to assess the prognostic value of chronic AF in comparison to those of amino-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels and of echocardiographic parameters among HF patients of the entire study population and in those with AF.

METHODS

Plasma NT-proBNP levels and echocardiography were prospectively assessed in 489 patients with chronic systolic HF (LV ejection fraction <or=45%) in sinus rhythm or AF (16%). Follow-up duration was 26+/-15 months.

RESULTS

Patients with AF were older (p<0.0001), had a worse NYHA class (p=0.002) and higher NT-proBNP levels (p<0.0001) than those in sinus rhythm. Presence of AF (HR [hazards ratio]: 2.01, p=0.013) and plasma NT-proBNP (HR: 3.05, p<0.0001) were the only independent predictors of all-cause mortality. At receiver operating characteristic analyses, the threshold level for outcome prediction of NT-proBNP was higher in patients with AF (3883 pg/ml) than in patients in sinus rhythm (1653 pg/ml). Multivariate analysis performed in patients with HF and AF showed that plasma NT-proBNP was the most important predictor of death after statistic adjustment for age.

CONCLUSIONS

Chronic AF and NT-proBNP independently predicted the outcome of patients with HF. The threshold level of NT-proBNP for outcome prediction was different in patients with AF with respect to those in sinus rhythm. NT-proBNP was the most important independent predictor of all-cause mortality in HF patients with AF.

Biomarkers in heart failure management

PURPOSE OF REVIEW

Recent literature on the role of biomarkers in heart failure is reviewed, focusing on B-type natriuretic peptide.

RECENT FINDINGS

Knowledge of the processes which increase ventricular stress, thus increasing B-type natriuretic peptide, is key to appropriate utilization and interpretation of B-type natriuretic peptide levels. B-type natriuretic peptide is a useful adjunct to confirm or rule out heart failure. B-type natriuretic peptide is a robust prognostic indicator in all stages of heart failure, with prognostic significance in patients undergoing cardiac and noncardiac surgery, and in those with acute coronary syndromes. Serial B-type natriuretic peptide testing predicts outcomes in hospitalized patients with heart failure. The role of B-type natriuretic peptide in screening high-risk populations is promising, but its use in unselected populations is unclear. There is increasing evidence that the use of B-type natriuretic peptide to guide heart failure management is associated with improved clinical outcomes and reduced health costs.

SUMMARY

Biomarkers play an important role in heart failure, but there remain unanswered questions regarding optimization of their use. They should be used as an adjunct to, not replacement for, clinical assessment. Currently available B-type natriuretic peptide assays have limitations relating to clinical variability and assay specificity. Other neurohormonal, inflammatory and metabolic markers may add complementary information to that provided by currently available B-type natriuretic peptide assays.

Amino-terminal pro-B-type natriuretic peptide testing for the diagnosis or exclusion of heart failure in patients with acute symptoms

When used for the evaluation of patients with acute symptoms in the emergency department setting, amino-terminal pro-B-type natriuretic peptide (NT-proBNP) testing is highly sensitive and specific for the diagnosis or exclusion of acute destabilized heart failure (HF), with results comparable to those reported for B-type natriuretic peptide (BNP) testing. When used for the diagnostic evaluation of the patient with possible HF, NT-proBNP testing returns information that may be superior to clinical judgment. However, the optimal application of NT-proBNP is in concert with history and physical examination, adjunctive testing, and with the knowledge of the differential diagnosis of an elevated NT-proBNP level. Studies indicate a dual use for NT-proBNP, both to exclude acute HF (where NT-proBNP concentrations <300 ng/L have a 98% negative predictive value), as well as to identify the diagnosis. To identify acute HF in patients with dyspnea, an age-independent NT-proBNP cut point of 900 ng/L has a similar value as that reported for a BNP value of 100 ng/L. However, age stratification of NT-proBNP using cut points of 450, 900, and 1,800 ng/L (for age groups of <50, 50-75, and >75 years) reduces false-negative findings in younger patients, reduces false-positive findings in older patients, and improves the overall positive predictive value of the marker without a change in overall sensitivity or specificity. Clinically validated, cost-effective algorithms for the use of NT-proBNP testing exist. Therefore, the logical use of NT-proBNP for the evaluation of the patient with suspected acute HF is useful, cost-effective, and may reduce adverse outcomes compared with standard clinical evaluation without natriuretic peptide testing.

Amino-terminal pro-B-type natriuretic peptide testing for inpatient monitoring and treatment guidance of acute destabilized heart failure

Although typically elevated at presentation in the context of destabilized heart failure (HF), amino-terminal pro-B-type natriuretic peptide (NT-proBNP) values typically decrease rapidly among patients who have a favorable response to therapy. Given this, it is natural to examine the relation between NT-proBNP and therapeutic interventions for acute HF. Both presentation and posttreatment NT-proBNP concentrations have some value for prognostication of recurrent HF hospitalization or death. However, the percent change in NT-proBNP after treatment for acute HF may be a more powerful method for risk stratification. Although prospective studies on the effect of NT-proBNP measurement in guiding therapy in acute destabilized HF are lacking, observational data suggest that a 30% decrease in NT-proBNP values during hospitalization is a reasonable goal. If a baseline measure of NT-proBNP is not available, an NT-proBNP level <4,000 ng/L after acute treatment is an alternative goal. Because the criteria for determining restabilization from destabilized HF prominently include clinical and routine laboratory testing rather than NP measures, the frequency of NT-proBNP measurement should not be excessive in patients with acute HF, with measures at baseline/presentation and after perceived recompensation to evaluate for the desired decrease in NT-proBNP concentrations. A remeasurement of NT-proBNP may also be useful for evaluation of new or worsened symptoms. In those patients without a decrease in NT-proBNP despite perceived recompensation from HF, a review of adequacy of treatment, goals of therapy, and consideration of prognosis is recommended.

Structural and functional remodeling of the left atrium: clinical and therapeutic implications for atrial fibrillation

Left atrial (LA) structural and functional remodeling reflects a spectrum of pathophysiological changes that have occurred in response to specific stressors. These changes include alterations at the levels of ionic channels, cellular energy balance, neurohormonal expression, inflammatory response, and physiologic adaptations. There is convincing evidence demonstrating an important pathophysiological association between LA remodeling and atrial fibrillation (AF). Measures that will prevent, attenuate, or halt these processes of LA remodeling may have a major public health impact with respect to the epidemic of AF. In this review, we describe the mechanisms involved in LA remodeling and highlight the existing and potential therapeutic options for its reversal, and implications for AF development.