Time course of markers of tissue repair after ablation of atrial fibrillation and their relation to left atrial structural changes and clinical ablation outcome

Interleukin-11 Is Elevated in Patients with Atrial Fibrillation, Correlates with Serum Fibrosis Markers, and Represents a Therapeutic Target for Atrial Fibrosis

INTRODUCTION

Inflammatory cytokines are closely associated with developing cardiac fibrosis. This research aimed to explore the significant role of IL-11 in atrial fibrosis progression and potential therapeutic targets.

METHODS

207 AF patients and 160 healthy subjects were included in the case-control study. Blood samples were analyzed for the level of IL-11 by enzyme-linked immunosorbent assay (ELISA). Angiotensin II (Ang II)-treated fibrosis mouse models were generated, and expression of IL-11 mRNA and protein was detected by RT-qPCR and Western blot. IL-11 antagonist was used to evaluating atrial fibrosis-related markers.

RESULTS

The persistent atrial fibrillation patients (n = 76) had significantly larger left atrial size, higher serum levels of hypertrophic protein BNP, proinflammatory cytokine high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) compared to paroxysmal atrial fibrillation patients (n = 131), and healthy subjects (all p < 0.05). Pearson correlation analysis revealed significant positive correlation between serum IL-11 and cardiac fibrosis markers BNP (r = 0.394, p < 0.001), CTX-I (r = 0.418, p < 0.001), PICP (r = 0.306, p < 0.001), PIIINP (r = 0.335, p < 0.001), and TGF-β1 (r = 0.273, p < 0.001). In the fibrosis mouse model, Ang II infusion significantly upregulated IL-11 mRNA and protein expression in the left atrium of mice (p < 0.05), as well as staining intensity of Masson trichrome, the intensity of α-SMA, and it increased mRNA expression of collagen I and III in atrial tissue. IL-11 antagonist treatment significantly attenuated Masson trichrome, number of α-SMA-positive myofibroblasts in atrial tissue. Also, it significantly reduced the p-ERK1/2 in atrial tissue of mice infused with Ang II (p < 0.05).

CONCLUSIONS

IL-11 is upregulated in the serum of AF patients, and IL-11 inhibitor significantly inhibited Ang II-induced atrial fibrosis, a key pathological feature of AF. Therefore, IL-11 could be a potential therapeutic target for AF.

Angiotensin-receptor blocker losartan alleviates atrial fibrillation in rats by downregulating frizzled 8 and inhibiting the activation of WNT-5A pathway

Atrial fibrillation (AF) is a common arrhythmia. Angiotensin-receptor blocker (ARB) is related to AF treatment. This study explored the mechanism of ARB in AF. AF rat models were established by Ach-CaCl2 mixed solution injection. Rats were treated with ARB by gavage and injected with pcDNA3.1-based frizzled homolog 8 (FZD8) overexpression plasmids (oe-FZD8) through the tail vein. The 12-lead electrocardiogram was recorded by biological signal acquisition and processing system and AF duration was recorded, and atrial effective refractory period (AERP) was monitored by electrophysiology. Atrial fibrosis degree, FZD8 messenger RNA and protein levels, collagen I, collagen III, transforming growth factor β1 (TGF-β1), fibronectin, α smooth muscle actin (α-SMA), WBT-5B, and p-JNK1/2 levels, interleukin 1 β (IL-1β) and interleukin 6 (IL-6) levels were detected by Masson staining, reverse transcription quantitative polymerase chain reaction, western blot assay, immunohistochemistry, and enzyme-linked immunosorbent assay. ACh-CaCl2-induced AF rats showed a large area of fused necrosis, abnormal collagen fibre proliferation, high atrial fibrosis degree, and increased atrial fibrosis area in atrial interstitium, elevated collagen I, collagen III, TGF-β1, fibronectin, α-SMA, IL-1β, and IL-6 levels, whereas these trends were averted by ARB treatment. FZD8 was highly expressed in AF rat myocardium. ARB repressed FZD8 expression, prolonged AERP and reduced AF incidence. FZD8 overexpression annulled the effects of ARB on improving AF rat myocardial fibrosis. ARB inactivated the WNT-5A pathway by suppressing FZD8. ARB inactivated the WNT-5A pathway by silencing FZD8, therefore, alleviating AF rat atrial fibrosis.

Higher serum tissue inhibitor of metalloproteinase-1 predicts atrial fibrillation recurrence after radiofrequency catheter ablation

Background

Tissue inhibitor of metalloproteinase-1 (TIMP-1) levels is strongly associated with cardiac extracellular matrix accumulation and atrial fibrosis. Whether serum levels of TIMP-1 are associated with atrial fibrillation (AF) recurrence following radiofrequency catheter ablation (RFCA) remains unknown.

Materials and methods

Serum TIMP-1 levels of patients with AF before they underwent initial RFCA were measured using ELISA. Univariate and multivariate-adjusted Cox models were constructed to determine the relationship between TIMP-1 levels and AF recurrence. Multivariate logistic regression analyses were performed to determine predictors of AF recurrence.

Results

Of the 194 enrolled patients, 61 (31.4%) had AF recurrence within the median 30.0 months (interquartile range: 16.5–33.7 months) of follow-up. These patients had significantly higher baseline TIMP-1 levels than those without AF recurrence (129.8 ± 65.7 vs. 112.0 ± 51.0 ng/ml, P = 0.041). The same was true of high-sensitivity C-reactive protein (3.9 ± 6.0 vs. 1.9 ± 2.8 ng/ml, P = 0.001). When a TIMP-1 cutoff of 124.15 ng/ml was set, patients with TIMP-1 ≥ 124.15 ng/ml had a higher risk of recurrent AF than those with TIMP-1 < 124.15 ng/ml (HR, 1.961, 95% CI, 1.182–2. 253, P = 0.009). Multivariate Cox regression analysis revealed that high TIMP-1 was an independent risk factor for AF recurrence. Univariate Cox regression analysis found that substrate modification surgery does not affect AF recurrence (P = 0.553). Subgroup analysis revealed that female sex, age < 65 years, hypertension (HTN), body mass index (BMI) ≥ 24 kg/m², CHA2DS2-VASc score < 2, HAS-BLED score < 3, and EHRA score = 3 combined with high TIMP-1 level would perform well at predicting AF recurrence after RFCA.

Conclusion

Elevated preoperative TIMP-1 levels are related to a higher risk of AF recurrence and can independently predict AF recurrence following RFCA.

miR-29b ameliorates atrial fibrosis in rats with atrial fibrillation by targeting TGFβRΙ and inhibiting the activation of Smad-2/3 pathway

OBJECTIVE

Atrial fibrillation (AF) is a major cause of stroke with lifetime risks. microRNAs (miRNAs) are associated with AF attenuation, yet the mechanism remains unknown. This study investigated the functional mechanism of miR-29b in atrial fibrosis in AF.

METHODS

The AF rat model was established by a 7-day intravenous injection of Ach-CaCl₂ mixture. AF rats were injected with adeno-associated virus (AAv)-miR-29b and TGFβRΙ overexpression plasmid. AF duration was recorded by electrocardiogram. Atrial fibrosis was observed by Masson staining. Expressions of COL1A1, COL3A1, TGFβRΙ, TGFβΙ, miR-29b and Smad-2/3 pathway-related proteins in atrial tissues were detected by RT-qPCR and Western blot. Binding sites of miR-29b and TGFβRΙ were predicted and their target relationship was verified by dual-luciferase reporter assay.

RESULTS

miR-29b was poorly expressed and expressions of COL1A1, COL3A1, TGFβRΙ, and TGFβ1 were increased in atrial tissues of AF rats. miR-29b overexpression alleviated atrial fibrosis, reduced expressions of COL1A1, COL3A1, and TGFβ1, and shortened AF duration in AF rats. TGFβRΙ was highly expressed in atrial tissues of AF rats. miR-29b targeted TGFβRΙ. TGFβRΙ overexpression overcame the improving effect of miR-29b overexpression on AF. miR-29b overexpression decreased ratios of p-Smad-2/3 and Smad-2/3 and inhibited the Smad-2/3 pathway.

CONCLUSION

miR-29b might mitigate atrial fibrosis in AF rats by targeting TGFβRΙ and inhibiting the Smad-2/3 pathway.

The Blinding Period Following Ablation Therapy for Atrial Fibrillation: Proarrhythmic and Antiarrhythmic Pathophysiological Mechanisms

Atrial fibrillation (AF) causes heart failure, ischemic strokes, and poor quality of life. The number of patients with AF is estimated to increase to 18 million in Europe in 2050. Pharmacological therapy does not cure AF in all patients. Ablative pulmonary vein isolation is recommended for patients with drug-resistant symptomatic paroxysmal AF but is successful in only about 60%. In patients in whom ablative therapy is successful on the long term, recurrence of AF may occur in the first weeks to months after pulmonary vein ablation. The early recurrence (or delayed cure) of AF is not understood but forms the basis for the generally accepted 3-month blinding (or blanking) period after ablation therapy, which is not included in the evaluation of the eventual success rate of the procedures. The underlying pathophysiological processes responsible for early recurrence and the delayed cure are unknown. The implicit assumption of the blinding period is that the AF mechanism in this period is different from the ablation-targeted AF mechanism (ectopy from the pulmonary veins). In this review, we evaluate the temporary and long-lasting pro- and antiarrhythmic effects of each of the pathophysiological processes and interventions (necrosis, ischemia, oxidative stress, edema, inflammation, autonomic nervous activity, tissue repair, mechanical remodeling, and use of antiarrhythmic drugs) occurring in the blinding period that can modulate AF mechanisms. We propose that stretch-reducing ablation scar is a permanent antiarrhythmic mechanism that develops during the blinding period and is the reason for delayed cure.

Atrial fibrillation and cardiac fibrosis

The understanding of atrial fibrillation (AF) evolved from a sole rhythm disturbance towards the complex concept of a cardiomyopathy based on arrhythmia substrates. There is evidence that atrial fibrosis can be visualized using late gadolinium enhancement cardiac magnetic resonance imaging and that it is a powerful predictor for the outcome of AF interventions. However, a strategy of an individual and fibrosis guided management of AF looks promising but results from prospective multicentre trials are pending. This review gives an overview about the relationship between cardiac fibrosis and AF focusing on translational aspects, clinical observations, and fibrosis imaging to emphasize the concept of personalized paths in AF management taking into account the individual amount and distribution of fibrosis.

Atrial fibrosis underlying atrial fibrillation (Review)

Atrial fibrillation (AF) is one of the most common tachyarrhythmias observed in the clinic and is characterized by structural and electrical remodelling. Atrial fibrosis, an emblem of atrial structural remodelling, is a complex multifactorial and patient-specific process involved in the occurrence and maintenance of AF. Whilst there is already considerable knowledge regarding the association between AF and fibrosis, this process is extremely complex, involving intricate neurohumoral and cellular and molecular interactions, and it is not limited to the atrium. Current technological advances have made the non-invasive evaluation of fibrosis in the atria and ventricles possible, facilitating the selection of patient-specific ablation strategies and upstream treatment regimens. An improved understanding of the mechanisms and roles of fibrosis in the context of AF is of great clinical significance for the development of treatment strategies targeting the fibrous region. In the present review, a focus was placed on the atrial fibrosis underlying AF, outlining its role in the occurrence and perpetuation of AF, by reviewing recent evaluations and potential treatment strategies targeting areas of fibrosis, with the aim of providing a novel perspective on the management and prevention of AF.

How transforming growth factor contributes to atrial fibrillation?

Atrial fibrillation (AF) is the most common clinically significant arrhythmia. There are four fundamental pathophysiological mechanisms of AF including: electrical remodeling, structural remodeling, autonomic nervous system changes, and Ca2+ handling abnormalities. The transforming growth factor-β (TGF-β) superfamily are cytokines that have the ability to regulate numerous cell functions including proliferation, differentiation, apoptosis, epithelial-mesenchymal transition, and production of extracellular matrix. During the last decade numerous studies have demonstrated that TGF-β affects the architecture of the heart. TGF-β1 has been shown to be involved in the development and propagation of atrial fibrillation (AF). Investigators have studied TGF-β signaling in AF with the aim of discovering potential therapeutic agents. In this review we discuss the role of TGF-β in atrial fibrillation and specifically its role in atrial structural and electrical remodeling.

Imaging, biomarker and invasive assessment of diffuse left ventricular myocardial fibrosis in atrial fibrillation

BACKGROUND

Using cardiovascular magnetic resonance imaging (CMR), it is possible to detect diffuse fibrosis of the left ventricle (LV) in patients with atrial fibrillation (AF), which may be independently associated with recurrence of AF after ablation. By conducting CMR, clinical, electrophysiology and biomarker assessment we planned to investigate LV myocardial fibrosis in patients undergoing AF ablation.

METHODS

LV fibrosis was assessed by T1 mapping in 31 patients undergoing percutaneous ablation for AF. Galectin-3, coronary sinus type I collagen C terminal telopeptide (ICTP), and type III procollagen N terminal peptide were measured with ELISA. Comparison was made between groups above and below the median for LV extracellular volume fraction (ECV), followed by regression analysis.

RESULTS

On linear regression analysis LV ECV had significant associations with invasive left atrial pressure (Beta 0.49, P = 0.008) and coronary sinus ICTP (Beta 0.75, P < 0.001), which remained significant on multivariable regression.

CONCLUSION

LV fibrosis in patients with AF is associated with left atrial pressure and invasively measured levels of ICTP turnover biomarker.

Biomarkers Associated with Atrial Fibrosis and Remodeling

Atrial fibrillation is the most common rhythm disturbance encountered in clinical practice. Although often considered as solely arrhythmic in nature, current evidence has established that atrial myopathy constitutes both the substrate and the outcome of atrial fibrillation, thus initiating a vicious, self-perpetuating cycle. This myopathy is triggered by stress-induced (including pressure/volume overload, inflammation, oxidative stress) responses of atrial tissue, which in the long term become maladaptive, and combine elements of both structural, especially fibrosis, and electrical remodeling, with contemporary approaches yielding potentially useful biomarkers of these processes. Biomarker value becomes greater given the fact that they can both predict atrial fibrillation occurrence and treatment outcome. This mini-review will focus on the biomarkers of atrial remodeling (both electrical and structural) and fibrosis that have been validated in human studies, including biochemical, histological and imaging approaches.

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.

Can we predict tuberculosis cure? What tools are available?

Antibiotic treatment of tuberculosis takes ≥6 months, putting a major burden on patients and health systems in large parts of the world. Treatment beyond 2 months is needed to prevent tuberculosis relapse by clearing remaining, drug-tolerant Mycobacterium tuberculosis bacilli. However, the majority of patients treated for only 2-3 months will cure without relapse and do not need prolonged treatment. Assays that can identify these patients at an early stage of treatment may significantly help reduce the treatment burden, while a test to identify those patients who will fail treatment may help target host-directed therapies.In this review we summarise the state of the art with regard to discovery of biomarkers that predict relapse-free cure for pulmonary tuberculosis. Positron emission tomography/computed tomography scanning to measure pulmonary inflammation enhances our understanding of "cure". Several microbiological and immunological markers seem promising; however, they still need a formal validation. In parallel, new research strategies are needed to generate reliable tests.

Changes in Left Atrial Transport Function in Patients Who Maintained Sinus Rhythm After Successful Radiofrequency Catheter Ablation for Atrial Fibrillation: A 1-Year Follow-Up Multislice Computed Tomography Study

BACKGROUND

Functional remodeling of left atrium (LA) after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been fully elucidated. This study aimed to determine the impact of RFCA on LA transport function in patients who maintained sinus rhythm (SR) after AF ablation.

METHODS AND RESULTS

A total of 96 patients (paroxysmal AF [PAF] = 52) who maintained SR during 1 year after AF ablation were enrolled. Multislice computed tomography was performed to determine LA volume (LAV) and LA emptying fraction (LAEF) at pre-RFCA and 1-year post-RFCA. Creatine kinase-MB (CK-MB) and troponin-T levels were analyzed 1-day post-RFCA. At 1-year post-RFCA, mean LAV and LAEF decreased in overall patients. Based on LAEF change (ΔLAEF) cutoff of 5.0%, LAEF reduced in 41 patients (worsened group) and improved or showed no change in 55 patients (preserved group). Compared with preserved group, worsened group had a higher proportion of PAF, higher levels of CK-MB and troponin-T, and additional LA ablation. ΔLAEF was inversely correlated with CK-MB and troponin-T levels. Subgroup analysis showed that LAEF significantly decreased in PAF patients who underwent additional LA ablation. Multivariate analysis revealed that high baseline LAEF and additional LA ablation were independent predictors for worsened LAEF.

CONCLUSIONS

Although SR was maintained for 1 year after AF ablation, LAEF as well as LAV decreased. The extent of LAEF deterioration was significantly associated with the amount of iatrogenic myocardial damage. Our data indicate that extensive atrial ablation may lead to LA functional deterioration, especially in patients with PAF.

The serum matrix metalloproteinase-9 level is an independent predictor of recurrence after ablation of persistent atrial fibrillation

OBJECTIVES

This study investigated whether the serum matrix metalloproteinase-9 level is an independent predictor of recurrence after catheter ablation for persistent atrial fibrillation.

METHODS

Fifty-eight consecutive patients with persistent atrial fibrillation were enrolled and underwent catheter ablation. The serum matrix metalloproteinase-9 level was detected before ablation and its relationship with recurrent arrhythmia was analyzed at the end of the follow-up.

RESULTS

After a mean follow-up of 12.1±7.2 months, 21 (36.2%) patients had a recurrence of their arrhythmia after catheter ablation. At baseline, the matrix metalloproteinase-9 level was higher in the patients with recurrence than in the non-recurrent group (305.77±88.90 vs 234.41±93.36 ng/ml, respectively, p=0.006). A multivariate analysis showed that the matrix metalloproteinase-9 level was an independent predictor of arrhythmia recurrence, as was a history of atrial fibrillation and the diameter of the left atrium.

CONCLUSION

The serum matrix metalloproteinase-9 level is an independent predictor of recurrent arrhythmia after catheter ablation in patients with persistent atrial fibrillation.

Cardiac Fibrosis in Patients With Atrial Fibrillation: Mechanisms and Clinical Implications

Atrial fibrillation (AF) is associated with structural, electrical, and contractile remodeling of the atria. Development and progression of atrial fibrosis is the hallmark of structural remodeling in AF and is considered the substrate for AF perpetuation. In contrast, experimental and clinical data on the effect of ventricular fibrotic processes in the pathogenesis of AF and its complications are controversial. Ventricular fibrosis seems to contribute to abnormalities in cardiac relaxation and contractility and to the development of heart failure, a common finding in AF. Given that AF and heart failure frequently coexist and that both conditions affect patient prognosis, a better understanding of the mutual effect of fibrosis in AF and heart failure is of particular interest. In this review paper, we provide an overview of the general mechanisms of cardiac fibrosis in AF, differences between fibrotic processes in atria and ventricles, and the clinical and prognostic significance of cardiac fibrosis in AF.

The effect of ablation for paroxysmal atrial fibrillation on left atrial volume and function: a one-year follow-up study

PURPOSE

The effect of radiofrequency catheter ablation (RFCA) on left atrial (LA) volume and function in patients with paroxysmal atrial fibrillation (PAF) has not been extensively studied. The aim of this study was to evaluate the long-term impact of RFCA on LA volume and function in patients with PAF.

MATERIALS AND METHODS

A total of 90 patients with drug-refractory PAF who had sinus rhythm on the initial echocardiogram were examined at baseline, 3 months and 1 year after ablation. We measured LA volume index, LA ejection fraction (LAEF; maximal-minimal LA volume/maximal LA volume), and LA active emptying fraction (LAAEF; mid-diastolic-minimal LA volume/mid-diastolic LA volume).

RESULTS

After 12±1 months, 78 patients returned, and 61 patients (78%) had sinus rhythm. After 3 months, the LA maximal volume indices decreased (from 33±13 to 28±12 mL/m²; p<0.001). But, LAEF and LAAEF also decreased (from 48±13 to 39±12; p<0.001, from 27±13 to 19±11; p<0.001). After 1 year, LA volumes, LAEF, and LAAEF remained similar at 3 months. In patients without atrial fibrillation (AF) recurrence, LAEF and LAAEF decreased after 3 months (from 50±12 to 40±11; p<0.001, from 29±13 to 22±11; p<0.001) and did not change after 1 year. However, in patients with AF recurrence, those who did not have decreased levels after 3 months had significantly decreased after 1 year (from 43±14 to 34±11; p=0.026, from 22±12 to 15±10; p=0.012).

CONCLUSION

Successful RFCA of PAF decreased LA volume and function at 3 months. At one year, LA volume and function was remained unchanged in successfully ablated patients whereas LA function in patients with AF recurrence worsened.

Rhythm outcomes after catheter ablation of atrial fibrillation. Clinical implication of biomarkers

Atrial fibrillation (AF) occurs as the result of numerous complex physiological processes in the atria leading to AF promotion and maintenance. Improved diagnostic techniques have identified various biomarkers which may play an important role in the prediction of AF related outcomes (cardio- and cerebrovascular events, as well as mortality and rhythm outcomes). Biomarkers refer to 'biological markers' and biomarkers in blood, urine as well as imaging marker (eg, dimensions (left atrial diameter and volume), anatomical features (left appendage and pulmonary vein anatomy), and physiological pattern (LAA flow velocity)) may play important role(s) as clinically important indices in relation to outcomes after different therapeutic strategies. However, the main domain in the biomarker field has focused on blood-based biomarkers, which are widely used to predict therapeutic success regarding underlying pathophysiological mechanism, such as inflammation, fibrosis, endothelial damage. This review provides an update of the role of clinically relevant biomarkers in AF, with particular focus on AF rhythm outcomes.

Serum sRANKL/OPG predict recurrence after radiofrequency catheter ablation of lone atrial fibrillation

BACKGROUND

Radiofrequency catheter ablation (RFCA) is a widely accepted strategy for eliminating atrial fibrillation (AF). A considerable recurrence rate has partly been ascribed to atrial remodeling. Osteoprotegerin (OPG)/receptor activator of nuclear factor-κB (RANK)/RANK ligand (RANKL) axis may contribute to the development and progression of AF by regulating atrial structural remodeling. This study aimed to determine the relationship between serum soluble RANKL (sRANKL)/OPG and the risk of recurrent arrhythmia after ablation of lone AF.

METHODS

We enrolled 527 lone AF patients undergoing first-time RFCA with complete follow-up data. Pre-ablation venous blood samples were obtained for measurement of serum sRANKL and OPG.

RESULTS

During the follow-up period of 15 (3-64)months, AF recurred in 187 patients (35.5%). Recurrence was associated with an elevation of serum sRANKL level and sRANKL/OPG ratio. In multivariate survival regression, persistent AF, AF duration, left atrial diameter, amiodarone after ablation, particularly serum sRANKL level and sRANKL/OPG ratio independently predicted AF recurrence. According to ROC curve analysis, the best diagnostic values of serum sRANKL level and sRANKL/OPG ratio for predicting recurrence were 4.89 pmol/l and 0.76, respectively.

CONCLUSIONS

Baseline serum high sRANKL level and sRANKL/OPG ratio are associated with AF recurrence after primary ablation procedure in lone AF patients, and may be used in the prediction of AF recurrence in these patients.

Markers of oxidative stress after ablation of atrial fibrillation are associated with inflammation, delivered radiofrequency energy and early recurrence of atrial fibrillation

BACKGROUND

The role of oxidative stress after radiofrequency ablation of atrial fibrillation (AF) has not yet been well characterized. We sought to evaluate the time course of biomarkers of oxidative stress and inflammation after AF ablation and their association with clinical variables.

METHODS

Thirty consecutive patients (57.9 ± 1.7 years, 63% males) with paroxysmal AF underwent pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Biomarkers were determined in blood samples before ablation and 6 h, 1, 2, 7, 30, 90 and 180 days post-ablation.

RESULTS

The pro-oxidant enzyme myeloperoxidase and oxidized low-density lipoprotein reflecting oxidant damage of lipoproteins increased 2.9 ± 0.2-fold and 1.2 ± 0.1-fold, respectively, and were significantly up-regulated until day 2 post-ablation. The anti-oxidant enzyme copper/zinc superoxide dismutase did not change significantly. Inflammatory markers significantly increased (high-sensitivity C-reactive protein (hs-CRP): 41 ± 8-fold; interleukin-6: 4.4 ± 0.7-fold) for 7 and 2 days, respectively. The increase of myeloperoxidase and hs-CRP was interrelated and both predicted early recurrence of AF within the first post-ablation week (both p < 0.05). The increase of both markers was associated with the amount of delivered radiofrequency energy (p < 0.05). The up-regulation of hs-CRP correlated with troponin T (p = 0.008), while myeloperoxidase and troponin T were borderline associated (p = 0.054). However, the oxidative and inflammatory responses did not predict long-term ablation outcome (p > 0.05).

CONCLUSIONS

Markers of oxidative stress showed a significant up-regulation during the first 2 days after AF ablation. Their up-regulation was linked to inflammation, delivered radiofrequency energy, and early recurrence of AF, but did not predict long-term ablation outcome.