Prognostic Importance of B-Type Natriuretic Peptide Level in Patients Undergoing Catheter Ablation for Atrial Fibrillation

BACKGROUND

This study assessed the prognostic importance of B-type natriuretic peptide (BNP) concentrations for clinical events after catheter ablation for atrial fibrillation (AF).Methods and Results: We enrolled 1,750 consecutive patients undergoing initial AF ablation whose baseline BNP data were available from a large-scale multicenter observational cohort (TRANQUILIZE-AF Registry). The prognostic impact of BNP concentration on clinical outcomes, including recurrent tachyarrhythmias and a composite of heart failure (HF) hospitalization or cardiac death, was evaluated. Median baseline BNP was 94.2 pg/mL. During a median follow-up of 2.4 years, low BNP (<38.3 pg/mL) was associated with lower rates of recurrent atrial tachyarrhythmias than BNP concentrations ≥38.3 pg/mL (19.9% vs. 30.6% at 3 years; P<0.001) and HF (0.8% vs. 5.3% at 3 years; P<0.001). Multivariable Cox regression analyses revealed that low BNP was independently associated with lower risks of arrhythmia recurrence (hazard ratio [HR] 0.63; 95% confidence interval [CI] 0.47-0.82; P<0.001) and HF (HR 0.17; 95% CI 0.04-0.71; P=0.002). The favorable impact of low BNP on arrhythmia recurrence was prominent in patients with paroxysmal, but not non-paroxysmal, AF, particularly among those with long-standing AF.

CONCLUSIONS

Low BNP concentrations had a favorable impact on clinical outcomes after AF ablation. The heterogeneous impact of baseline BNP concentrations on arrhythmia recurrence for the subgroups of patients divided by AF type warrants future larger studies with longer follow-up periods.

Left atrial appendage dimension predicts elevated brain natriuretic peptide in nonvalvular atrial fibrillation

INTRODUCTION

BNP elevation in patients with AF is observed in the absence of heart failure; however, prior mechanistic studies have not included direct left atrial pressure measurements. This study sought to understand how emptying function of the left atrial appendage (LAA) and LAA dimension contributes to brain-natriuretic peptide elevations (BNP) in atrial fibrillation (AF) accounting for left atrial pressure (LAP).

METHODS

132 patients referredfor left atrial appendage occlusion (LAAO) were prospectively enrolled in this study. BNP levels and LAP were measured just before LAAO. Statistical analysis considered BNP, rhythm at time of procedure, LAP, LAA morphology, LAA size (ostial diameter, depth, volume), LAA emptying velocity, CHADS2-VASc score, body mass index (BMI), left ventricular ejection fraction (LVEF), estimated glomerular filtration rate (eGFR), and obstructive sleep apnea (OSA) diagnosis as covariates.

RESULTS

Bivariate statistical analysis demonstrated positive associations with age, LAA ostial diameter, depth, and volume, LAP, AF status at time of measurement, OSA, and CHADS2-VASc score. BNP was negatively associated with LVEF, eGFR, LAA emptying velocity and BMI. With multivariate logistic regression including LAP as covariate, significant relationships between BNP and AF/AFL(OR 1.99 [1.03, 3.85]), LAP (OR 1.13 [1.06, 1.20]), LAA diameter (OR 1.14 [1.03, 1.27]), LAA depth (OR 1.14 [1.07, 1.22]), and LAA emptying velocity (OR 0.97 [0.96,0.99]) were observed; however, no significant associations were seen with LAA morphology or CHADS2-VASc score.

CONCLUSIONS

BNP elevations in AF are associated with LAA size and function, but not CHADS2-VASc score or appendage morphology after accounting for changes in LAP.

NT-pro-BNP as a Predictor for Recurrence of Atrial Fibrillation after Primary Cryoballoon Pulmonary Vein Isolation

NT-pro-BNP is produced in the cardiac atria and ventricles in response to increased wall stress. It may be a marker of both AF disease progression and co-morbidities that affect success after pulmonary vein isolation (PVI). This single-center retrospective study analyzed the association between pre-procedural NT-pro-BNP serum levels and the long-term outcome after a first-ever PVI in cryo-technique. Patients were followed by searching the hospital information system and conducting structured telephone interviews. Treatment failure was defined as any relapse of atrial fibrillation (AF) occurring 90 days after the index PVI at the earliest. Kaplan−Meier survival curves and Cox proportional hazards models were computed to assess the impact of NT-pro-BNP on AF recurrence. Following 374 patients over a median of 3.8 years (range: 0.25−9.4 years), baseline NT-pro-BNP was associated with the combined endpoint in univariate analysis (HR 1.04 per 100 pg/mL increase, 95% CI: 1.02−1.07, p < 0.001). Results were virtually unchanged in the multivariate model or if the data were log-transformed. Intraprocedural left atrial pressure correlated positively with log NT-pro-BNP. NT-pro-BNP was associated with AF relapse during a long-term follow-up after first-ever cryo-PVI in our cohort of patients with predominantly normal left ventricular function. This lab parameter is easy to obtain and has significant potential to guide treatment decisions.

Markers of Inflammation, Oxidative Stress, and Fibrosis in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice. The pathogenesis of AF is linked to inflammatory reaction and oxidative stress, which leads to fibrosis of the atria and progression of the disease. The purpose of this study was to define the role of several biomarkers of inflammation, fibrosis, and oxidative stress (OxS). We included 75 patients with paroxysmal/persistent AF, who were admitted for electrical cardioversion or pulmonary vein isolation (PVI). High-sensitivity C-reactive protein (hsCRP), galectin-3 (Gal-3), myeloperoxidase (MPO), oxidized low-density lipoprotein (oxLDL), and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured before the procedures. We compared the results with those of 75 healthy age-, sex-, and blood pressure-matched individuals. The patients were followed up for 1 year after the intervention to establish the recurrence of AF and its association with the measured markers. Patients with AF had higher MPO (52.6 vs. 36.2 ng/ml, p < 0.001) and NT-proBNP (209.0 vs. 28.0 pg/ml, p < 0.001) compared to healthy subjects. Also, they showed significantly higher levels of hsCRP (1.5 vs. 1.1 mg/l, p = 0.001) and Gal-3 (11.4 vs. 9.7 mg/l, p = 0.003), while there was no difference found in oxLDL (71.5 vs. 71.7 U/l, p = 0.449). MPO (OR = 1.012, p = 0.014), hsCRP (OR = 1.265, p = 0.026), and weight (OR = 1.029, p = 0.013) were independently associated with AF in a multivariable logistic regression analysis. Patients with successful maintenance of sinus rhythm (SR) for one year had lower baseline MPO (40.5 vs. 84.3 ng/ml, p = 0.005) and NT-proBNP (127.5 vs. 694.0 pg/ml, p < 0.001) compared to patients with recurrent AF episodes, but there was no difference in hsCRP, Gal-3, or oxLDL between them. MPO (OR = 0.985, p = 0.010) was independently associated with AF recurrence during the follow-up period when adjusted for cofounders. Patients with AF had increased markers of inflammation and fibrosis, while there was no increase detected in the OxS marker oxLDL. MPO was independently associated with AF in a multivariate model. Inflammatory and fibrotic mechanisms are important factors in electrical and structural remodelling progress in the atria of patients with AF.

Biomarkers as predictors of recurrence of atrial fibrillation post ablation: an updated and expanded systematic review and meta-analysis

Background

A high proportion of patients undergoing catheter ablation (CA) for atrial fibrillation (AF) experience recurrence of arrhythmia. This meta-analysis aims to identify pre-ablation serum biomarker(s) associated with arrhythmia recurrence to improve patient selection before CA.

Methods

A systematic approach following PRISMA reporting guidelines was utilised in libraries (Pubmed/Medline, Embase, Web of Science, Scopus) and supplemented by scanning through bibliographies of articles. Biomarker levels were compared using a random-effects model and presented as odds ratio (OR). Heterogeneity was examined by meta-regression and subgroup analysis.

Results

In total, 73 studies were identified after inclusion and exclusion criteria were applied. Nine out of 22 biomarkers showed association with recurrence of AF after CA. High levels of N-Terminal-pro-B-type-Natriuretic Peptide [OR (95% CI), 3.11 (1.80–5.36)], B-type Natriuretic Peptide [BNP, 2.91 (1.74–4.88)], high-sensitivity C-Reactive Protein [2.04 (1.28–3.23)], Carboxy-terminal telopeptide of collagen type I [1.89 (1.16–3.08)] and Interleukin-6 [1.83 (1.18–2.84)] were strongly associated with identifying patients with AF recurrence. Meta-regression highlighted that AF type had a significant impact on BNP levels (heterogeneity R² = 55%). Subgroup analysis showed that high BNP levels were more strongly associated with AF recurrence in paroxysmal AF (PAF) cohorts compared to the addition of non-PAF patients. Egger’s test ruled out the presence of publication bias from small-study effects.

Conclusion

Ranking biomarkers based on the strength of association with outcome provides each biomarker relative capacity to predict AF recurrence. This will provide randomised controlled trials, a guide to choosing a priori tool for identifying patients likely to revert to AF, which are required to substantiate these findings.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01978-w.

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Deep Learning-Based Recurrence Prediction of Atrial Fibrillation After Catheter Ablation

BACKGROUND

Radiofrequency catheter ablation (RFCA) is an effective therapy for atrial fibrillation (AF). However, it the problem of AF recurrence remains. This study investigates whether a deep convolutional neural network (CNN) can accurately predict AF recurrence in patients with AF who underwent RFCA, and compares CNN with conventional statistical analysis.Methods and Results:Three-hundred and ten patients with AF after RFCA treatment, including 94 patients with AF recurrence, were enrolled. Nine variables are identified as candidate predictors by univariate Cox proportional hazards regression (CPH). A CNNSurv model for AF recurrence prediction was proposed. The model's discrimination ability is validated by a 10-fold cross validation method and measured by C-index. After back elimination, 4 predictors are used for model development, they are N-terminal pro-BNP (NT-proBNP), paroxysmal AF (PAF), left atrial appendage volume (LAAV) and left atrial volume (LAV). The average testing C-index is 0.76 (0.72-0.79). The corresponding calibration plot appears to fit well to a diagonal, and the P value of the Hosmer-Lemeshow test also indicates the proposed model has good calibration ability. The proposed model has superior performance compared with the DeepSurv and multivariate CPH. The result of risk stratification indicates that patients with non-PAF, higher NT-proBNP, larger LAAV and LAV would have higher risks of AF recurrence.

CONCLUSIONS

The proposed CNNSurv model has better performance than conventional statistical analysis, which may provide valuable guidance for clinical practice.

The role of brain natriuretic peptide in atrial fibrillation: a substudy of the Substrate Modification with Aggressive Blood Pressure Control for Atrial Fibrillation (SMAC-AF) trial

BACKGROUND

Catheter ablation is an established therapy for atrial fibrillation but is limited by recurrence; efforts have been made to identify biomarkers that predict recurrence. We investigated the effect of baseline NT-proBNP on AF recurrence following catheter ablation in patients randomized to aggressive (< 120/80 mmHg) or standard blood pressure management (< 140/90 mmHg) in the Substrate Modification with Aggressive Blood Pressure Control trial (SMAC-AF).

METHODS

The SMAC-AF study included 173 patients resistant or intolerant to at least one class I or III antiarrhythmic drug. We studied the effect of baseline NT-proBNP on the primary outcome of AF recurrence > 3 months post-ablation.

RESULTS

Of the 173 patients, 88 were randomized to the aggressive cohort, and 85 into the standard group. The primary outcome occurred in 61.4% of those in the aggressive arm, versus 61.2% in the standard arm. In the aggressive group, logNT-proBNP predicted recurrence (HR 1.28, p = 0.04, adjusted HR 1.43, p = 0.03), while in the standard cohort, it did not (HR 0.94, p = 0.62, adjusted HR 0.83, p = 0.22). NT-proBNP ≥ 280 pg/mL also predicted occurrence in the aggressive (HR 1.98, p = 0.02) but not the standard cohort (HR 1.00, p = 1.00).

CONCLUSION

We conclude that pre-ablation NT-proBNP may be useful in predicting recurrence in hypertensive patients and identifying patients who benefit from aggressive blood control and upstream therapies.

TRIAL REGISTRATION

NCT00438113, registered February 21, 2007.

Plasma carbohydrate antigen-125 for prediction of atrial fibrillation recurrence after radiofrequency catheter ablation

Background

Elevated plasma carbohydrate antigen-125 (CA-125) levels are strongly associated with new-onset atrial fibrillation (AF) and heart failure, but the relationship between plasma CA-125 level and AF recurrence following radiofrequency catheter ablation (RFCA) remains poorly investigated. We aimed to assess whether elevated CA-125 levels are related to long-term AF recurrence following RFCA.

Methods

Preoperative CA-125 levels were determined in AF patients undergoing initial RFCA. Multivariate-adjusted Cox models were constructed to determine the relationship between CA-125 levels and AF recurrence. Multivariate logistic regression analyses were performed to determine predictors of AF recurrence.

Results

Of the 353 enrolled patients, 85 patients (24.1%) had AF recurrence at the 12-month follow-up. These patients had significantly higher baseline CA-125 levels than those without AF recurrence [(18.71 ± 12.63) vs. (11.27 ± 5.40) U/mL, P < 0.001]. The incidence of AF recurrence across quartiles 1–4 of CA-125 was 11.5%, 13.3%, 21.6% and 50.0%, respectively (P-trend < 0.001). The adjusted hazard ratios (aHRs) for AF recurrence across quartiles 1–4 of CA-125 were 1.00 (reference), 1.085 (95% CI, 0.468–2.520), 1.866 (95% CI, 0.867–4.019), and 4.246 (95% CI, 2.113–8.533), respectively (P-trend < 0.001). A similar effect was obtained when CA-125 was studied as continuous data (aHR per unit increase in LnCA-125, 3.225, 95% CI, 2.258–4.606; P < 0.001). When a predefined CA-125 cut-off of 13.75 U/mL was established, patients with CA-125 ≥ 13.75 U/mL had a higher risk of recurrent AF than those with CA-125 < 13.75 U/mL (aHR, 3.540, 95% CI, 2.268–5.525, P < 0.001). Multivariate analysis revealed CA-125, high-sensitivity C-reactive protein, and left atrium anteroposterior diameter as independent risk factors for AF recurrence.

Conclusions

Elevated preoperative CA-125 levels are related to a higher risk of AF recurrence and can independently predict AF recurrence following RFCA.

Is There an Association between Epicardial Adipose Tissue and Outcomes after Paroxysmal Atrial Fibrillation Catheter Ablation?

Background: In patients undergoing paroxysmal atrial fibrillation (PAF) ablation, pulmonary vein isolation (PVI) alone fails in maintaining sinus rhythm in up to one third of patients after a first catheter ablation. Epicardial adipose tissue (EAT), as an endocrine-active organ, could play a role in the recurrence of AF after catheter ablation. Objective: To evaluate the predictive value of clinical, echocardiographic, biological parameters and epicardial fat density measured by computed tomography scan (CT-scan) on AF recurrence in PAF patients who underwent a first pulmonary vein isolation procedure using radiofrequency (RF). Methods: This monocentric retrospective study included all patients undergoing first-time RF PAF ablation at the Nancy University Hospital between March 2015 and December 2018 with one-year follow-up. Results: 389 patients were included, of whom 128 (32.9%) had AF recurrence at one-year follow-up. Neither total-EAT volume (88.6 ± 37.2 cm³ vs. 91.4 ± 40.5 cm³, p = 0.519), nor total-EAT radiodensity (−98.8 ± 4.1 HU vs. −98.8 ± 3.8 HU, p = 0.892) and left atrium-EAT radiodensity (−93.7 ± 4.3 HU vs. −93.4 ± 6.0 HU, p = 0.556) were significantly associated with AF recurrence after PAF ablation. In multivariate analysis, previous cavo-tricuspid isthmus (CTI) ablation, ablation procedure duration, BNP and triglyceride levels remained independently associated with AF recurrence after catheter ablation at 12-months follow-up. Conclusion: Contrary to persistent AF, EAT parameters are not associated with AF recurrence after paroxysmal AF ablation. Thus, the role of the metabolic atrial substrate in PAF pathophysiology appears less obvious than in persistent AF.

Defibrillation threshold of internal cardioversion prior to ablation predicts atrial fibrillation recurrence

BACKGROUND

Many studies have reported the predictors of atrial fibrillation (AF) recurrence after persistent AF (peAF) ablation. However, the correlation between the atrial defibrillation threshold (DFT) for internal cardioversion (IC) and AF recurrence rate is unknown. Here we investigated the relationship between the DFT prior to catheter ablation for peAF and AF recurrence.

HYPOTHESIS

DFT prior to ablation was the predictive factor for AF recurrence after peAF ablation.

METHODS

From June 2016 to May 2019, we enrolled 82 consecutive patients (mean age, 65.0 ± 12.4 years), including 45 with peAF and 37 with long-standing peAF, at Hamamatsu Medical Center. To assess the DFT, we performed IC with gradually increasing energy prior to radiofrequency application.

RESULTS

Forty-nine and 33 patients showed DFT values less than or equal to 10 J (group A) and greater than 10 J or unsuccessful defibrillation (group B). During the mean follow-up duration of 20.5 ± 13.1 months, patients in group B showed significantly higher AF recurrence rates than those in group A after the ablation procedure (p = .017). Multivariate analysis revealed that DFT was the only predictive factor for AF recurrence (odds ratio, 1.07; 95% CI, 1.00-1.13, p = .047).

CONCLUSIONS

The DFT for IC was among the strongest prognostic factors in the peAF ablation procedure.

Usefulness of Post-Procedural Plasma Brain Natriuretic Peptide Levels to Predict Recurrence After Catheter Ablation of Atrial Fibrillation in Patients With Left Ventricular Systolic Dysfunction

Catheter ablation (CA) of atrial fibrillation (AF) improves cardiac function, resulting in a decrease in plasma brain natriuretic peptide (BNP) levels in patients with reduced left ventricular ejection fraction (LVEF). This study sought to examine the pre-procedural and post-procedural correlations between BNP levels and cardiac function and the associations between the BNP levels and recurrence after CA in patients with AF and reduced LVEF. Of 3142 consecutive patients who underwent first-time CA of AF at our institute, a total of 217 patients with LVEF <50% were enrolled. Significant decrease in BNP levels (from a median of 198 [interquartile range 113 to 355] to 47.7 [22.7 to 135] pg/ml, p <0.001) and improvement in LVEF (from 39±9% to 61±16%, p <0.001) were observed 3 months after CA. There was a linear correlation between log-transformed BNP levels and cardiac measures (LVEF: r = -0.64; LV end-diastolic volume: r = 0.25; LV end-systolic volume: r = 0.43; left atrial volume: r = 0.52; all p <0.001). During a median follow-up of 35 months, AF recurrence after a 3-month blanking period was observed in 80 patients (37%). Cox proportional hazard regression analysis after adjustment for cardiac measures significant in univariate analysis revealed that early recurrence within the blanking period (hazard ratio, 4.88; 95% confidence interval, 2.89 to 8.25) and elevated post-procedural BNP levels (2.02 per unit log increase; 1.14 to 3.56) were significant predictors of AF recurrence, but pre-procedural BNP was not. In conclusion, post-procedural BNP levels at the end of the blanking period predicted subsequent AF recurrence in patients with reduced LVEF, independent of early recurrence.

A predictive model using left atrial function and B-type natriuretic peptide level in predicting the recurrence of early persistent atrial fibrillation after radiofrequency ablation

Aim

A predictive model using left atrial function indexes obtained by real‐time three‐dimensional echocardiography (RT‐3DE) and the blood B‐type natriuretic peptide (BNP) level was constructed, and its value in predicting recurrence in patients with early persistent atrial fibrillation (AF) after radiofrequency ablation was explored.

Methods

A total of 228 patients with early persistent AF who were scheduled to receive the first circular pulmonary vein ablation (CPVA) were enrolled. Clinical data of patients were collected: (1) The blood BNP level was measured before radiofrequency ablation; (2) RT‐3DE was used to obtain the left atrial (LA) time‐volume curve; (3) The clinical characteristics, BNP level and LA function parameters were compared, and logistic regression was used to construct a prediction model with combined parameters; (4) The receiver operating characteristic (ROC) curve was used to examine the diagnostic efficacy of the model.

Results

(1) 215 patients with early persistent AF completed CPVA and the follow‐up. After 3–6 months of follow‐up, the patients were divided into sinus rhythm group (160 cases) and recurrence group (55 cases); (2) The recurrence group showed higher minimum LA volume index, diastolic ejection index, and preoperative BNP (all p ≤ .001), while the sinus rhythm group exhibited higher expansion index (PI) and left atrial appendage peak emptying velocity (p ≤ .001); (3) In univariate analysis, BNP level had the best diagnostic performance in predicting the recurrence of AF(AUC = 0.703). We constructed a model based on LA function and BNP level to predict the recurrence of persistent AF after CPVA. This combined model was better than BNP alone in predicting the recurrence of persistent AF after CPVA (AUC: 0.814 vs. 0.703, z = 2.224, p = .026).

Conclusion

The combined model of LA function and blood BNP level has good predictive value for the recurrence of early persistent AF after CPVA.

Decreased plasma musclin levels are associated with potential atrial fibrillation in non-diabetic patients

Background

Musclin is involved in the regulation of natriuretic peptide (NP) clearance and may affect the concentration of atrial natriuretic peptide (ANP). It has also been found to play an important role in several diseases, such as diabetes mellitus and hypertension. Both abnormalities in ANP and associated medical history are involved in the pathogenesis of atrial fibrillation (AF). However, plasma concentration of musclin as a biomarker for risk stratification in patients with AF has not been fully investigated.

Methods

Plasma musclin levels were measured in 290 patients with AF (including 199 paroxysmal AF patients and 91 persistent AF patients) and 120 control subjects. The association between plasma musclin levels and AF onset, as well as its predictive effects on clinical outcomes after cryoballoon ablation were analyzed.

Results

AF patients were found to have a lower concentration of plasma musclin than healthy controls. Moreover, in the non-diabetic group and normal N-terminal pro-brain natriuretic peptide (NT-proBNP) level group, the association between lower plasma concentration of musclin and AF remained significant. According to receiver operating characteristic (ROC) curve analysis, the optimal cut-off point of musclin for predicting AF onset was 54.94 ng/mL, which had a sensitivity of 81.67% and a specificity of 31.47% [area under the ROC curve (AUC) =60.71%]. In follow-up studies, both diabetes and left atrial size were independent predictors of AF recurrence after ablation, while musclin showed only a modest relationship with the outcome of cryoballoon ablation.

Conclusions

Our data indicated that decreased musclin was associated with the onset of AF. Moreover, lower plasma levels of musclin were an independent risk factor of AF in non-diabetic patients. Our studies suggest that musclin could be a predictive factor for the onset of AF.

High Brain Natriuretic Peptide Level Predicts The Prevalence Of Low-Voltage Areas And Poor Rhythm Outcome In Patients Undergoing Atrial Fibrillation Ablation

Backgrounds

The prevalence of residual left atrial low-voltage areas (LVAs) is associated with atrial fibrillation (AF) recurrence after pulmonary vein isolation. Brain natriuretic peptide (BNP) may be increased in AF patients and may raise AF recurrence risk after catheter ablation. We investigated the association between BNP and the prevalence of LVAs.

Methods

One hundred and eighty three consecutive AF cases were retrospectively enrolled that underwent initial ablation for AF (persistent AF, 82 [45%] patients). Serum BNP was measured before ablation and the natural logarithm of BNP (log-BNP) was calculated. Low-voltage points were defined as sites with left atrial electrogram amplitude <0.5 mV. LVAs were defined as regions with ≥5% low-voltage points across the total surface area of the left atrium.

Results

Of the 183 patients, 38 (21%) had LVAs. Patients with LVAs demonstrated higher log-BNP (4.8±0.9 vs. 3.9±1.2, P<0.001). The optimal cut-off value of log-BNP was 4.4, which was equivalent to 81 pg/mL of BNP. LVAs were more frequent in patients with higher log-BNP. In multivariate analysis, log-BNP >4.4 was an independent predictor of LVAs (odds ratio 2.7 [95% confidence interval 1.01-7.1], P=0.048). Freedom from AF recurrence was significantly lower in patients with than without high log-BNP (P=0.007).

Conclusions

BNP correlated with the prevalence of left atrial LVAs and AF recurrence in patients with AF undergoing catheter ablation.

Molecular Mechanisms, Diagnostic Aspects and Therapeutic Opportunities of Micro Ribonucleic Acids in Atrial Fibrillation

Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules responsible for regulation of gene expression. They are involved in many pathophysiological processes of a wide spectrum of diseases. Recent studies showed their involvement in atrial fibrillation. They seem to become potential screening biomarkers for atrial fibrillation and even treatment targets for this arrhythmia. The aim of this review article was to summarize the latest knowledge about miRNA and their molecular relation to the pathophysiology, diagnosis and treatment of atrial fibrillation.

Modulation of SERCA in Patients with Persistent Atrial Fibrillation Treated by Epicardial Thoracoscopic Ablation: The CAMAF Study

OBJECTIVES

To evaluate atrial fibrillation (AF) recurrence and Sarcoplasmic Endoplasmic Reticulum Calcium ATPase (SERCA) levels in patients treated by epicardial thoracoscopic ablation for persistent AF.

BACKGROUND

Reduced levels of SERCA have been reported in the peripheral blood cells of patients with AF. We hypothesize that SERCA levels can predict the response to epicardial ablation.

METHODS

We designed a prospective, multicenter, observational study to recruit, from October 2014 to June 2016, patients with persistent AF receiving an epicardial thoracoscopic pulmonary vein isolation.

RESULTS

We enrolled 27 patients. Responders (n = 15) did not present AF recurrence after epicardial ablation at one-year follow-up; these patients displayed a marked remodeling of the left atrium, with a significant reduction of inflammatory cytokines, B type natriuretic peptide (BNP), and increased levels of SERCA compared to baseline and to nonresponders (p < 0.05). Furthermore, mean AF duration (Heart rate (HR) 1.235 (1.037-1.471), p < 0.05), Left atrium volume (LAV) (HR 1.755 (1.126-2.738), p < 0.05), BNP (HR 1.945 (1.895-1.999), p < 0.05), and SERCA (HR 1.763 (1.167-2.663), p < 0.05) were predictive of AF recurrence.

CONCLUSIONS

Our data indicate for the first time that baseline values of SERCA in patients with persistent AF might be predictive of failure to epicardial ablative approach. Intriguingly, epicardial ablation was associated with increased levels of SERCA in responders. Therefore, SERCA might be an innovative therapeutic target to improve the response to epicardial ablative treatments.

Echocardiographic and Biochemical Factors Predicting Arrhythmia Recurrence After Catheter Ablation of Atrial Fibrillation-An Observational Study

Background: RFA is a well-established treatment for symptomatic patients with AF. However, the success rate of a single procedure is low. We aimed to investigate the association between the risk of recurrence of atrial fibrillation (AF) after a single radiofrequency ablation (RFA) procedure and cardiac neurohormonal function, left atrial (LA) mechanical function as well as proteins related to inflammation, fibrosis, and apoptosis.

Methods and Results: We studied 189 patients undergoing RFA between January 2012 and April 2014, with a follow-up period of 12 months. A logistic regression analysis was performed to investigate the association between pre-ablation LA emptying fraction (LAEF), MR-proANP, Caspase-8 (CASP8), Neurotrophin-3 (NT3), and the risk for recurrence of AF after a single RFA procedure. 119 (63.0%) patients had a recurrence during a mean follow-up of 402 ± 73 days. An increased risk of recurrence was associated with: Elevated MR-proANP (fourth quartile vs. first quartile: HR, 2.80 (95% CI, 1.14–6.90]; P = 0.025); Low LAEF (fourth quartile vs. first quartile: hazard ratio [HR], 2.41 [95% CI, 1.01–5.79]; P = 0.045); Elevated CASP8 (fourth quartile vs. first quartile: HR 12.198 95% CI 2.216–67.129; P = 0.004); Elevated NT-3 (fourth quartile vs. first quartile: HR 7.485 95% CI 1.353–41.402; P = 0.021). In a receiver operating characteristic curve analysis, the combination of MR-proANP, CASP8, and NT3 produced an area under the curve of 0.819; CI 95% (0.710–0.928).

Conclusions: Patients with better LA mechanical function and lower levels of atrial neurohormones as well as of proteins related to fibrosis and apoptosis, have a better outcome after an RFA procedure.

Unique identifier: No. NCT01553045 (https://clinicaltrials.gov/ct2/show/NCT01553045?term=NCT01553045&rank=1).

Clinical Applications of Natriuretic Peptides in Heart Failure and Atrial Fibrillation

Natriuretic peptides (NPs) have become important diagnostic and prognostic biomarkers in cardiovascular diseases, particularly in heart failure (HF). Diagnosis and management of coronary artery disease and atrial fibrillation (AF) can also be guided by NP levels. When interpreting NP levels, however, the caveat is that age, sex, body mass index, renal dysfunction, and race affect the clearance of NPs, resulting in different cut-off values in clinical practice. In AF, NP levels have been associated with incident AF in the general population, recurrences after catheter ablation, prediction of clinical prognosis, and the risk of stroke. In this article, we first review and summarize the current evidence and the roles of B-type NP and atrial NP in HF and coronary artery disease and then focus on the increasing utility of NPs in the diagnosis and management of and the research into AF.

B-type natriuretic peptide enhances fibrotic effects via matrix metalloproteinase-2 expression in the mouse atrium in vivo and in human atrial myofibroblasts in vitro

B-type natriuretic peptide (BNP) was approved by the US Food and Drug Administration in 2001 for the treatment of heart failure. However, the effects of BNP in clinical applications are controversial and uncertain. Recently, study indicated that high BNP levels are associated with an increased risk of developing atrial fibrillation. In this study, we investigated the direct effects of BNP on TNF-α-induced atrial fibrosis mice, as well as its effects on human atrial myofibroblasts. We found that injecting TNF-α-induced mice with recombinant human BNP enhanced atrial fibrosis via matrix metalloproteinase-2 (MMP-2) expression and collagen accumulation. Furthermore, we found that BNP stimulated MMP-2 expression in human atrial myofibroblasts. Treatment of human atrial myofibroblasts with cycloheximide had no effect on this outcome; however, treatment of cells with MG132 enhanced BNP-induced MMP-2 expression, indicating that protein stability and inhibition of proteasome-mediated protein degradation pathways are potentially involved. Inhibition of SIRT1 significantly decreased BNP-induced MMP-2 expression. Additionally, confocal and coimmunoprecipitation data indicated that BNP-regulated MMP-2 expression are likely to be mediated through direct interaction with SIRT1, which is thought to deacetylate MMP-2 and to increase its protein stability in human atrial myofibroblasts. Finally, we confirmed that SIRT1 is expressed and cytoplasmically redistributed as well as colocalized with MMP-2 in mouse fibrotic atrial tissue. We suggest a possible fibrosis-promoting role of BNP in the atrium, although the antifibrotic properties of BNP in the ventricle have been reported in previous studies, and that the coordination between MMP-2 and SIRT1 in BNP-induced atrial myofibroblasts participates in atrial fibrosis.

Prediction and Management of Recurrences after Catheter Ablation in Atrial Fibrillation and Heart Failure

Catheter ablation is recommended in patients with symptomatic atrial fibrillation (AF) refractory to pharmacologic therapy. AF recurrence is common postablation, particularly in patients with heart failure, because of multiple structural and functional changes that can occur. Determining predictors of AF recurrence has become increasingly important. These include increased left atrial volume, termination of AF during the index ablation, electrocardiogram parameters, and serum biomarkers. Cardiac MRI can also determine the degree of scarring and left atrial sphericity, which is used in risk prediction scores. In patients with recurrence, further treatment options include pharmacologic therapy and atrioventricular nodal ablation with pacing.

Immunopathogenesis and biomarkers of recurrent atrial fibrillation following ablation therapy in patients with preexisting atrial fibrillation

INTRODUCTION

Recurrent atrial fibrillation (RAF) following ablation therapy occurs in about 50% of patients. The pathogenesis of RAF is unknown, but is believed to be driven by atrial remodeling in the setting of background inflammation. Structural, electrophysiological and mechanical remodeling has been associated with atrial fibrillation (AF). Inflammation and fibrotic remodeling are the major factors perpetuating AF, as mediators released from the atrial tissues and cardiomyocytes due to mechanical and surgical injury could initiate the inflammatory process. In this article, we have critically reviewed the key mediators that may serve as potential biomarkers to predict RAF. Areas covered: Damage associated molecular patterns, heat shock proteins, inflammatory cytokines, non-inflammatory markers, markers of inflammatory cell activity, and markers of collagen deposition and metabolism are evaluated as potential biomarkers with molecular treatment options in RAF. Expert commentary: Establishing biomarkers to predict RAF could be useful in reducing morbidity and mortality. Investigations into the role of DAMPs participating in a sterile immune response may provide greater insight into the pathogenesis of RAF. Markers evaluating immune cell activity, collagen deposition, and levels of heat shock proteins show the greatest promise as potential biomarkers to predict RAF and develop novel therapies.

Radiofrequency catheter ablation for paroxysmal atrial fibrillation: outcomes during a 3-year follow-up period

Objective

This study was performed to observe the effect of radiofrequency catheter ablation (RFCA) in patients with paroxysmal atrial fibrillation (PAF) and to explore the risk factors for late recurrence of atrial fibrillation (LRAF) after a single RFCA session.

Methods

In this retrospective study, 243 patients with PAF underwent RFCA and were followed up regularly.

Results

At a median follow-up of 37 months after a single procedure, 60.5% of patients maintained sinus rhythm (SR), and at a median follow-up of 42 months after multiple procedures, 74.9% of patients maintained SR. The statistically significant risk factors for LRAF after a single RFCA session were the left atrial diameter (LAD), left inferior pulmonary vein superior–inferior diameter (LIPV SID), PV number variation, circumferential pulmonary vein isolation (CPVI) combined with additional ablation, and early recurrence of atrial fibrillation (ERAF). The best cut-off value for LAD was 35.5 mm.

Conclusions

During a 3-year follow-up, about 70% of the patients with PAF maintained SR. LRAF after a single procedure was associated with the LAD, LIPV SID, PV number variation, CPVI combined with additional ablation, and ERAF.

Antithrombotic Treatment May Reduce Mortality Among New-Onset Atrial Fibrillation Patients with Gray-Zone Risk of Stroke

In clinical practice, some atrial fibrillation (AF) patients were classified as having low and moderate stroke risk by the CHADS₂ score (≤ 1) in 2001 but in 2012 they were not truly classified as low risk of stroke according to the CHA₂DS₂-VASc score (≥ 2) (defined gray zone). Therefore, a treatment gap exists in gray zone AF patients. This study aimed to evaluate whether gray zone AF patients could benefit from reduced all-cause mortality under antithrombotic treatment. This was a longitudinal cohort study performed using data from claim forms submitted to the Taiwan Bureau of National Health Insurance from January 2000 to December 2011. The new-onset AF patients consisted of a gray zone cohort with a total of 1237 patients being enrolled. The primary outcome was all-cause mortality between 2001 and 2011. Patients in the gray zone receiving antithrombotic treatment had a significant reduction in all-cause mortality [hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.16-0.28] compared with the no treatment group [warfarin only: HR, 0.28 (95% CI, 0.15-0.52); warfarin + Aspirin: HR, 0.21 (95% CI, 0.15-0.30); and Aspirin only: HR, 0.22 (95% CI, 0.16-0.29) ]. All-cause mortality was notably increased when any of the following risk factors were present: age 65-74 years, age ≥ 75 years, chronic kidney disease, and vascular disease. We concluded that AF patients in the gray zone must receive either anticoagulant and/or antiplatelet treatment and there is a lower mortality in these groups during long-term follow-up. Further investigation is needed to observe whether the antithrombotic drugs have benefits for patients with AF with a CHA₂DS₂-VASc score < 2.

Pre-ablation levels of brain natriuretic peptide are independently associated with the recurrence of atrial fibrillation after radiofrequency catheter ablation in patients with nonvalvular atrial fibrillation

Association between pre-ablation levels of biomarkers of cardiac and endothelial dysfunctions, CHADS2, CHA2DS2-VASc, and APPLE scores and the recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation has not been fully studied. A total of 254 patients with nonvalvular AF were prospectively followed for AF recurrence after a single ablation procedure. During a two-year follow-up period, AF recurred in 65 (25.6%) patients. Patients with AF recurrence had significantly greater baseline ln brain natriuretic peptide (BNP) than those without AF recurrence (P < 0.01), whereas there were no significant differences in the levels of biomarkers of endothelial dysfunction and points of scoring systems. In the Cox regression analyses, the baseline ln BNP was significantly independently associated with AF recurrence (adjusted HR =1.286, 95% CI =1.000–1.655, P < 0.05). The baseline levels of ln BNP were significantly associated with rhythm at blood collection, age, sex, and left atrial diameter, and left ventricular ejection fraction (P < 0.05).The subgroup analysis showed a significant interaction on the risk of AF recurrence between ln BNP, sex difference, and rhythm at blood collection (P for interaction < 0.05). In conclusion, the results suggest that the pre-ablation levels of ln BNP are useful to evaluate the risk of AF recurrence after ablation therapy; however, there is a need to be careful while using BNP as a biomarker for the risk of AF recurrence by taking account of the effects of rhythm status at blood collection and sex difference.

Clinical Characteristics and Mid-Term Outcomes of Non-Elderly Obese Patients with Acute Decompensated Heart Failure in Japan

Obesity is a well-known risk factor for cardiovascular diseases including heart failure (HF). However, some literatures suggested better clinical outcomes in obese patients with HF. Since higher body mass index (BMI) levels of HF patients were significantly associated with younger age, the impact of obesity on clinical outcomes in non-elderly HF patients should be elucidated.Consecutive 155 non-elderly acute decompensated HF patients (< 60-year-old) who admitted to our institution between 2009 and 2013 were included. Those patients were divided into the two groups according to the BMI: the obesity group (BMI ≥ 25 kg/m², n = 81) and the non-obesity group (BMI < 25 kg/m², n = 74). The primary composite outcome of this study was defined as re-admission due to HF and all-cause death.The primary composite outcome was less frequently observed in the obesity group as compared with the non-obesity group (Hazard ratio [HR] 0.50, 95% confidence interval [CI] 0.26-0.95, P = 0.03). Re-admission due to HF was significantly less in the obesity group than in the non-obesity group (HR 0.44, 95% CI 0.23-0.86, P = 0.02), whereas all-cause death was not significantly different between the groups (P = 0.44).The mid-term outcomes in non-elderly HF patients with obesity were better as compared with non-elderly HF patients without obesity, which supports obesity paradox in this specific population.

Angiotensin converting enzyme 2 activity and human atrial fibrillation: increased plasma angiotensin converting enzyme 2 activity is associated with atrial fibrillation and more advanced left atrial structural remodelling

Aim

Angiotensin converting enzyme 2 (ACE2) is an integral membrane protein whose main action is to degrade angiotensin II. Plasma ACE2 activity is increased in various cardiovascular diseases. We aimed to determine the relationship between plasma ACE2 activity and human atrial fibrillation (AF), and in particular its relationship to left atrial (LA) structural remodelling.

Methods and results

One hundred and three participants from a tertiary arrhythmia centre, including 58 with paroxysmal AF (PAF), 20 with persistent AF (PersAF), and 25 controls, underwent clinical evaluation, echocardiographic analysis, and measurement of plasma ACE2 activity. A subgroup of 20 participants underwent invasive LA electroanatomic mapping. Plasma ACE2 activity levels were increased in AF [control 13.3 (9.5-22.3) pmol/min/mL; PAF 16.9 (9.7-27.3) pmol/min/mL; PersAF 22.8 (13.7-33.4) pmol/min/mL, P = 0.006]. Elevated plasma ACE2 was associated with older age, male gender, hypertension and vascular disease, elevated left ventricular (LV) mass, impaired LV diastolic function and advanced atrial disease (P < 0.05 for all). Independent predictors of elevated plasma ACE2 activity were AF (P = 0.04) and vascular disease (P < 0.01). There was a significant relationship between elevated ACE2 activity and low mean LA bipolar voltage (adjusted R2 = 0.22, P = 0.03), a high proportion of complex fractionated electrograms (R2 = 0.32, P = 0.009) and a long LA activation time (R2 = 0.20, P = 0.04).

Conclusion

Plasma ACE2 activity is elevated in human AF. Both AF and vascular disease predict elevated plasma ACE2 activity, and elevated plasma ACE2 is significantly associated with more advanced LA structural remodelling.

Left atrial strain assessed by three-dimensional speckle tracking echocardiography predicts atrial fibrillation recurrence after catheter ablation in patients with paroxysmal atrial fibrillation

BACKGROUND

Several studies have shown the utility of left atrial (LA) function determined by two-dimensional or three-dimensional speckle tracking echocardiography (2D- or 3D-STE) for identifying patients with paroxysmal atrial fibrillation (AF). However, whether 3D-STE is applicable for prediction of the recurrence of AF after catheter ablation (CA) remains unknown. We examined whether any 3D-STE parameters are better than 2D-STE parameters for the prediction of AF recurrence.

METHODS

Forty-two patients with paroxysmal AF (58 ± 10 years old, 69% male) underwent 2D- and 3D-STE within 3 days before first-time CA. The global peak LA longitudinal, circumferential, and area strains during systole (3D-GLSs, -GCSs, and -GASs, respectively) and those just before atrial contraction (3D-GLSa, -GCSa, and -GASa, respectively) were determined by 3D-STE and standard deviations of times to peaks of regional LA strains were calculated as indices of LA dyssynchrony. In 2D-STE, global LA longitudinal strains during systole and just before atrial contraction (2D-GLSs and -GLSa) were determined.

RESULTS

During follow-up of 441 ± 221 days, 12 patients (29%) had AF recurrence. In the univariate Cox proportional hazard analysis, age [hazard ratio (HR): 1.08, p = 0.04], 3D-GCSs (HR: 0.91, p = 0.03), and 3D-GASs (HR: 0.95, p = 0.01) were predictors of AF recurrence, though associations of recurrence with 2D-STE parameters, indices of LA synchrony, and LA volume were not significant. Multivariable analysis showed that 3D-GASs was an independent predictor of AF recurrence (HR: 0.96, p = 0.048).

CONCLUSIONS

LA strain determined by 3D-STE is a novel and better predictor of AF recurrence after CA than that determined by 2D-STE or other known predictors.