Discordant Regulation of CRP and NT-proBNP Plasma Levels After Electrical Cardioversion of Persistent Atrial Fibrillation

NT Pro-BNP can be used as a risk predictor of clinical atrial fibrillation with or without left atrial enlargement

Background

NT Pro‐BNP is a blood marker secreted by cardiomyocytes. Myocardial stretch is the main factor to stimulate NT Pro‐BNP secretion in cardiomyocytes. NT Pro‐BNP is an important risk factor for cardiac dysfunction, stroke, and pulmonary embolism. So does atrial myocyte stretching occur when patients have atrial fibrillation (AF)? Whether atrial muscle stretch induced by AF leads to increased NT Pro‐BNP remains unclear. The purpose of this study is to investigate the relationship between NT Pro‐BNP and AF.

Hypothesis

AF can cause changes in myocardial tension. Changes in myocardial tension may lead to increased secretion of NT Pro‐BNP. We hypothesize that NT Pro‐BNP may increase in AF with or without LAD enlargement.

Methods

This clinical study is an observational study and has been approved by the Ethics Committee of the First Affiliated Hospital of Xi'an Jiaotong University. Ethical approval documents is attached. The study retrospectively reviewed 1345 patients with and without AF. After excluding 102 patients who were not eligible, the final total sample size was 1243 cases: AF group 679 patients (378, 55.7% males) and non‐AF group 564 patients (287, 50.8% males). NT Pro‐BNP was observed in AF group and non‐AF group with or without LAD. After adjusting for age, gender, BMI, left atrial diameter, hypertension, diabetes, coronary heart disease, and cerebral infarction, NT Pro‐BNP remains statistically significant with AF.

Conclusion

NT Pro‐BNP can be used as a risk predictor of AF with or without left atrial enlargement.

Biomarkers in Atrial Fibrillation and Heart Failure

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice and an important contributor to cardiovascular morbidity and mortality. Although the exact mechanisms behind AF are not completely elucidated, the underlying pathophysiological changes have been well described. Predisposal factors for AF include the older age, the increased left atrial size, the decreased left atrial function, the presence of heart failure and left ventricular systolic dysfunction and the presence of coronary heart disease or pulmonary or mitral valve disease. In addition to these factors, emerging evidence demonstrate that myocardial strain, fibrosis and inflammation, are associated with AF as well as the pathogenesis of the arrhythmia. The natruretic peptide system including Atrial Natriuretic Peptide (ANP), Brain Natriuretic Peptide (BNP) and C-type Natriuretic Peptide (CNP) is indicative of the level of myocardial strain which may predispose to AF. As a result, the aforementioned peptides are increased in AF patients. The levels of myocardial fibrosis biomarkers, such as ST2 and Galectin-3, are elevated suggesting atrial structural abnormalities, while the increased levels of CRP and Interleukin-6 supplement the inflammatory profile of AF patients. Emerging data for the aforementioned biomarkers are discussed in the present review.

Relationship between Brain Natriuretic Peptide and Recurrence of Atrial Fibrillation after Successful Electrical Cardioversion: an Updated Meta-Analysis

Objective

To investigate the relationship between brain natriuretic peptide and recurrence of atrial fibrillation after successful electrical cardioversion.

Methods

Medline and Embase databases were used to identify publications evaluating BNP/N-Terminal (NT)-proBNP levels in association with atrial fibrillation recurrence after successful electrical cardioversion. Nineteen studies that fulfilled the specified criteria of our analysis were found.

Results

Baseline BNP/NT-proBNP levels of the atrial fibrillation recurrence group were significantly higher than those of the sinus rhythm maintaining group (SMD -0.70, CI [-0.82, -0.58]).

Conclusion

Our analysis suggests that low BNP/NT-proBNP levels are associated with sinus rhythm maintenance, and baseline BNP/NT-proBNP concentrations may be a predictor of atrial fibrillation recurrence after successful electrical cardioversion.

The change in NT-pro-BNP and post-PTMC echocardiography parameters in patients with mitral stenosis. A pilot study

BACKGROUND

The change in the level of NT-pro-BNP (N-terminal-pro-Brain Natriuretic Peptide) is now considered as a reflection of the hemodynamic alterations and its circulatory reductions reported early after successful PTMC (percutaneous transvenous mitral commissurotomy). The present study aims to assess the change in the level of NT-pro BNP following PTMC in patients with mitral stenosis and also to determine the association between circulatory NT-pro-BNP reduction and post-PTMC echocardiography parameters.

METHODS

Twenty five symptomatic consecutive patients with severe MS undergoing elective PTMC were prospectively enrolled. All patients underwent echocardiography before and also 24 to 48 hours after PTMC. Peripheral blood samples were taken for measurement of NT-pro-BNP before as well as 24 to 48 hours after PTMC. The patients were also classified in group with normal sinus rhythm or having atrial fibrillation (AF) based on their 12-lead electrocardiogram.

RESULTS

It was shown a significant decrease in the parameters of PPG (Peak Pressure Gradient), MPG (Mean Pressure Gradient), PHT (Pressure Half Time), PAP (Pulmonary Arterial Pressure), LAV (Left Atrial Volume), and also a significant increase in MVA (Mitral Valve Area) RVS (Right Ventricular S velocity), and strains of lateral, septal, inferior and anterior walls of LA following PTMC. The mean LVEF remained unchanged after PTMC. The mean NT-pro-BNP before PTMC was 309.20 ± 17.97 pg/lit that significantly diminished after PTMC to 235.72 ± 22.46 pg/lit (p = 0.009). Among all echocardiography parameters, only MPG was positively associated with the change in NT-pro-BNP after PTMC. Comparing the change in echocardiography indices between the patients with normal rhythm and those with AF, lower change in PAP was shown in the group with AF. However, more change in the level of NT-pro-BNP after PTMC was shown in the patients with AF compared to those without this arrhythmia.

CONCLUSION

PTMC procedure leads to reduce the level of NT-pro-BNP. The change in NT-pro-BNP is an indicator for change in MS severity indicated by decreasing MPG parameter. Lower change in PAP as well as higher change in NT-pro-BNP is predicted following PTMC in the group with AF compared to those with normal sinus rhythm.

Relationship between brain natriuretic peptides and recurrence of atrial fibrillation after successful direct current cardioversion: a meta-analysis

BACKGROUND

Atrial fibrillation (AF) recurrence is common after successful direct current cardioversion (DCCV), with a 40% rate of recurrence within the first month. Several studies have investigated the potential association between brain natriuretic peptide (BNP) or N-terminal (NT)-proBNP levels before DCCV and the risk of AF recurrence, but results have been inconsistent. We, therefore, conducted a systematic review and meta-analysis of all available data to determine whether sinus rhythm (SR) maintenance after successful DCCV may be determined by preprocedural BNP and NT-proBNP levels.

METHODS

We systematically searched Scopus, the Cochrane library, EMBASE, and MEDLINE databases to identify publications evaluating BNP or NT-proBNP levels in relation to post-DCCV AF recurrence, indexed from inception to September 2013. Among the initial 1,067 citations, 18 studies fulfilled the specified criteria. The difference in BNP and NT-proBNP concentrations in the AF recurrence and the SR-maintaining group was estimated by the standardized mean difference and the estimates of the pooled outcomes were evaluated using random-effects models.

RESULTS

Baseline BNP levels in the AF recurrence group were significantly higher compared to BNP levels in the SR-maintaining group (standardized mean difference [SMD] -1.51, confidence interval [CI] [-2.53, -0.48], P = 0.004). Similar results were observed for NT-proBNP levels, which were significantly higher in the AF recurrence group compared with the SR-maintaining group (SMD -0.63, CI [-1.13, -0.14], P = 0.01).

CONCLUSIONS

Our analysis suggests that low preprocedural BNP/NT-proBNP levels are associated with SR maintenance. The use of BNP or NT-proBNP for prediction of long-term response to DCCV appears to be useful and should be further evaluated.

Value of high-sensitivity C-reactive protein assays in predicting atrial fibrillation recurrence: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis of studies on high-sensitivity C-reactive protein (hs-CRP) assays to see whether these tests are predictive of atrial fibrillation (AF) recurrence after cardioversion.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EMBASE and Cochrane databases as well as a hand search of the reference lists in the retrieved articles from inception to December 2013.

STUDY ELIGIBILITY CRITERIA

This review selected observational studies in which the measurements of serum CRP were used to predict AF recurrence. An hs-CRP assay was defined as any CRP test capable of measuring serum CRP to below 0.6 mg/dL.

PRIMARY AND SECONDARY OUTCOME MEASURES

We summarised test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic curves and bivariate random effects models. Meta-regression analysis was performed to explore the source of heterogeneity.

RESULTS

We included nine qualifying studies comprising a total of 347 patients with AF recurrence and 335 controls. A CRP level higher than the optimal cut-off point was an independent predictor of AF recurrence after cardioversion (summary adjusted OR: 3.33; 95% CI 2.10 to 5.28). The estimated pooled sensitivity and specificity for hs-CRP was 71.0% (95% CI 63% to 78%) and 72.0% (61% to 81%), respectively. Most studies used a CRP cut-off point of 1.9 mg/L to predict long-term AF recurrence (77% sensitivity, 65% specificity), and 3 mg/L to predict short-term AF recurrence (73% sensitivity, 71% specificity).

CONCLUSIONS

hs-CRP assays are moderately accurate in predicting AF recurrence after successful cardioversion.

Natriuretic Peptides as Predictors of Atrial Fibrillation Recurrences Following Electrical Cardioversion

Electrical cardioversion (ECV) can be effective in restoring sinus rhythm (SR) in the majority of patients with atrial fibrillation (AF). Several factors that predispose to AF recurrences, such as age, AF duration and left atrial size have been used to guide a decision for cardioversion, but increasing evidence suggests that they may be rather poor markers of left atrial structural remodeling that determines the long-term success of a rhythm control strategy. In this context, the use of easily obtainable biomarkers, such as the levels of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), to predict AF recurrences may be preferable. Since ANP production is associated with the extent of functional atrial myocardium, and both ANP and BNP reflect atrial pressure and mechanical stretching, these peptides are good candidate biomarkers to assess predisposition to AF recurrences. In this review we focus on the pathophysiological mechanisms and the available clinical evidence regarding the prediction of AF recurrences following successful ECV from pre-procedural ANP and BNP levels.

Adverse effects of permanent atrial fibrillation on heart failure in patients with preserved left ventricular function and chronic right apical pacing for complete heart block

BACKGROUND

The impact of atrial fibrillation (AF) on heart failure (HF) was evaluated in patients with preserved left ventricular (LV) function and long-term right ventricular (RV) pacing for complete heart block.

METHODS

Clinical, echocardiographic, and laboratory parameters of HF were assessed in 35 patients with established AF who had undergone ablation of the atrioventricular node and pacemaker implantation (Group A) and 31 patients who received dual-chamber pacing for spontaneous complete heart block (Group B).

RESULTS

During a follow-up period of 12.7 ± 7.5 years, New York Heart Association (NYHA) functional class increased from 1.3 ± 0.5 to 2.1 ± 0.6 (p < 0.0001) in Group A, and from 1.3 ± 0.4 to 1.6 ± 0.7 (p < 0.01) in Group B. Left ventricular ejection fraction (LVEF) decreased from 59.7 ± 5.1 to 53.0 ± 8.2 (p < 0.0001) in Group A, but remained stable (58.6 ± 4.2 vs. 56.9 ± 7.0 %, p = 0,21) in Group B. At the end of follow-up, markers of LV function were moderately depressed in Group A compared with those in Group B: NYHA class 2.1 ± 0.6 versus 1.6 ± 0.7, p = 0.001; LVEF 53.0 ± 8.2 versus 56.9 ± 7.0 %, p < 0.05; LV diastolic diameter 53.6 ± 5.8 mm versus 50.7 ± 4.9 mm, p < 0.05; N-terminal pro-brain natriuretic peptide (NT-proBNP) 1116.8 ± 883.9 versus 622.9 ± 1059.4 pg/ml, p < 0.05. Progression of paroxysmal AF to permanent AF during follow-up was common, while new onset of AF was rare. Permanent AF was an independent predictor of declining LVEF >10 %, increasing NYHA class ≥1, and NT-proBNP levels >1,000 pg/ml.

CONCLUSIONS

Permanent AF was associated with adverse effects on LV function and symptoms of HF in patients with long-term RV pacing for complete heart block, and appears to play an important role in the development of HF in this specific patient cohort.

Relationship between brain natriuretic peptide and recurrence of atrial fibrillation after successful electrical cardioversion: a meta-analysis

A meta-analysis was undertaken to examine the relationship between plasma brain natriuretic peptide (BNP) levels and recurrence of atrial fibrillation (AF) after successful electrical cardioversion. The literature search was conducted using key inclusion criteria for papers published between January 1980 and March 2011 listed in the PubMed(®)/MEDLINE(®)

DATABASE

Data were analysed using RevMan version 5.1 software; a manual search was also performed. Ten studies were finally included. Results showed that baseline BNP levels were higher in patients with AF recurrence than in those without recurrence, the standardized mean difference in plasma BNP level being -1.35 (95% confidence interval -2.17, -0.53, Z-score for overall effect 3.22). These results suggest that higher plasma BNP levels are associated with a greater risk of AF recurrence. BNP levels may predict AF recurrence after successful electrical cardioversion.

C-reactive protein, interleukin 6, and N-terminal pro-brain natriuretic peptide following cardioversion of atrial fibrillation: is there a role of biomarkers in arrhythmia recurrence?

AIMS

We investigated the role of high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6), and N-terminal pro-brain natriuretic peptide (NTpro-BNP), in atrial fibrillation (AF) recurrence rate.

METHODS

A total of 80 patients with first AF episode were studied prospectively. Echocardiography (ECG), Holter ECG, and measurements of hsCRP, IL-6, and NTproBNP were performed immediately post conversion and at 1 month.

RESULTS

Recurrence was positively related to left atrial volume (P < .001), with no difference in NTpro-BNP, hsCRP, and IL-6. Decreased NTpro-BNP was observed in all at 1 month (P < .001, F = 63.4) and was positively related to left atrial volume (P < .01). In the lone AF subgroup, NTpro-BNP was lower and dropped significantly at 1 month (interaction F = 6.53, P < .01).

CONCLUSIONS

Atrial volume was related to AF recurrence, whereas hsCRP, IL-6, and NTpro-BNP were not reliable for AF relapse. Relation of NTpro-BNP to left atrial volume could indicate a role in the atrial remodeling process.

Factors associated with the development of atrial fibrillation in patients with rheumatic mitral stenosis

The aim of this study was to evaluate the factors associated with the development of atrial fibrillation (AF) in patients with rheumatic mitral stenosis (MS). A total of 146 consecutive patients with rheumatic MS were screened. They were accepted to be in AF group and sinus rhythm group according to their rhythm in the baseline ECG. After screening, 38 patients were excluded due to hyperthyroidism (n = 13), chronic obstructive pulmonary disease (n = 22), malignancy (n = 2) and rheumatoid arthritis (n = 1). Therefore, remaining 108 patients, 74 of whom in sinus rhythm (MS-SR) and 34 of whom in AF (MS-AF) constituted study population. Fourty age- and gender-matched patients constituted control group. Factors associated with development of AF in multivariable analysis included High sensitivity C reactive protein (P = 0.005; odds ratio, 3.44; 95% confidence interval, 1.44-8.22), N-terminal of brain natriuretic peptide precursor (P < 0.0001; odds ratio, 1.03; 95% confidence interval, 1.02-1.06) and left atrial diameter (P < 0.0001; odds ratio, 1.68; 95% confidence interval, 1.32-2.14). Present study suggests that High sensitivity C reactive protein, N-terminal of brain natriuretic peptide precursor and left atrial diameter are associated with development AF in patients with MS.

Long-term prognostic value of baseline C-reactive protein in predicting recurrence of atrial fibrillation after electrical cardioversion

BACKGROUND

An increasing body of evidence links atrial fibrillation (AF) to the inflammatory state. It has been suggested that increased C-reactive protein (CRP) levels are associated with greater risk of AF recurrence at short- and mid-term.

OBJECTIVE

We sought to investigate the association between CRP and long-term risk of AF recurrence.

METHODS

This was a prospective observational study. We investigated the association between baseline CRP levels and recurrence of AF over a 3-year follow-up period after successful electrical cardioversion (EC). A total of 60 patients were studied (mean age: 68.4 +/- 7.2 years, 60% men). All patients were receiving amiodarone for sinus rhythm maintenance. We further divided the study population into three tertiles according to the values of baseline CRP (tertile 1: <0.43 mg/dL; tertile 2: 0.43-0.8 mg/dL; tertile 3: >0.8 mg/dL).

RESULTS

Overall, 75% of patients relapsed into AF during the 3-year study period. AF recurrence was significantly lower in the 1st CRP tertile group (P = 0.039). The Kaplan-Meier survival analysis showed that the rate of AF recurrence was significantly lower in the lowest CRP tertile (log rank; P < 0.001). In a multivariable Cox regression model adjusted for other potential covariates, only CRP (upper two tertiles) was an independent predictor of AF recurrence (heart rate: 6.3, 95% confidence interval: 3.1-12.7, P < 0.001).

CONCLUSIONS

Our findings suggest that baseline CRP levels before EC have an independent prognostic value in predicting the long-term risk of AF recurrence.

Sinus rhythm restoration after atrial fibrillation: the clinical value of N-terminal pro-BNP measurements

AIM

To examine the effects of sinus rhythm (SR) restoration on N-Terminal pro-BNP (NTP-BNP) in patients with atrial fibrillation (AF).

METHODS

Subjects with paroxysmal and persistent AF and absence of organic heart disease were prospectively studied. Chemical or electrical restoration of SR was attempted within 48 hours (n = 37) or >3 weeks (n = 73). Clinical and laboratory (NTP-BNP, 72-hour Holter monitor, and electrocardiogram) assessment were obtained at baseline and at 1, 30, and 180 days after SR restoration. Patients were divided into three predefined "outcome groups": (a) maintenance of SR for 1 month, (b) SR with recurrent paroxysmal AF (PaAF), and (c) early (<30 days) recurrence persistent AF (RAF).

RESULTS

Of the 110 patients enrolled, 89 had initial successful SR restoration. Baseline NTP-BNP was 936 pg/mL (interquartile range (IQR) 333-2,026); ratio between baseline and 30-day NTP-BNP was 10.2 (IQR 6.42-22.0) for SR group, 3.3 (IQR 2.45-7.34) for PaAF, and 1.07 (IQR 0.87-1.22) for RAF (P < 0.001). Patients with ratio </=3 were more likely to have PaAF (46% vs 3%, OR 30, P < 0.001).

CONCLUSION

With SR restoration, NTP-BNP decline is observed up to 1 month. NTP-BNP drop is partially or completely abolished by PaAF and RAF, respectively. NTP-BNP does not predict successful SR restoration.

C-reactive protein but not atrial dysfunction predicts recurrences of atrial fibrillation after cardioversion in patients with preserved left ventricular function

OBJECTIVES

Maintenance of sinus rhythm after cardioversion of atrial fibrillation is a major clinical challenge also in patients with preserved left ventricular function. Subclinical inflammation and atrial strain have been recognized as important contributors to atrial fibrillation onset and perpetuation. Aim of the study was to compare the predictive role of C-reactive protein (CRP) and indices of atrial dysfunction in relation to subacute arrhythmic recurrence rate in patients with persistent atrial fibrillation and normal left ventricular ejection fraction (LVEF).

METHODS

We studied 53 patients with a mean LVEF of 58.7 +/- 6%. Left atrial diameter and area, left atrial auricle emptying velocity, N-terminal pro-b-type natriuretic peptide (NT-proBNP) and CRP levels were determined few hours before electrical cardioversion. NT-proBNP and CRP levels were also measured 1 h and 3 weeks after cardioversion.

RESULTS

Subacute atrial fibrillation recurrences were documented in 18 (33.9%) patients. Whereas none of the parameters reflecting atrial dysfunction predicted arrhythmic outcome, higher CRP levels (>3.0 mg/l) were significantly associated with atrial fibrillation recurrences [odds ratio (OR): 1.6; 95% confidence interval (CI): 1.4-2.5; P = 0.031]. No changes in CRP levels were evident after cardioversion independently of underlying rhythm. On the contrary, NT-proBNP levels, which were correlated with left atrial auricle emptying velocity, significantly decreased only in patients who maintained sinus rhythm (from 638 +/- 329 to 295 +/- 261 pg/ml; P < 0.001).

CONCLUSION

The present study demonstrates that in patients with persistent atrial fibrillation and preserved LVEF, CRP level is an independent predictor of atrial fibrillation subacute recurrence rate, whereas none of the indices of atrial dysfunction is associated with arrhythmic outcome. NT-proBNP levels reflect, instead, the hemodynamic alterations secondary to arrhythmia presence.

NT-ProBNP predicts rhythm stability after cardioversion of lone atrial fibrillation

BACKGROUND

The aim of the present study was: (1) to determine the predictive value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) on the success of an elective direct-current cardioversion; and (2) to assess the ability to monitor rhythm stability after electrical cardioversion in patients with lone atrial fibrillation (AF).

METHODS AND RESULTS

Fifty-three patients with lone AF were provided with an Holter-ECG for a follow-up period of 4 weeks after elective cardioversion. NT-proBNP serum levels were measured before and 4 weeks after cardioversion. All patients presented with increased NT-proBNP serum levels (median 874 pg/ml, interquartile range 703-1,355) before cardioversion. Thirty patients were in sinus rhythm (SR) during follow-up. These patients showed a significant NT-proBNP-decrease (759 pg/ml, 618-1,139 to 318 pg/ml, 200-523, p<0.05). Nineteen patients experienced a relapse of AF. NT-proBNP was significantly higher prior to cardioversion in comparison to patients without relapse (p<0.05) and remained unchanged during follow-up (1,124 pg/ml, 925-1,542 vs 1,256 pg/ml, 945-1,509, p=NS). Four patients had short periods of silent AF detected by Holter ECG. These patients had a smaller decrease in NT-proBNP than patients with stable SR. The area under the curve of the receiver-operating characteristic curve was 0.8 for NT-proBNP to predict a successful cardioversion. Using an optimized cut-off level of 900 pg/ml, successful cardioversion can be predicted with high accuracy.

CONCLUSIONS

The probability of a successful cardioversion correlates inversely with NT-proBNP values. The short-term success of a cardioversion might be predicted by prior determination of NT-proBNP.

Comparison of C-reactive protein levels in patients who do and do not develop atrial fibrillation during electrophysiologic study

C-reactive protein (CRP) was increased in patients with atrial fibrillation (AF). The aim of this study was to evaluate CRP after inducing AF in 39 patients undergoing electrophysiologic study (EPS). After a diagnostic EPS, programmed atrial stimulation with 3 extra stimuli from the right atrium was performed in all patients. CRP was measured before and 6 and 24 hours after the procedure. Patients in whom AF was induced were monitored for 24 hours. AF was induced in 18 of 39 patients. Twenty-one patients without a tachyarrhythmia constituted the control group. Groups were similar with regard to age, gender, incidences of hypertension and diabetes, and history of coronary artery disease. On average, AF lasted 4.8 hours, and spontaneous conversion to sinus rhythm was observed in all patients. There were no statistically significant differences with respect to baseline and 6-hour CRP values between groups. However, mean CRP at 24 hours was significantly higher in patients with AF compared with controls (10 +/- 11 and 3.9 +/- 4.2 mg/L; p = 0.04). In conclusion, induction of AF during EPS led to increased CRP. This finding suggested that increased CRP may be the consequence of AF.

Markers of inflammation before and after curative ablation of atrial flutter

BACKGROUND

Atrial arrhythmias are associated with inflammation. The cause and effect of the association are unknown.

OBJECTIVE

The purpose of this study was to test the hypothesis that atrial tachyarrhythmias contribute to inflammation.

METHODS

We performed a prospective observational study wherein C-reactive protein (CRP) and interleukin-6 (IL-6) levels from the femoral vein and coronary sinus (CS) were compared before curative ablation for atrial flutter (AFL; n = 59) and paroxysmal supraventricular tachycardia (SVT; n = 110). Follow-up levels were obtained at 1 and 6 months.

RESULTS

Peripheral levels of both biomarkers were significantly higher in the AFL group. After multivariate adjustment, only those in the AFL group who presented in AFL or atrial fibrillation (AF) had significantly elevated CRP levels (odds ratio 1.26; P = .033). Levels of each marker were similar in the CS and peripheral blood in the SVT group; in the AFL group, both CRP and IL-6 were significantly lower in the CS than in the periphery (P = .0076 and P = .0021, respectively). CRP was significantly lower a median of 47 days after AFL ablation (from a median of 6.28 mg/L to a median of 2.92 mg/L; P = .028) and remained reduced at second follow-up. IL-6 decreased across three time points after AFL ablation (P = .002). No reduction in inflammatory biomarkers was observed after SVT ablation.

CONCLUSIONS

CRP and IL-6 levels are elevated in patients presenting in AFL. Given the lower CS values in these patients, their origin appears to be systemic rather than cardiac. Because these levels significantly fall after ablation of AFL, the atrial tachyarrhythmia appears to be the cause (not the effect) of the inflammation.

Association between C-reactive protein and recurrence of atrial fibrillation after successful electrical cardioversion: a meta-analysis

OBJECTIVES

We conducted a systematic review and meta-analysis of observational studies to examine the association between baseline C-reactive protein (CRP) levels and the recurrence of atrial fibrillation (AF) after successful electrical cardioversion (EC).

BACKGROUND

Current evidence links AF to the inflammatory state. Inflammatory indexes such as CRP have been related to the development and persistence of AF. However, inconsistent results have been published with regard to the role of CRP in predicting sinus rhythm maintenance after successful EC.

METHODS

Using PubMed, the Cochrane clinical trials database, and EMBASE, we searched for literature published June 2006 or earlier. In addition, a manual search was performed using all review articles on this topic, reference lists of papers, and abstracts from conference reports. Of the 225 initially identified studies, 7 prospective observational studies with 420 patients (229 with and 191 without AF relapse) were finally analyzed.

RESULTS

Overall, baseline CRP levels were greater in patients with AF recurrence. The standardized mean difference in the CRP levels between the patients with, and those without AF was 0.35 units (95% confidence interval 0.01 to 0.69); test for overall effect z-score = 2.00 (p = 0.05). The heterogeneity test showed that there were significant differences between individual studies (p = 0.02; I(2) = 60.2%). Further analysis revealed that differences between the CRP assays possibly account for this heterogeneity.

CONCLUSIONS

Our meta-analysis suggests that increased CRP levels are associated with greater risk of AF recurrence, although there was significant heterogeneity across the studies. The use of CRP levels in predicting sinus rhythm maintenance appears promising but requires further study.

N-terminal pro-brain natriuretic peptide used for the prediction of coronary artery stenosis

BACKGROUND

The level of the inactive N-terminal fragment of pro-brain (B-type) natriuretic peptide (NT-proBNP) is a prognostic marker in patients with acute and chronic coronary artery disease (CAD). It might also be valuable for non-invasive diagnosis of coronary artery disease.

MATERIALS AND METHODS

The NT-proBNP was measured in 781 consecutive patients with normal left ventricular function referred for coronary angiography owing to symptoms or signs of CAD. The diagnostic value of NT-proBNP was assessed for predicting CAD at angiography.

RESULTS

Elevated NT-proBNP levels were associated with the extent of CAD and with the female sex (P < 0.001). The ability of NT-proBNP to predict significant coronary disease at angiography was assessed separately for men using a cut-off point of 85 pg mL(-1), positive likelihood ratio 2.2 (95% CI, 1.7-3.0), negative likelihood ratio 0.53 (95% CI 0.45-0.63) and area under the receiver-operating-characteristic (ROC) curve 0.72: for women, it was assessed using a cut-off point of 165 pg mL(-1), positive likelihood ratio 2.4 (95% CI, 1.7-3.4), negative likelihood ratio 0.55 (95% CI, 0.44-0.70) and area under ROC curve 0.71. In multiple logistic-regression analysis, NT-proBNP added significant independent predictive power to other clinical variables in models predicting CAD (odds ratio 2.76, 95% CI, 1.76-4.32, P < 0.001).

CONCLUSIONS

The NT-proBNP is a marker of non-obstructive CAD and of significant coronary stenosis. In conjunction with other clinical information, measurement of NT-proBNP with the use of sex-specific reference ranges may improve the non-invasive prediction of CAD.