Analysis of pravastatin to prevent recurrence of atrial fibrillation after electrical cardioversion

Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications

Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.

Overview of Cardiac Arrhythmias and Treatment Strategies

Maintenance of normal cardiac rhythm requires coordinated activity of ion channels and transporters that allow well-ordered propagation of electrical impulses across the myocardium. Disruptions in this orderly process provoke cardiac arrhythmias that may be lethal in some patients. Risk of common acquired arrhythmias is increased markedly when structural heart disease caused by myocardial infarction (due to fibrotic scar formation) or left ventricular dysfunction is present. Genetic polymorphisms influence structure or excitability of the myocardial substrate, which increases vulnerability or risk of arrhythmias in patients. Similarly, genetic polymorphisms of drug-metabolizing enzymes give rise to distinct subgroups within the population that affect specific drug biotransformation reactions. Nonetheless, identification of triggers involved in initiation or maintenance of cardiac arrhythmias remains a major challenge. Herein, we provide an overview of knowledge regarding physiopathology of inherited and acquired cardiac arrhythmias along with a summary of treatments (pharmacologic or non-pharmacologic) used to limit their effect on morbidity and potential mortality. Improved understanding of molecular and cellular aspects of arrhythmogenesis and more epidemiologic studies (for a more accurate portrait of incidence and prevalence) are crucial for development of novel treatments and for management of cardiac arrhythmias and their consequences in patients, as their incidence is increasing worldwide.

Upstream Therapy for Atrial Fibrillation Prevention: The Role of Sacubitril/Valsartan

The therapy or prevention of atrial fibrillation (AF) is defined as upstream therapy when conducted with the use of drugs, e.g., angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor antagonists, statins, and omega-3 fatty acids, not included in the classes of antiarrhythmic drugs recognized by the Vaughan Williams classification. In our review, we illustrate the rational bases of upstream AF therapy, which encompasses drugs having the property to reduce hemodynamic congestion and cardiac overload, as in the case of ACEIs or angiotensin receptor blockers, as well as drugs able to prevent atrial fibrosis or reduce oxidative stress, such as statins or omega-3 fatty acids, respectively. In this review, randomized controlled trials (RCTs) conducted with the abovementioned drugs are examined. Really, these RCTs have generated mixed results. In the context of the prevention and therapy of AF, our experience is then presented, relating to a patient with heart failure and reduced left ventricular ejection fraction, with a history of relapsing episodes of paroxysmal AF. In this patient, administration of sacubitril/valsartan at appropriate doses allowed recovery of the sinus rhythm. Therefore this case testifies how the upstream therapy of AF might have good results when conducted with sacubitril/valsartan. Thus, RCTs with adequate statistical power are warranted in order to confirm the preliminary encouraging result of our case report, and validate a useful role of sacubitril/valsartan as an upstream therapy of AF.

The Pleiotropic Effects of Statins - From Coronary Artery Disease and Stroke to Atrial Fibrillation and Ventricular Tachyarrhythmia

Statins, 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors, have been used for decades for the prevention of coronary artery disease and stroke. They act primarily by lowering serum cholesterol through the inhibition of cholesterol synthesis in the liver, which results in the upregulation of low-density lipoprotein receptors in the liver. This results in the removal of low-density lipoproteincholesterol. Studies have suggested that statins may demonstrate additional effects that are independent of their effects on low-density lipoprotein-cholesterol. These have been termed "pleiotropic" effects. Pleiotropic effects may be due to the inhibition of isoprenoid intermediates by statins. Isoprenoid inhibition has effects on the small guanosine triphosphate binding proteins Rac and Rho which in turn effects nicotinamide adenine dinucleotide phosphate oxidases. Therefore, there are changes in endothelial nitric oxide synthase expression, atherosclerotic plaque stability, pro-inflammatory cytokines and reactive oxygen species production, platelet reactivity, and cardiac fibrosis and hypetrophy development. Recently, statins have been compared to the ezetimibe and the recently published outcomes data on the proprotein convertase subtilisin kexin type 9 inhibitors has allowed for a reexamination of statin pleiotropy. As a result of these diverse effects, it has been suggested that statins also have anti-arrhythmic effects. This review focuses on the mechanisms of statin pleiotropy and discusses evidence from the statin clinical trials as well as examining the possible anti-arrhythmic effects atrial fibrillation and ventricular tachyarrhythmias.

Redox State in Atrial Fibrillation Pathogenesis and Relevant Therapeutic Approaches

BACKGROUND

Myocardial redox state is a critical determinant of atrial biology, regulating cardiomyocyte apoptosis, ion channel function, and cardiac hypertrophy/fibrosis and function. Nevertheless, it remains unclear whether the targeting of atrial redox state is a rational therapeutic strategy for atrial fibrillation prevention.

OBJECTIVE

To review the role of atrial redox state and anti-oxidant therapies in atrial fibrillation.

METHOD

Published literature in Medline was searched for experimental and clinical evidence linking myocardial redox state with atrial fibrillation pathogenesis as well as studies looking into the role of redoxtargeting therapies in the prevention of atrial fibrillation.

RESULTS

Data from animal models have shown that altered myocardial nitroso-redox balance and NADPH oxidases activity are causally involved in the pathogenesis of atrial fibrillation. Similarly experimental animal data supports that increased reactive oxygen / nitrogen species formation in the atrial tissue is associated with altered electrophysiological properties of atrial myocytes and electrical remodeling, favoring atrial fibrillation development. In humans, randomized clinical studies using redox-related therapeutic approaches (e.g. statins or antioxidant agents) have not documented any benefits in the prevention of atrial fibrillation development (mainly post-operative atrial fibrillation risk).

CONCLUSION

Despite strong experimental and translational data supporting the role of atrial redox state in atrial fibrillation pathogenesis, such mechanistic evidence has not been translated to clinical benefits in atrial fibrillation risk in randomized clinical studies using redox-related therapies.

Use of statins and recurrence of atrial fibrillation after catheter ablation or electrical cardioversion

Statins have important pleiotropic effects and have been shown to reduce vascular inflammation. Some evidence suggests that statins may have a role in the primary prevention of atrial fibrillation (AF), whereas little is know on the role of statins in patients with existing AF. We performed a meta-analysis of the literature to assess the effect of statins on the recurrence of AF after electrical cardioversion or ablation. MEDLINE and EMBASE databases were searched up to January 2010. Relative risks (RR) and 95% confidence intervals (CIs) were then calculated and pooled using a random-effects model. Statistical heterogeneity was evaluated through the use of I2 statistics. Sixteen studies were included in our systematic review. Statins did not reduce the risk of AF recurrence after ablation (four studies including 750 patients; RR, 1.04; 95% CI, 0.85–1.28, p=0.71; I2 = 34%). Conversely, the use of statins was associated with a significantly reduced risk of AF recurrence after electrical cardioversion (12 studies including 1790 patients; RR, 0.78; 95% CI, 0.67–0.90, p=0.0003; I2 = 34%). This reduction was not statistically significant when the analysis was restricted to randomised controlled trials (RCTs) only (five studies, 458 patients, RR, 0.76; 95% CI, 0.48–1.20). In conclusion, statins may lower the risk of AF recurrence after electrical cardioversion, but not ablation. However, this finding should be considered with caution, and larger RCTs are warranted to confirm our preliminary results.

Cardiology: Post-Cardiothoracic Surgery Atrial Fibrillation: A Review of Preventive Strategies

Objective:

To review the available literature addressing preventive strategies of post-cardiothoracic surgery atrial fibrillation (post-CTS atrial fibrillation).

Data Sources:

Pertinent articles related to the etiology, risk factors, and preventive strategies were identified through a MEDLINE search (1966–March 2007) using the MeSH terms atrial fibrillation, cardiothoracic surgery, cardiac surgery, etiology, neurohormonal, sympathetic, volume, fluid, inflammation, risk factors, operative, pacing, β-adrenergic blockers, amiodarone, sotalol, calcium-channel blockers, magnesium, HMG-CoA reductase inhibitors, statins, fatty acids, PUFA, steroids, and nonsteroidal antiinflammatory drugs.

Study Selection and Data Extraction:

Articles evaluated were limited to human studies, published in the English language, with a Jadad score greater than 3. References of identified articles were reviewed for additional pertinent articles.

Data Synthesis:

Post-CTS atrial fibrillation most commonly occurs on the second or third postoperative day, with an incidence of 20–50%. Etiology theories include neurohormonal activation, volume overload, and inflammation. Studies examining nonpharmacologic therapies have shown that maintenance of the anterior epicardial fat pad is not a viable prophylactic strategy. Biatrial cardiac pacing, especially in combination with amiodarone, is a viable preventive option. Withdrawal of preoperative β-blockers places patients at higher risk for atrial fibrillation; these drugs should be continued postoperatively. Evidence exists supporting the use of amiodarone, sotalol, and magnesium in addition to β-blockers. Since most of these strategies work by attenuating neurohormonal activation, adverse events, including hypotension and bradycardia, are of concern. Adding agents with antiinflammatory properties, including hydroxymethylglutaryl coenzyme A reductase inhibitors or corticosteroids, may prove to be of benefit. Additional studies using novel therapies are needed in addition to established preventive strategies.

Conclusions:

Available evidence supports the continuation of preoperative β-blockers, as well as prophylactic amiodarone, sotalol, and magnesium. Other novel therapies, mostly targeting inflammation, are under investigation and may provide additional strategies.

Atrial Electromechanical Properties in Inflammatory Bowel Disease

BACKGROUND

There is much evidence linking inflammation to the initiation and continuation of atrial fibrillation (AF). Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic systemic inflammatory disorders. Atrial electromechanical delay (EMD) has been known as an early marker of AF. The objectives of this study were to evaluate the atrial electromechanical properties in patients with IBD.

METHODS

Fifty-two patients with IBD and 26 healthy controls were recruited in the study. Twenty-five of patients with IBD were on active period, and the remaining 27 were on remission period. Atrial electromechanical properties were measured by using transthoracic echocardiography and tissue Doppler imaging and simultaneous surface ECG recording. Interatrial EMD, left intraatrial EMD, and right intraatrial EMD were calculated.

RESULTS

Patients on activation with IBD had significantly prolonged left and right intraatrial EMDs and interatrial EMD compared to patients on remission (P = 0.048, P = 0.036, P < 0.001, respectively) and healthy controls (P < 0.001, for all comparisons). Left and right intraatrial EMDs and interatrial EMD were also found to be higher when patients on remission with IBD compared with healthy controls. No statistical difference was observed between UC and CD in terms of inter- and intraatrial EMDs.

CONCLUSIONS

Atrial electromechanical conduction is prolonged in IBD, and exposure to chronic inflammation may lead to structural and electrophysiological changes in the atrial tissue that causes slow conduction. Measurement of atrial EMD parameters might be used to predict the risk for the development of AF in patients with IBD.

Atrial fibrillation coincides with the advanced glycation end product N(ε)-(carboxymethyl)lysine in the atrium

Presence of advanced glycation end products (AGEs) in the heart induces a proinflammatory phenotype. However, the presence of AGEs within atrial tissue of atrial fibrillation (AF) patients is unknown and was analyzed here. Left atrial appendage tissue from 33 AF patients and 9 controls was analyzed for the presence of the major AGEs N(ε)-(carboxymethyl)lysine (CML), VCAM-1, neutrophilic granulocytes, lymphocytes, and macrophages in both the fat tissue and myocardium separately. The total amount of fibrosis was also analyzed. Presence of CML was significantly higher in blood vessels of the left atrial appendage in AF patients as compared to controls, independent of diabetes mellitus. In AF patients, VCAM-1 expression in blood vessels and the numbers of infiltrated neutrophilic granulocytes, lymphocytes, and macrophages significantly increased compared to controls, and were highest in the fat tissue; there was no significant difference in fibrosis compared to controls. Interestingly, total amount of CML and fibrosis in AF and control patients correlated positively. Finally, there was no difference between AF patients based on AF type or surgical indication in the presence of CML, VCAM-1 expression, inflammatory cells, and fibrosis. Our results indicate that in AF the intramyocardial blood vessels of the left atrial appendage have an increased CML presence and proinflammatory status coinciding with a local increase in the number of inflammatory cells.

Atrial electromechanical delay is impaired in patients with psoriasis

OBJECTIVE

In this study, we aimed to investigate atrial electromechanical delay (EMD) in patients with psoriasis.

SUBJECTS AND METHODS

A total of 43 patients with psoriasis (26 mild-moderate, 17 severe) and 17 healthy control subjects were enrolled. Patients with psoriasis were divided into two groups: the mild-moderate group and the severe group according to their psoriasis area severity index (PASI) scores. Atrial EMD was measured from the lateral mitral annulus and called 'PA lateral', from the septal mitral annulus, called 'PA septal', and from the right ventricle tricuspid annulus, called 'PA tricuspid'. Atrial EMD was defined as the time interval from the onset of atrial electrical activity (P wave on surface ECG) to the beginning of mechanical atrial contraction (late diastolic A wave). All three groups were compared with each other, and correlation analysis was performed to investigate the relationship between the PASI score and interatrial EMD.

RESULTS

PA lateral was significantly higher in both the mild-moderate psoriasis group and the severe psoriasis group compared to controls (69 ± 12 and 78 ± 13 vs. 60 ± 6 ms; p = 0.001). Also, PA septal (63 ± 11 vs. 53 ± 6 ms; p = 0.005, post hoc analysis) and PA tricuspid (49 ± 7 vs. 41 ± 5 ms; p = 0.009, post hoc analysis) were significantly higher in the severe psoriasis group than in the control group. Correlation analysis revealed that the PASI score was well correlated with PA lateral (r = 0.520, p < 0.001), PA septum (r = 0.460, p = 0.002), interatrial EMD (r = 0.371, p = 0.014) and intra-atrial EMD (r = 0.393, p = 0.009).

CONCLUSION

Atrial EMD was prolonged in patients with psoriasis. The measurement of atrial EMD might be used to determine the risk of development of AF in patients with psoriasis.

Statin therapy decreased the recurrence frequency of atrial fibrillation after electrical cardioversion: a meta-analysis

Background

It is unclear whether statin agents provide clinical benefit in preventing the relapse of atrial fibrillation (AF) after electrical cardioversion (EC). The purpose of this study was to assess the effect of statin agents on the recurrence of AF after EC by conducting a meta-analysis of randomized controlled trials (RCTs).

Material/Methods

We conducted a systematic literature search of Medline, EMBASE, ISI Web of Science, and Cochrane databases. RCTs comparing clinical endpoint of the recurrence of AF associated with statin administration vs. no statin treatment (placebo or conventional medical therapy) in patients with AF after EC were eligible. Combined results are presented as risk ratios (RRs) with 95% confidence intervals (CIs).

Results

A total of 5 trials with 524 patients were available for analysis. The pooling analysis showed that statin agents significantly reduced the recurrence of AF after EC compared with no statin treatment (RR=0.76, 95% CI 0.63–0.92; p=0.004; I²=44%). The beneficial effect was shown both in AF subjects receiving atorvastatin or rosuvastatin treatment (atorvastatin 80 mg: RR=0.82, p=0.05; atorvastatin 10 mg: RR=0.27, p=0.03; rosuvastatin: RR=0.38, p=0.04) and in younger patients (<65 years; RR=0.58, p=0.0005). Furthermore, the benefit of statin agents on preventing AF recurrence after EC was demonstrated within 3-month follow-up (p=0.03), and the clinical benefit seemed likely to remain until no less than 12 months after EC (p=0.05).

Conclusions

Based on the currently available data, administration of statin agents, especially atorvastatin or rosuvastatin, is beneficial in lowering the frequency of AF recurrence after EC.

Transient post-operative atrial fibrillation predicts short and long term adverse events following CABG

OBJECTIVE

To assess the relationship between the development of transient post-operative atrial fibrillation (TPOAF) following coronary artery bypass graft (CABG) surgery and risk of long-term mortality.

BACKGROUND

Atrial fibrillation (AF) following CABG is common and associated with increased morbidity and mortality in the perioperative period. However the impact of TPOAF and its management on long-term morbidity and mortality in patients undergoing first time, isolated CABG surgery remains unclear.

METHODS

The Cleveland Clinic Cardiovascular Information Registry was used to identify 5,205 consecutive patients who underwent CABG between January 1993 and December 2005. Patients with TPOAF (n=1,490) were compared to those without post-operative AF (n=3,645) for the endpoints of death, myocardial infarction (MI), or stroke at 1 year.

RESULTS

Overall rates of 1-year mortality, MI and stroke were 3.7%, 0.8%, and 2.6%, respectively. Patients with TPOAF had an increased risk of death at 1 year as compared to patients without POAF (6.4% vs. 2.7%; P<0.001), but there was not an increased risk of stroke or MI. Multivariate analysis identified TPOAF as an independent predictor of death at 1 year (HR 1.89, 95% CI, 1.42-2.53; P<0.001). After propensity matching, patients who developed TPOAF experienced a significantly increased risk of death compared with those without TPOAF (HR 1.96, 95% CI, 1.34-2.86; P<0.001).

CONCLUSIONS

In patients undergoing first time, isolated CABG, the presence of TPOAF identifies a subgroup of patients at increased risk for all-cause mortality. Future prospective studies to determine potential beneficial interventions in this large population are warranted.

Attenuation of acetylcholine activated potassium current (I KACh) by simvastatin, not pravastatin in mouse atrial cardiomyocyte: possible atrial fibrillation preventing effects of statin

Statins, 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors, are associated with the prevention of atrial fibrillation (AF) by pleiotropic effects. Recent clinical trial studies have demonstrated conflicting results on anti-arrhythmia between lipophilic and hydrophilic statins. However, the underlying mechanisms responsible for anti-arrhythmogenic effects of statins are largely unexplored. In this study, we evaluated the different roles of lipophilic and hydrophilic statins (simvastatin and pravastatin, respectively) in acetylcholine (100 µM)-activated K⁺ current (I_KACh, recorded by nystatin-perforated whole cell patch clamp technique) which are important for AF initiation and maintenance in mouse atrial cardiomyocytes. Our results showed that simvastatin (1–10 µM) inhibited both peak and quasi-steady-state I_KACh in a dose-dependent manner. In contrast, pravastatin (10 µM) had no effect on I_KACh. Supplementation of substrates for the synthesis of cholesterol (mevalonate, geranylgeranyl pyrophosphate or farnesyl pyrophosphate) did not reverse the effect of simvastatin on I_KACh, suggesting a cholesterol-independent effect on I_KACh. Furthermore, supplementation of phosphatidylinositol 4,5-bisphosphate, extracellular perfusion of phospholipase C inhibitor or a protein kinase C (PKC) inhibitor had no effect on the inhibitory activity of simvastatin on I_KACh. Simvastatin also inhibits adenosine activated I_KACh, however, simvastatin does not inhibit I_KACh after activated by intracellular loading of GTP gamma S. Importantly, shortening of the action potential duration by acetylcholine was restored by simvastatin but not by pravastatin. Together, these findings demonstrate that lipophilic statins but not hydrophilic statins attenuate I_KACh in atrial cardiomyocytes via a mechanism that is independent of cholesterol synthesis or PKC pathway, but may be via the blockade of acetylcholine binding site. Our results may provide important background information for the use of statins in patients with AF.

The efficacy and tolerability of commonly used agents to prevent recurrence of atrial fibrillation after successful cardioversion

A number of therapeutic strategies exist for the restoration and maintenance of sinus rhythm in patients presenting with atrial fibrillation. The acute success rate with electrical cardioversion is high. However, many patients relapse into atrial fibrillation. A major challenge faced by those who care for patients with atrial fibrillation is the long-term maintenance of sinus rhythm whilst avoiding treatment-related adverse effects. This review examines the efficacy and tolerability of conventional anti-arrhythmic drugs for the secondary prevention of atrial fibrillation in the post-cardioversion period.

Impact of duration and dosage of statin treatment and epicardial fat thickness on the recurrence of atrial fibrillation after electrical cardioversion

The purpose of this study was to investigate the time-dependent effect of statin treatment and echocardiographic epicardial fat thickness (EFT) on the maintenance of sinus rhythm (SR) in atrial fibrillation (AF) patients after electrical cardioversion (EC). One hundred sixty-three AF patients without previous statin treatment who underwent EC were consecutively enrolled. The maintenance rate of SR after EC (1, 3, 6, and 12 months) as documented by electrocardiogram and EFT were compared between patients with statin treatment (statin group, n = 63) and those without (no statin group, n = 100). There was no significant difference in the maintenance rate of SR between the groups soon after EC (statin group; 85.7 % vs. no statin; 84.8%, p = 0.535), after 1 month (71.0 vs. 59.1%, p = 0.091), and after 3 months (63.2 vs. 50.0%, p = 0.086). However, the maintenance rate of SR was significantly higher in the statin group compared to no statin group (61.8 vs. 42.9%, p = 0.024) after 6 months, and this significant difference persisted up to 12 months of follow up (60.1 vs. 36.4%, p = 0.001). Patients with recurrence showed higher baseline EFT (7.4 ± 2.7 vs. 8.5 ± 3.0 mm, p = 0.014). Multivariate linear regression analysis indicated that EFT, left atrial diameter, high-density lipoprotein cholesterol, statin treatment, and dose were the significant contributors to the maintenance of SR for all periods after EC. Statin treatment and low EFT were associated with a higher maintenance rate of SR in AF patients after EC. Significant benefit of statin was realized 6 months after EC, and this benefit was shown to be maintained over time.

Rac1-mediated effects of HMG-CoA reductase inhibitors (statins) in cardiovascular disease

SIGNIFICANCE

HMG-CoA reductase inhibitors (statins) lower serum cholesterol concentrations and are beneficial in the primary and secondary prevention of coronary heart disease. The positive clinical effects have only partially been reproduced with other lipid-lowering interventions suggesting potential statin effects in addition to cholesterol lowering. In experimental models, direct beneficial cardiovascular effects that are mediated by the inhibition of isoprenoids have been documented, which serve as lipid attachments for intracellular signaling molecules such as small Rho guanosine triphosphate-binding proteins, whose membrane localization and function are dependent on isoprenylation.

RECENT ADVANCES

Rac1 GTPase is an established master regulator of cell motility through the cortical actin reorganization and of reactive oxygen species generation through the regulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity.

CRITICAL ISSUES

Observations in cells, animals, and humans have implicated the activation of Rac1 GTPase as a key component of cardiovascular pathologies, including the endothelial dysfunction, cardiac hypertrophy and fibrosis, atrial fibrillation, stroke, hypertension, and chronic kidney disease. However, the underlying signal transduction remains incompletely understood.

FUTURE DIRECTIONS

Based on the recent advance made in Rac1 research in the cardiovascular system by using mouse models with transgenic overexpression of activated Rac1 or conditional knockout, as well as Rac1-specific small molecule inhibitor NSC 23766, the improved understanding of the Rac1-mediated effects statins may help to identify novel therapeutic targets and strategies.

Atrial fibrillation: inflammation in disguise?

Atrial fibrillation is highly prevalent, and affected patients are at an increased risk of a number of complications, including heart failure and thrombo-embolism. Over the past years, there has been increasing interest in the role of inflammatory processes in atrial fibrillation, from the first occurrence of the arrhythmia to dreaded complications such as strokes or peripheral emboli. As the standard drug combination which aims at rate control and anticoagulation only offers partial protection against complications, newer agents are needed to optimize treatment. In this paper, we review recent knowledge regarding the impact of inflammation on the occurrence, recurrence, perpetuation and complications of the arrhythmia, as well as the role of anti-inflammatory therapies in the treatment for the disease.

The risk of atrial fibrillation in patients with rheumatoid arthritis

BACKGROUND

Prior research suggests an important role of systemic inflammation in pathogenesis of atrial fibrillation (AF). It is well known that rheumatoid arthritis (RA), a chronic, systemic inflammatory disorder, increases the risk of cardiovascular disease (CVD), but little evidence exists whether the risk of AF is increased in RA.

METHODS

Using data from a large US commercial insurance plan, we examined the incidence rate (IR) of hospitalisation for AF in patients with RA compared with non-RA. RA patients were identified with ≥2 separate visits coded for RA and ≥1 disease-modifying antirheumatic drug dispensing. The IR of AF in RA patients was also compared with those with osteoarthritis, a chronic non-inflammatory condition.

RESULTS

There were 20 852 RA and 104 260 non-RA patients, matched on age, sex and index date. The mean follow-up was 2 years. The IR per 1000 person-years of AF was 4.0 (95% CI 3.4 to 4.7) in RA and 2.8 (95% CI 2.6 to 3.0) in non-RA patients. The IR ratio for AF was 1.4 (95% CI 1.2 to 1.7) in RA compared with non-RA patients. In a multivariable Cox model adjusting for a number of risk factors such as diabetes, CVD, medications and healthcare utilisation, the risk of AF was no longer increased in RA (HR 1.1, 95% CI 0.9 to 1.4) compared with non-RA patients. There was also no difference in the AF risk between RA and osteoarthritis patients.

CONCLUSIONS

Our results show no increased risk of AF associated with RA, after adjusting for various comorbidities, medications and healthcare use.

Angiotensin receptor blockers and statins could alleviate atrial fibrosis via regulating platelet-derived growth factor/Rac1/nuclear factor-kappa B Axis

AIMS

To investigate whether the administration of renin-angiotensin system (RAS) inhibitors and statins could alleviate atrial fibrosis via platelet-derived growth factor (PDGF)/Rac1 /nuclear factor-kappa B (NF-κB) axis.

METHODS AND RESULTS

In human left atrium, the degree of atrial fibrosis, as well as the expression levels of PDGF, Rac1 and NF-κB increased 1.5 to 2.9 folds in patients with atrial fibrillation compared to that with sinus rhythm, (P<0.0001). There were strongly positive correlations between angiotensin II (Ang II) or procollagen type III-alpha-1 (COL3A1) with PDGF, Rac1, NF-κB, and among PDGF, Rac1 and NF-κB (all P<0.05). At 3 weeks after the transverse aorta constriction (TAC) operation in rat model and with intervention of irbesartan or/and simvastatin, the collagen volume fraction (CVF) and atrial natriuretic peptide (ANP) values respectively increased 6-folds and 3.5-folds in the TAC group compared to SHAM group (P<0.0001), but these levels decreased by 16% to 63% with following drug intervention (all P<0.0001), the combined treatment was the lowest. Accordingly, the expression levels of PDGF (3-folds), Rac1 (1.6-folds), NF-κB (7-folds) and AngII (12-folds) significantly increased in the TAC group compared to the SHAM group, and these levels were also reduced by 25% to 64% with following drug intervention. The highest reduction could be seen after treatment with irbesartan and simvastatin in combination (all P<0.001).There were strongly positive correlations between AngII or CVF with PDGF, Rac1, NF-κB, and among PDGF, Rac1 and NF-κB (all P<0.05).

CONCLUSIONS

Irbesartan or/and simvastatin can improve atrial fibrosis by regulating PDGF/Rac1/NF-κB axis.

Upstream therapy with statin and recurrence of atrial fibrillation after electrical cardioversion. Review of the literature and meta-analysis

Background

Atrial fibrillation (AF) is the most common sustained arrhythmia observed in clinical practice. Electrical cardioversion (EC) is commonly used to restore and maintain sinus rhythm but it is characterized by high rate of recurrences. Several trials analyzed the effects of statins to reduce the recurrences in AF with contradictory results.

Methods

We performed a meta-analysis of the interventional trials with statins in patients with persistent AF to evaluate recurrences after EC. Only randomized controlled trials were included in the analysis. Data sources included: Medline, ISI Web of Science, SCOPUS and Cochrane database (up to June 2012). Data extraction was performed by three authors. Study-specific odds ratios (ORs) were combined using fixed-effects model.

Results

Six studies with 515 patients were included in the analysis. Statins used in the selected trials were: atorvastatin (at dosages ranging from 10 to 80 mg/day), pravastatin (40 mg/day) and rosuvastatin (20 mg/day). AF recurrence after EC occurred in 108/258 (41.8%) of patients treated with statins and in 132/257 (51.3%) patients not on treatment with statins. Compared with control, recurrences were significantly reduced with statin treatment (O.R.: 0.662; 95% C.I., 0.45-0.96; p=0.03); statin treatment was associated with an absolute risk reduction of 0.095 and a number needed to treat of 11.

Conclusions

This review suggests that statin therapy was significantly associated with a decreased risk of recurrence in patients with persistent AF after EC.

The role of statin therapy in the prevention of atrial fibrillation: a meta-analysis of randomized controlled trials

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia, and AF is associated with relatively higher all-cause mortality in both men and women. However, there are limited treatment options for AF. Statins are hypothesized to have a benefit against arrhythmias in addition to well-established secondary prevention benefit for atherosclerotic coronary artery disease, yet the data are inconsistent

WHAT THIS STUDY ADDS

Statin therapy was significantly associated with a decreased risk of incidence or recurrence of AF. The benefit of statin therapy seemed more markedly in secondary prevention than primary prevention. These results provided some evidence for the benefit of statins beyond their lipid-lowering activity

AIMS

The use of statins has been suggested to protect against atrial fibrillation (AF) in some clinical observational and experimental studies but has remained inadequately explored. This study was designed to examine whether statins can reduce the risk of AF.

METHODS

Meta-analysis of randomized, controlled trials with use of statins on incidence or recurrence of AF was performed.

RESULTS

Twenty studies with 23,577 patients were included in the analysis. Seven studies investigated the use of statins in patients with AF, 11 studies investigated the primary prevention of statins in patients without AF, and two studies investigated mixed populations of patients. The incidence or recurrence of AF occurred in 1543 patients. Overall, statin therapy was significantly associated with a decreased risk of AF compared with control (odds ratio 0.49, 95% confidence interval 0.37-0.65; P < 0.00001). A beneficial effect was found in the atorvastatin subgroup and the simvastatin subgroup, but not in the pravastatin subgroup or the rosuvastatin subgroup. The benefit of statin therapy appeared to be more pronounced in secondary prevention (odds ratio 0.34, 95% confidence interval 0.18-0.64; P < 0.0008) than in primary prevention (odds ratio 0.54, 95% confidence interval 0.40-0.74; P < 0.0001).

CONCLUSIONS

Statin therapy was significantly associated with a decreased risk of incidence or recurrence of AF. Heterogeneity was explained by differences in statin types, patient populations and surgery types. The benefit of statin therapy seemed more pronounced in secondary than in primary prevention.

The preventive effect of statin therapy on new-onset and recurrent atrial fibrillation in patients not undergoing invasive cardiac interventions: a systematic review and meta-analysis

BACKGROUND

Previous meta-analyses suggest that pre-procedural use of statin therapy may reduce atrial fibrillation (AF) following invasive cardiac interventions (coronary artery by-pass grafting and percutaneous coronary intervention). However, the current evidence on the benefit of statins unrelated to invasive cardiac interventions has not been clarified systematically.

METHODS

Through a systematic literature search, trials examining the effect of statin therapy on AF were selected. Trials using statins before any percutaneous or surgical cardiac interventions were excluded.

RESULTS

The search identified 11 randomized and 16 observational eligible studies, totaling 106,640 patients receiving statin therapy and 129,305 serving as controls. Fourteen studies investigated the effect of statins on new-onset AF, 13 studies investigated the effect of statins on recurrent AF and one in both new-onset and recurrent AF. In the statin versus control group the mean age was 60.7 ± 8.3 versus 68.6 ± 6.2 years and females comprised 8.4% versus 10.3%. Statin therapy was associated with significant reduction of AF (Risk ratio (RR): 0.81 [95% confidence interval (CI): 0.80-0.83], p<0.001) combining all studies. Assessing exclusively randomized trials, statin therapy showed no significant risk reduction (RR: 0.97 [95%CI: 0.90-1.05], p=0.509), heterogeneity p>0.05. Assessing exclusively observational studies the risk reduction of new-onset AF was 12% (RR: 0.88 [95%CI: 0.85-0.91], p<0.001) and recurrent AF 15% (RR: 0.85 [95%CI: 0.80-0.90], p<0.001), heterogeneity p<0.001.

CONCLUSION

The hitherto published randomized clinical trials do not support a beneficial effect of statins on AF in patients not undergoing invasive cardiac interventions. This is in contrast to the results of observational and interventional studies.

Long-term efficacy of upstream therapy with lipophilic or hydrophilic statins on antiarrhythmic drugs in patients with paroxysmal atrial fibrillation: comparison between atorvastatin and pravastatin

There is little information available on the benefits of selection of statins as upstream therapy for the prevention of paroxysmal atrial fibrillation (AF). We compared the efficacy and safety of atorvastatin (A-group, n = 43) and pravastatin (P-group, n = 41) as upstream therapy in patients with paroxysmal AF and dyslipidemia. A total of 84 patients (45 men, mean age, 66 ± 9 years, mean follow-up, 49 ± 32 months) were retrospectively assigned to receive atorvastatin (n = 41;10 mg/day) or pravastatin (n = 43 ; 10 mg/day). Survival rates free from AF recurrence at 1, 6, 12, and 24 months were 93%, 74%, 60%, and 53% in A-group, and 88%, 49%, 37%, and 29%, respectively, in P-group (P = 0.029, A-group versus P-group). Survival rates free from conversion to permanent AF at 12, 36, 60, and 90 months were 100%, 100%, 98%, and 95% in A-group, and 100%, 95%, 88%, and 83%, respectively, in P-group (P = 0.063, A-group versus P-group). Using a logistic regression model, atorvastatin was found to be associated with a significantly reduced risk of AF recurrence in comparison to pravastatin (unadjusted odds ratio [OR] = 0.27, 95% confidence interval 0.11-0.68, P = 0.005). This association remained significant after adjustment for potentially confounding variables (OR = 0.26, 95% CI 0.08-0.86, P = 0.027). Using a logistic regression model, atorvastatin was not associated with a significantly reduced risk of converting to permanent AF in comparison to pravastatin (unadjusted OR = 0.29, 95% CI 0.05-1.50, P = 0.138), but this association did show a significant difference after adjustment for potentially confounding variables in a multivariate model (OR = 0.08, 95% CI 0.06-0.96, P = 0.046). Adverse effects requiring discontinuation of statins were observed in 1 case (2%, myalgia) in A-group, and 1 case (2%, elevation in CPK level ≥ 500 IU/L) in P-group, respectively (P = NS, A-group versus P-group). Atorvastatin, a lipophilic statin, was considered to be more effective in preventing recurrence of paroxysmal AF and conversion to permanent AF than pravastatin, a hydrophilic statin.

Statin therapy for the prevention of atrial fibrillation: a meta-analysis of randomized controlled trials

STUDY OBJECTIVES

To assess the efficacy of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) for primary and secondary prevention of atrial fibrillation, and to evaluate the efficacy of individual statins and their dosages.

DESIGN

Meta-analysis of 20 randomized controlled trials.

PATIENTS

A total of 32,311 patients who received either a statin (16,203 patients) or a placebo or active control regimen (16,108 patients) for either primary or secondary prevention of atrial fibrillation as part of a research study.

MEASUREMENTS AND MAIN RESULTS

A systemic literature search of MEDLINE, EMBASE, and the Cochrane Controlled Trials Register was performed to identify randomized controlled trials involving the prevention of atrial fibrillation with statin therapy. Effect size was expressed as odds ratio (OR) with 95% confidence interval (CI). Subgroup analysis was performed to explore the reasons for heterogeneity. Of the 20 trials, atorvastatin was studied in 11, pravastatin in five, rosuvastatin in three, and simvastatin in one. Overall, among the 32,311 patients in these trials, the risk of atrial fibrillation was significantly reduced by statins (OR 0.59, 95% CI 0.45-0.76), and the drugs were effective for both primary prevention (OR 0.67, 95% CI 0.51-0.88) and secondary prevention (OR 0.40, 95% CI 0.20-0.83). Secondary prevention was not superior to primary prevention, however. A significant benefit was observed in the atorvastatin-treated subgroup (OR 0.43, 95% CI 0.27-0.66), especially in the dose range of 10-40 mg/day (OR 0.29, 95% CI 0.19-0.45). No protective effect was observed in the pravastatin subgroup (OR 1.03, 95% CI 0.77-1.37).

CONCLUSION

This meta-analysis suggests that statin therapy is useful for the prevention of atrial fibrillation. The benefit of statins in secondary prevention was significant but not superior to primary prevention. Atorvastatin was more effective than pravastatin, and its effects were dose related, with lower doses being more effective. The number of trials focusing on individual drugs is still insufficient, and more randomized controlled trials are necessary to further support these conclusions.

Predictors of incident atrial fibrillation and influence of medications: a retrospective case-control study

BACKGROUND

Atrial fibrillation (AF) is a common condition, associated with raised mortality and risk of major morbidity, and is predicted to increase due to an aging population.

AIM

To update earlier research of AF predictors using UK data.

DESIGN AND SETTING

Case-control analysis of adults aged 18 years and older with a diagnosis of AF in practices registered with the General Practice Research Database (GPRD) in the UK.

METHOD

Using the GPRD, a case.control analysis was performed using logistic regression to compare 55,412 incident AF cases to 216,400 controls, for medical history and prior use of drugs. The association between time since start of diagnosis or drug use and AF risk was summarised using Spline regression.

RESULTS

The following were confirmed as risk factors for AF: heart failure (risk ratio [RR] 2.91 [95% CI = 2.59 to 3.27]); ischaemic heart disease (IHD) (RR 2.00 [95% CI = 1.78 to 2.24]); hypertension (RR 2.60 [95% CI = 2.32 to 2.92]); hyperthyroidism (RR 1.56 [95% CI = 1.39 to 1.75]); being a heavy drinker (RR 1.43 [95% CI = 1.27 to 1.60]); cerebrovascular accident (RR 1.48 [95% CI = 1.32 to 1.66]); and obesity (body mass index ≥30 kg/m(2) RR 1.29 [95% CI = 1.15 to 1.45]). Current use of oral glucocorticoids (RR 1.62 [95% CI = 1.44 to 1.82]) and of beta-2 agonists (RR 1.30 [95% CI = 1.16 to 1.46]) were identified as significant risk factors, and statins (RR 0.82 [95% CI = 0.73 to 0.92]) as a significant protective factor. No effect was found for current use of bisphosphonates (RR 0.95 [95% CI = 0.85 to 1.07]), renin.angiotensin.aldosterone system (RAAS) agents (RR 1.04 [95% CI = 0.93 to 1.17]), or xanthine derivatives (RR 1.09 [95% CI = 0.97 to 1.22]). Spline regression analysis found the effect of heart failure, IHD, use of oral glucocorticoids, and use of statins on the likelihood of developing AF was sustained over a number of years.

CONCLUSION

These findings update the risk factors that are associated with AF, and confirm the protective properties of statins and the risks of beta-2 agonists in developing AF, but not the supposed protective qualities of glucocorticoids and RAAS agents.

The effects of statin on atrial fibrillation: a meta-analysis of published data from randomized controlled trials

BACKGROUND

Some clinical and experimental studies have shown the use of statins could protect against AF, but there are not adequate data at present.

OBJECTIVES

We performed a meta-analysis of randomized trials with statins on the endpoint of incidence of AF to estimate the impact of statin use on AF development.

METHODS

We searched PUBMED, EMBASE and the Cochrane controlled Trials Register (Cochrane Library Issue 4, 2010) up to November 2010 to identify studies covering the use of statins on atrial fibrillation.

RESULTS

In published data from nine short term trials (1044 patients, 421 AF), the effect of statins was significantly associated with a decreased risk of recurrence of AF (OR 0.43, 95% CI 0.25 to 0.73, P = 0.002). The result of OR was higher when studies with Jadad score ≤3 were excluded (OR 0.32, 95% CI 0.18 to 0.54, P ≤ 0.0001). Among four long term trials (12,442 patients, 618 AF), the effect of statins was associated with a decreased risk of recurrence of AF (OR 0.81, 95% CI 0.68 to 0.97, P = 0.02). In three long term trials of more intensive versus standard statin (9130 patients, 188 AF), there was no evidence of a reduction in the risk of AF (OR 1.05, 95% CI 0.79 to 1.40, P= 0.74).

CONCLUSION

Our meta-analysis suggests that the use of statins may be associated with preventing AF in short term trials and long term trials, but in the long term trials of more intensive versus standard statin, there was no evidence of a reduction in the risk of AF. However, we still need large-scale randomized double blind statin trials with AF occurrence as the main endpoint in order to finally confirm the benefits of statin in AF patients.

Upstream therapies for management of atrial fibrillation: review of clinical evidence and implications for European Society of Cardiology guidelines. Part II: secondary prevention

Fundamental research into molecular mechanisms of atrial fibrillation (AF) and improved understanding of processes involved in the initiation and maintenance of AF have transformed the traditional approach to its management by targeting only the electrical aspects, usually with antiarrhythmic drugs and, recently, by ablation. The antiarrhythmic potential of upstream therapies, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers (ARBs), statins, and n-3 (ω-3) polyunsaturated fatty acids, extends beyond the benefit of treating underlying heart disease to modifying the atrial substrate and intervening in specific mechanisms of AF. The key target is structural remodelling of the atria, particularly inflammation and fibrosis, although there is evidence to suggest the direct involvement at the ion channel level. Positive clinical reports supported by robust experimental data have suggested that upstream therapies can be valuable strategies for primary prevention of AF in selected patients and have resulted in several class IIA recommendations in the new European guidelines on AF. However, these results have not been consistently replicated in the secondary prevention setting, and several recent randomized controlled studies failed to demonstrate any effect of upstream therapies on AF burden or on major cardiovascular outcomes. Part II of the review summarizes the evidence base for the use of upstream therapies for secondary prevention of AF.

Statin treatment for patients with paroxysmal atrial fibrillation

Recent clinical evidence and animal experiments support the belief that statins have beneficial effects on cardiovascular outcomes and prevention of atrial fibrillation (AF). We investigated whether the use of statins reduces the mortality, morbidity, and recurrence rate of AF in patients with paroxysmal AF. A post hoc analysis of the Japanese Rhythm Management Trial for Atrial Fibrillation (J-RHYTHM) study was conducted.Of the 823 patients with paroxysmal AF in the J-RHYTHM study, 101 (12.3%) were receiving a statin at baseline. Patients taking statins were older and more likely to have hypertension, dyslipidemia, coronary artery disease, and ischemic stroke compared to patients not taking statins. During a mean follow-up period of 19.3 months, 40 patients (5.5%) reached the primary endpoint (a composite of all-cause death, stroke, systemic embolism, major bleeding, and hospitalization for heart failure) and 140 patients (19.4%) experienced a recurrence of AF. Multivariate Cox proportional-hazard regression analysis revealed statin use was not associated with improved mortality and morbidity (hazard ratio [HR] 0.409, 95% confidence interval [CI] 0.113-1.482), or a decreased risk of AF recurrence (HR 0.662, 95% CI 0.299-1.466).This analysis provides evidence that statin use did not affect clinical outcomes in patients with paroxysmal AF and emphasizes the need for randomized clinical trials defining more clearly the role of statins in treating AF.

High-dose atorvastatin and risk of atrial fibrillation in patients with prior stroke or transient ischemic attack: analysis of the Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial

BACKGROUND

Observational analyses and short-term randomized trials have suggested that statins reduce occurrence or recurrence of atrial fibrillation (AF). We tested the hypothesis that long-term treatment with high-dose atorvastatin reduces occurrence of AF in patients with prior stroke or transient ischemic attack.

METHODS

We examined development of new AF in the SPARCL trial that compared atorvastatin 80 mg daily with placebo in 4,731 patients with prior stroke or transient ischemic attack. Patients who had chronic or paroxysmal AF or were taking medications for treatment or prophylaxis of AF at the time of enrollment were excluded. Atrial fibrillation was identified from electrocardiograms submitted to a blinded central electrocardiographic laboratory and from investigators' adverse event reports.

RESULTS

Patients were followed up for a median of 4.8 years, corresponding to >20,000 patient-years of observation with a median of 5 electrocardiograms per patient. The primary efficacy measure, the time from randomization to first occurrence of new AF, did not differ between treatment groups. By intention to treat, there were 139 cases of new AF in the atorvastatin group and 122 cases in the placebo group, corresponding to incidence rates of 1.32 and 1.14 cases per 100 patient-years observation (hazard ratio 1.15, 95% CI 0.90-1.46, P = .26). On-treatment analysis yielded similar findings, with incidence rates of 1.26 and 1.01 cases per 100 patient-years observation in the atorvastatin and placebo groups, respectively (hazard ratio 1.25, 95% CI 0.94-1.67, P = .12).

CONCLUSION

High-dose atorvastatin does not prevent development of AF in patients with prior stroke or transient ischemic attack.

Update on the association of inflammation and atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia and is associated with significant morbidity and mortality. The pathogenesis of AF remains incompletely understood and management remains a difficult task. Over the past decade there has been accumulating evidence implicating inflammation in the pathogenesis of AF. Inflammation appears to play a significant role in the initiation and perpetuation of AF as well as the prothrombotic state associated with AF. Inflammatory biomarkers (C-reactive protein and interleukin-6) have been shown to be associated with the future development, recurrence and burden of AF, and the likelihood of successful cardioversion. Therapies directed at attenuating the inflammatory burden appear promising. Animal and clinical studies have evaluated statins, angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers, and corticosteroids for the treatment or prevention of AF. The purpose of this review is to provide current evidence on the relationship between inflammation and AF and potential therapies available to modulate the inflammatory state in AF.

Atorvastatin given prior to electrical cardioversion does not affect the recurrence of atrial fibrillation in patients with persistent atrial fibrillation who are on antiarrhythmic therapy

OBJECTIVE

In this study, our aim was to evaluate the effect of a higher dose of atorvastatin on the recurrence rate of atrial fibrillation (AF) after electrical cardioversion (EC) in addition to antiarrhythmic therapy.

SUBJECTS AND METHODS

48 patients with persistent AF were included in this study. The patients were randomized to an atorvastatin 40-mg treatment group and a control group. Atorvastatin was started 3 weeks before EC and was continued for 2 months after EC. EC was performed using biphasic shocks after 3 weeks of treatment with the orally administered anticoagulant warfarin. Lipid and inflammatory parameters (high-sensitivity C-reactive protein, white blood cell count and fibrinogen level) were evaluated at the baseline and before EC. The endpoint of this study was electrocardiographically confirmed recurrence of AF of >10 min.

RESULTS

There were no significant differences in baseline characteristics and lipid and inflammatory marker levels between the treatment and control groups. Total cholesterol and low-density lipoprotein levels were significantly decreased in patients taking atorvastatin for 2 months compared with baseline values (174 ± 31 vs. 129 ± 25 mg/dl, p = 0.001, and 112 ± 23 vs. 62 ± 20 mg/dl, p = 0.001, respectively), while no significant change occurred in control patients (168 ± 26 vs. 182 ± 29 mg/dl, p = 0.07, and 99 ± 18 vs. 108 ± 26 mg/dl, p = 0.1, respectively). At the end of the 2-month follow-up period, 9 patients (20.5%) experienced AF recurrence, and there was no significant difference in AF recurrence rate between the treatment and control groups (26 vs. 13%; p = 0.2).

CONCLUSION

Atorvastatin therapy prior to EC does not prevent the recurrence of arrhythmia in patients with persistent AF who are receiving antiarrhythmic therapy.

Upstream effect for atrial fibrillation: still a dilemma?

Atrial fibrillation is the most common arrhythmia in clinical practice. Ion channel blocking agents are often characterized by limited long-term efficacy and several side effects. In addition, ablative invasive procedures are neither easily accessible nor always efficacious. The "upstream therapy," which includes angiotensin-converting enzyme inhibitors, aldosterone receptor antagonists, statins, glucocorticoids, and ω-3 poly-unsaturated fatty acids, targets arrhythmia substrate, influencing atrial structural and electrical remodeling that play an essential role in atrial fibrillation induction and maintenance. The mechanisms involved and the most important clinical evidence regarding the upstream therapy influence on atrial fibrillation are presented in this review. Some open questions are also proposed.

Statin therapy for the prevention of atrial fibrillation trial (SToP AF trial)

BACKGROUND

Inflammation and oxidative stress are associated with atrial fibrillation (AF). Statins have antioxidant and anti-inflammatory properties. We tested if atorvastatin reduced AF recurrence after DC cardioversion (CV) by modifying systemic oxidative stress and inflammation (NCT00252967).

METHODS AND RESULTS

In a randomized, double-blinded, placebo-controlled trial, patients with atrial fibrillation/flutter (AF) were randomized to receive either atorvastatin 80 mg (n = 33) or placebo (n = 31) before CV. Treatment was continued for 12 months or until AF recurred. Serum oxidative stress markers (ratios of oxidized to reduced glutathione and cysteine, derivatives of reactive oxygen species, isoprostanes) and inflammatory markers (high-sensitivity C- reactive protein [hs-CRP], interleukin-6 [IL-6], interleukin-1β[IL-1β], tumor necrosis factor alpha [TNFα]) were measured at baseline and on follow-up. AF recurred in 22 (66.7%) of atorvastatin and 26 (83.9%) of placebo group (P = 0.2). The adjusted hazard ratio of having recurrence on atorvastatin versus on placebo was 0.99 (95% CI: 0.98-1.01, P = 0.3). There was no significant difference in the time to recurrence using Kaplan-Meier survival estimates (median [IR]: 29 [2-145] days versus 22 [7-70] days, P = 0.9). Although no significant effect was seen on oxidative stress, 2 of 4 inflammatory markers, IL-6 (adjusted OR: 0.59, 95% CI: 0.35-0.97, P = 0.04) and hs-CRP (adjusted OR: 0.59, 95% CI: 0.37-0.95, P = 0.03) were significantly lowered with atorvastatin. Cholesterol levels significantly decreased with atorvastatin (P = 0.03).

CONCLUSIONS

High-dose atorvastatin did not reduce the recurrence of AF after CV. It reduced selective markers of inflammation without affecting systemic oxidative stress. Failure of atorvastatin to prevent AF recurrence may be due to its failure to affect oxidative stress.

Atrial fibrillation and inflammation

Atrial fibrillation (AF) is the most common clinical arrhythmia. Recent investigations have suggested that inflammation might have a role in the pathophysiology of AF. In this review, the association between inflammation and AF, and the effects of several agents that have anti-inflammatory actions, such as statins, polyunsaturated fatty acids, corticosteroids and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, have been investigated.

Non-antiarrhythmic drugs to prevent atrial fibrillation

Atrial fibrillation (AF) is the most frequent arrhythmia found in clinical practice. The majority of patients with AF are still candidates for antiarrhythmic drug treatment, not only for acute reversion to sinus rhythm but also for long-term treatment to prevent recurrences of AF. Currently available antiarrhythmic drugs, however, are unable to provide complete efficacy in all patients, and present problematic risks of proarrhythmia. The progressively increasing prevalence of AF supports the need to develop improved therapeutic approaches for the clinical management of arrhythmia. Accordingly, new treatment techniques aimed at suppressing the origin of the arrhythmogenic foci have been developed in the last decade. However, ablative treatments are only available for selected patients. Because of these factors, and also because primary prevention of AF should be our goal, the introduction of non-antiarrhythmic agents that could prevent both new-onset AF and recurrences of AF may eventually improve patient outcomes and reduce the incidence of this epidemic disease. The potential clinical value of these non-antiarrhythmic options is currently under active investigation. There is now clinical and experimental evidence that many drugs may have beneficial effects in preventing AF through several possible mechanisms. Non-antiarrhythmic drugs, such as ACE inhibitors and angiotensin receptor blockers, HMG-CoA reductase inhibitors (statins), corticosteroids, and N-3 polyunsaturated fatty acids may have a positive effect in patients with AF or in preventing AF in patients at risk.

Lack of effect of statins on maintenance of normal sinus rhythm following electrical cardioversion of persistent atrial fibrillation

Randomised controlled trials evaluating the effect of statin use on maintenance of normal sinus rhythm (NSR) after electrical cardioversion (ECV) of persistent atrial fibrillation (AF) have demonstrated conflicting results. However, many of these trials were of relatively small size and thus underpowered to adequately evaluate this end-point. The aim of this study was to conduct a meta analysis evaluating the effect of statin use on maintenance of NSR after ECV of persistent AF. Randomised controlled trials evaluating the use of statins to maintain NSR after ECV of AF were identified through a systematic search including Medline (1950 through December 2009), the Cochrane CENTRAL Register (4th quarter, 2009) and a manual review of references without any language restrictions. Pooled estimates of effect are reported as relative risks (RRs) with accompanying 95% confidence intervals (CIs) using a random-effects model. Four trials (n = 424; range: 48-212) were identified and subject to meta analysis. Evaluated statins included atorvastatin 10 and 80 mg and pravastatin 40 mg/day. Over a mean of 2.1 months (range: 1-3 months) statins did not increase the likelihood of maintaining NSR following ECV (RR, 1.12; 95%CI, 0.85-1.46) compared with control. Current evidence does not suggest that statins are associated with an increased probability of maintaining NSR following ECV of persistent AF.

Adjuvant therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging US population and affecting more than 2.3 million people. Current approaches for managing AF are rate- or rhythm-control strategies, both using anti-thrombotic therapy to prevent thromboembolism. While great advances have been made in understanding the pathophysiology of AF, few new strategies have shown promise in prevention or treatment of AF. Recent data suggest that non-antiarrhythmic medication may be useful in modifying the substrate that allows AF precipitation and perpetuation. This article reviews the data on the role of these agents in the prevention and management of AF as an adjunct to standard therapy.

Non-atheroprotective effects of statins: a systematic review

Since the introduction of HMG-CoA reductase inhibitors (statins) for lowering lipids, a large amount of data has been published demonstrating their potential benefits in conditions as varied as cancer, osteoporosis, and Alzheimer's dementia. We reviewed the published literature on MEDLINE from articles between 1950 and 2008 on the non-atheroprotective effects of statins and noted consistent benefits of statin use in improving outcomes of ventricular arrhythmias, sudden cardiac death, cardiac transplant rejection, chronic obstructive pulmonary disease, and sepsis. However, for these conditions, the level of evidence was inadequate to recommend statin use. The evidence for improving outcomes in atrial fibrillation, mortality in heart failure, contrast-induced nephropathy, cataract, age-related macular degeneration, sub-arachnoid hemorrhage, osteoporosis, dementia, and cancer incidence was conflicting and inconclusive. Furthermore, we found that most of the literature consists of small observational studies and their conclusions are often not corroborated by results from larger or randomized studies. Pending large, well designed, randomized trials, we conclude that there is no definite evidence for the use of statins in any condition besides hyperlipidemia and atherosclerosis.

Statins as antiarrhythmics: a systematic review part I: effects on risk of atrial fibrillation

BACKGROUND

Recent studies have demonstrated that statins may possess antiarrhythmic properties in addition to their lipid-lowering effects.

METHODS

Studies which reported the association of statins with the incidence of atrial arrhythmias were identified through a systematic review of published literature.

RESULTS

One randomized, placebo-controlled trial of 200 patients undergoing cardiac surgery showed that atorvastatin decreased the incidence of postoperative atrial fibrillation by 61%. Observational studies in patients with stable coronary disease, left ventricular dysfunction, or those undergoing cardiac or noncardiac surgery show that statin therapy is associated with an approximately 50% lower rate of atrial fibrillation. Two small randomized trials reported conflicting results: one showing that atorvastatin reduced the recurrence of AF after electrical cardioversion and the other finding that pravastatin did not.

CONCLUSIONS

Published data suggests that statins may possess antiarrhythmic properties that reduce the propensity for atrial fibrillation. Most of this data is observational; more randomized, placebo-controlled trials are needed.

Primary and secondary prevention of atrial fibrillation with statins and polyunsaturated fatty acids: review of evidence and clinical relevance

Atrial fibrillation (AF) is an increasingly common arrhythmia that now stands at epidemic proportion, with more than 2.3 million people affected in the USA and over 4.5 million people affected in Western Europe. AF is an expression of underlying heart disease and is increasingly associated with hypertension, congestive heart failure, and ischemic heart disease. It is also a progressive disease secondary to continuous structural remodeling of the atria, which relates to AF itself, to changes associated with aging and to progression of the underlying heart disease. Traditionally, AF has been addressed only after it has already presented with pharmacological and nonpharmacological therapies designed for rhythm or rate control (secondary prevention). Although secondary prevention is the most feasible approach at present, the concept of primary prevention of AF with therapies aimed at preventing the development of substrate and correcting the risk factors for AF has emerged as a strategy, which is likely to produce a larger effect in the general population. Recent experiments provided new insights into AF pathophysiology, which generated background for new mechanism-based therapies. Agents targeting inflammation, oxidative injury, atrial myocyte metabolism, extracellular matrix remodeling, and fibrosis have theoretical advantages as novel therapeutic strategies. In this respect, drugs that are not traditionally antiarrhythmic such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, aldosterone antagonists, statins, and omega-3 polyunsaturated fatty acids have shown an antiarrhythmic potential in addition to any treatment effect on the underlying disease. These agents are thought to have an advantage of targeting both the occurrence and progression of the substrate for AF, thus, providing primary and secondary prevention of the arrhythmia. Although first experimental and hypothesis-generating small clinical studies or retrospective analyses have been encouraging, several larger, properly designed, prospective trials have not confirmed earlier observations. This review provides a contemporary evidence-based insight into the possible preventative and reverse remodeling role of statins and polyunsaturated fatty acids in AF.