Comparison of frequency of new-onset atrial fibrillation or flutter in patients on statins versus not on statins presenting with suspected acute coronary syndrome

Atrial Fibrillation Complicating Acute Myocardial Infarction: Prevalence, Impact, and Management Considerations

PURPOSE OF REVIEW

Atrial fibrillation (AF) and myocardial infarction (MI) often coexist, and this overlapping nature leads to heightened morbidity and increases the need for comprehensive risk management strategies. The precise trajectory and implications of atrial fibrillation complicating myocardial infarction remain subjects of debate, with divergent reports presenting varying accounts. This review seeks to provide an in-depth exploration of the existing literature to cover the predictors, implication, and available management of new onset atrial fibrillation (NOAF) complicating acute myocardial infarction (AMI).

RECENT FINDINGS

Clinical risk factors, laboratory markers, echocardiographic findings, and angiographic data can be used to assess patients at risk of developing NOAF post-AMI. The diagnosis of NOAF post MI has been associated with overall worse short- and long-term prognosis with increased risk for mortality, cardiogenic shock, stroke, and bleeding, along with reduced rates of coronary angiography and percutaneous coronary intervention, and higher risk of future recurrence of AF and ischemic stroke. Despite the paucity of preventative treatment, the optimal management of acute coronary syndrome and the use of guideline directed therapy do decrease the risk of development of atrial fibrillation post myocardial infarction.

Prior statin use and the incidence of in-hospital arrhythmia in acute coronary syndrome: A systematic review and meta-analysis

BACKGROUND

The benefit of prior statin use to reduce the incidence of arrhythmia in acute coronary syndrome (ACS) is still a matter of debate. Statins have multiple pleiotropic effects, which may reduce the incidence of in-hospital arrhythmia. A systematic review and meta-analysis were performed to evaluate prior statin use and the incidence of in-hospital arrhythmia in ACS.

METHODS

This systematic review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We performed a literature search through Pubmed, Proquest, EBSCOhost, and Clinicaltrial.gov. A random-effect model was used due to moderate heterogeneity. Quality assessment was performed using Newcastle Ottawa Scale. Sensitivity analysis was performed by using leave one or two out method. PROSPERO registration number: CRD42022336402.

RESULTS

Nine eligible studies consisting of 86,795 patients were included. A total of 22,130 (25.5%) patients were in statin use before the index ACS event. The prevalence of old myocardial infarction, heart failure, hypertension, diabetes mellitus, and chronic renal failure and concomitant treatment with aspirin, clopidogrel, and beta blocker was higher in the prior statin group compared to no previous statin. Overall, prior statin use was associated with a significantly lower incidence of in-hospital arrhythmia during ACS compared to no previous statin (OR 0.60; 95% CI 0.49-0.72; P < 0.00001; I2 = 54%, P-heterogeneity = 0.03). In subgroup analysis, previous statin use reduced the incidence of atrial fibrillation or atrial flutter (OR 0.64; 95% CI 0.43-0.95; P = 0.03; I2 = 73%, P-heterogeneity = 0.01) and ventricular tachycardia or ventricular fibrillation (OR 0.57; 95% CI 0.49-0.65; P < 0.00001; I2 = 8%, P-heterogeneity = 0.35).

CONCLUSIONS

Based on aggregate patient data, prior statin use may reduce the incidence of in-hospital arrhythmia during ACS, particularly atrial fibrillation or atrial flutter and ventricular tachycardia or ventricular fibrillation.

Coronary Flow Disturbance Phenomenon After Percutaneous Coronary Intervention Is Associated with New-Onset Atrial Fibrillation in Patients with Acute Myocardial Infarction

Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI). Although previous studies have investigated mortality rates and the incidences of adverse events associated with new-onset AF (NOAF) in patients with AMI, the effects of emergency percutaneous coronary intervention (PCI) on the incidence of NOAF in patients with AMI remain unclear. The purpose of this study was to investigate the relationship of clinical characteristics, medical history, and the coronary flow disturbance phenomenon (TIMI < 3) following emergency PCI with NOAF in patients with AMI. Between 2012 and 2016, 731 patients with AMI underwent PCI at our facility. Among these, 52 had a history of chronic/paroxysmal AF before admission and were excluded. The remaining 679 patients (mean age 66.4 years, 532 males) were analyzed in this retrospective observational study.New-onset AF was observed in 45 patients (6.6%). In univariate analysis, the hazard ratios (HRs) for patient age (HR 1.04, 95%CI 1.02-1.07), Killip II-IV (HR 2.34, 95%CI 1.29-4.23), elevated D-dimer level (> 1.0 μg/mL; HR 3.32; 95%CI 1.77-6.23), and coronary flow disturbance phenomenon (HR 5.61; 95%CI 2.88-10.9) were significantly higher in the NOAF group. In multivariate analysis, an elevated D-dimer level (> 1.0 μg/mL; HR 2.44; 95%CI 1.17-5.11) and coronary flow disturbance phenomenon (HR 4.61; 95%CI 2.29-9.27) were found to be independent risk factors for NOAF. An elevated D-dimer level at admission and the presence of coronary flow disturbance phenomenon after PCI were risk factors for NOAF following emergency PCI in patients with AMI.

Efficacy of atorvastatin in prevention of atrial fibrillation after heart valve surgery in the PROFACE trial (PROphylaxis of postoperative atrial Fibrillation After Cardiac surgEry)

Background

To evaluate the efficacy of perioperative atorvastatin administration for prophylaxis of postoperative atrial fibrillation (POAF) after heart valve surgery.

Methods

Our study included 90 patients with heart valve disease who were scheduled to undergo elective cardiac surgery. Cases with previous AF or preoperative beta-blocker therapy were excluded. Patients were randomized into the atorvastatin group, which included 47 patients who received 40 mg/day of atorvastatin 7 days before and after the surgery and the control group, which included 43 patients. Primary endpoint was the occurrence of POAF. Secondary endpoints included modifications in the preoperative and postoperative levels of the markers of inflammation (C-reactive protein [CRP]), myocardial injury (ultrasensitive troponin T and creatinine phosphokinase MB [CPK-MB]), and cardiac dysfunction (pro-brain natriuretic peptide [proBNP]) related to POAF and changes in the echocardiographic parameters, such as atrial electromechanical interval, A wave, E/A ratio, and Doppler imaging systolic velocity wave amplitude, related to POAF.

Results

No relationship between atorvastatin administration and reduction in the incidence of POAF was observed (42.6% in the atorvastatin vs. 30.2% in the control group) (p=0.226). No difference in the levels of CPK-MB, ultrasensitive troponin T, CRP, or proBNP and in the analyzed echocardiographic parameter was detected between both groups.

Conclusions

Atorvastatin in the described dose, was not adequate for the prophylaxis of POAF after heart valve surgery. It was ineffective in controlling the inflammatory phenomena, myocardial injury, and echocardiographic predictors of POAF.

Association between the use of renin-angiotensin system blockers and development of in-hospital atrial fibrillation in patients with ST-segment elevation myocardial infarction

BACKGROUND AND AIM

Atrial fibrillation (AF) is the most common supraventricular arrhythmia following ST-segment elevation myocardial infarction (STEMI). We evaluated the association between use of previous angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers (renin-angiotensin system [RAS] blockers) and started RAS blockers after MI and development of AF in patients presenting with acute STEMI.

MATERIALS AND METHODS

This retrospective study enrolled 1000 patients with acute STEMI who were admitted to the coronary care unit. Patients were divided into groups according to the use of RAS blockers before MI and development of AF rates was compared. Predictors of AF were determined by multiple logistic regression analysis.

RESULTS

Of the 1000 patients presenting with STEMI, 247 received and 753 did not receive RAS blockers. The incidence of AF was 7.9%. The incidence of AF in patients receiving RAS blockers and did not receiving RAS blockers before MI were similar (5.7% vs. 8.6% respectively, P=0.13). On the other hand, AF rate was lower in patients in whom RAS blockers were administered during MI as compared to those in whom these agents were not administered (7.2% vs. 28.6%, P<0.001). Multiple regression analysis results showed that administration of RAS blockers or statins during hospitalization and left atrial diameter were associated with development of AF in patients with acute STEMI.

CONCLUSIONS

Previous therapy with RAS blockers does not reduce the incidence of AF in STEMI. Administration of RAS blockers at the hospital may decrease the AF rate in STEMI.

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.

Mechanisms of new-onset atrial fibrillation complicating acute coronary syndrome

Atrial fibrillation (AF) is one of the most common arrhythmia complications of acute coronary syndrome (ACS). The incidence of new-onset AF is 2.3-37 %, and it is an important predictor of a patient's morbidity, mortality, and prolonged hospitalization. Various risk factors for the development of new-onset AF after ACS have been identified, including: old age, higher Killip class, relevant history (e.g., hypertension), and enlarged left atrium. Insights into the pathophysiological mechanisms of new-onset AF have been provided by both experimental and clinical investigations and show that new-onset AF is multifactorial, involving atrial ischemia and atrial stretch, inflammation, autonomic nervous system activity, and hormone activation. An understanding of the mechanisms underlying new-onset AF complicating ACS can provide new insight of therapeutic importance.

Prognostic impact of atrial fibrillation occurrence in patients with non-ST-elevation acute coronary syndromes: is dysrhythmia duration a parameter to focus on?

Several studies have evaluated the prognostic impact of atrial fibrillation (AF) in ST-elevation myocardial infarction (STEMI) patients, but scarce data are available on the role of AF in non-ST-elevation acute coronary syndromes (NSTE-ACS). The aim of this study was to investigate long-term outcome of NSTE-ACS patients experiencing an episode of AF during in-hospital course. Of 1,147 NSTE-ACS patients, 54.4% for non-STEMI (NSTEMI) and 45.6% for unstable angina, 65 (5.7%) had an episode of AF. Long-term survival was compared with that of 1,082 NSTE-ACS patients who did not develop AF. Patients who developed AF, with respect to those who did not, were older and more frequently with NSTEMI at admission (69.2 vs. 53.5%, p = 0.013), diabetes, dyslipidemia and history of heart failure. Moreover, patients who developed AF had a significantly higher New York Heart Association class and lower values of glomerular filtration rate. During a median follow-up of 40.7 months, we observed a significantly higher mortality in NSTE-ACS patients who developed AF versus those who did not (42.2 vs. 19.8%, p < 0.001). AF occurrence in NSTE-ACS was a significant predictor of mortality at Cox regression (adjusted HR: 1.85; p = 0.03). After propensity score analysis, only patients with AF duration >6 h showed a significantly higher mortality at Cox regression (p = 0.021). Our results suggest that NSTE-ACS patients who develop AF are characterized by a higher clinical complexity. The occurrence of AF, when longer than 6 h, represents an important negative prognostic factor for long-term survival.

Atrial fibrillation in acute ST-elevation myocardial infarction: clinical and prognostic features

Atrial fibrillation (AF) is a common arrhythmia in the setting of acute coronary syndrome and acute ST-elevation myocardial infarction (STEMI). This review summarizes recent evidence on the clinical and prognostic significance of pre-existent and new-onset AF in acute STEMI patients and highlights new emerging predictors of AF development in the era of contemporary treatment.

Statins therapy can reduce the risk of atrial fibrillation in patients with acute coronary syndrome: a meta-analysis

BACKGROUND

It is a controversy whether statins therapy could be beneficial for the occurrence of atrial fibrillation (AF) in acute coronary syndrome (ACS). To clarify this problem, we performed a meta-analysis with the currently published literatures.

METHODS

The electronic databases were searched to obtain relevant trials which met the inclusion criteria through October 2011. Two authors independently read the trials and extracted the related information from the included studies. Either fixed-effects models or random-effects models were assumed to calculate the overall combined risk estimates according to I(2 )statistic. Sensitivity analysis was conducted by omitting one study in each turn, and publication bias was evaluated using Begg's and Egger's test.

RESULTS

Six studies were eligible to inclusion criteria, of the six studies, 161305 patients were included in this meta-analysis, 77920 (48.31%) patients had taken the statins therapy, 83385 (51.69%) patients had taken non-statins therapy. Four studies had investigated the effect of statins therapy on occurrence of new-onset AF in ACS patients, another two had described the association between statins therapy and occurrence of AF in ACS patients with AF in baseline. The occurrence of AF was reduced 35% in statins therapy group compared to that in non-statins group (95% confident interval: 0.55-0.77, P<0.0001), and the effect of statins therapy seemed more beneficial for new-onset AF (RR=0.59, 95%CI: 0.48-0.73, p=0.096) than secondary prevention of AF (RR=0.70, 95%CI: 0.43-1.14, p=0.085). There was no publication bias according to the Begg's and Egger's test (Begg, p=0.71; Egger, p=0.73).

CONCLUSION

Statins therapy could reduce the risk of atrial fibrillation in patients with ACS.

Atrial Fibrillation Complicating Acute Coronary Syndromes

Atrial fibrillation frequently complicates myocardial infarction. Patients with atrial fibrillation complicating acute coronary syndrome have increased morbidity and mortality relative to patients that remain in normal sinus rhythm. No studies have identified a mortality benefit to rhythm control compared with rate control in the setting of acute coronary syndrome. Stroke prevention should be pursued with oral anticoagulation therapy, although the majority of patients with atrial fibrillation associated with acute coronary syndrome receive only antiplatelet therapy. There are several novel oral anticoagulant therapies now available, but these agents have not been well studied in combination with dual antiplatelet therapy. Therefore, warfarin as part of triple therapy is the most conservative approach until additional data becomes available.

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.

Statins reduce short- and long-term mortality associated with postoperative atrial fibrillation after coronary artery bypass grafting: impact of postoperative atrial fibrillation and statin therapy on survival

BACKGROUND

Postoperative atrial fibrillation (POAF) is a frequent complication of coronary artery bypass grafting (CABG) surgery. The objective of this study was to determine the impact of POAF on both short- and long-term mortality following isolated CABG.

HYPOTHESIS

POAF is associated with a poorer short and long-term mortality following CABG.

METHODS

We retrospectively analyzed the preoperative and operative data of 6728 consecutive patients undergoing a first isolated CABG.

RESULTS

The incidence of POAF was 27.8%. Operative mortality was higher in patients with POAF compared to those without POAF (2.3% vs 0.9%, P < 0.001). On multivariate analysis, POAF remained an independent predictor of operative mortality (odds ratio [OR]: 1.78, P = 0.01). Patients with POAF also had reduced long-term survival (6-year survival: 85.3% vs 89.2%, P < 0.001). After adjusting for other predictors of mortality, POAF was significantly associated with increased long-term mortality (hazard ratio [HR]: 1.35, P = 0.04). Of note, after adjustment for potential confounders, statin treatment had a highly protective effect in POAF patients for both operative mortality (OR: 0.38, P = 0.003) and long-term mortality (HR: 0.62, P = 0.03), whereas it had no significant effect in patients without POAF.

CONCLUSIONS

POAF is an independent predictor of both short- and long-term mortality following CABG. Moreover, statin therapy was independently associated with better survival in patients with POAF.

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

Atrial fibrillation (AF) is associated with significant morbidity and mortality. It is also a progressive disease secondary to continuous structural remodelling of the atria due to AF itself, to changes associated with ageing, and to deterioration of underlying heart disease. Current management aims at preventing the recurrence of AF and its consequences (secondary prevention) and includes risk assessment and prevention of stroke, ventricular rate control, and rhythm control therapies including antiarrhythmic drugs and catheter or surgical ablation. The concept of primary prevention of AF with interventions targeting the development of substrate and modifying risk factors for AF has emerged as a result of recent experiments that suggested novel targets for mechanism-based therapies. Upstream therapy refers to the use of non-antiarrhythmic drugs that modify the atrial substrate- or target-specific mechanisms of AF to prevent the occurrence or recurrence of the arrhythmia. Such agents include angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), statins, n-3 (ω-3) polyunsaturated fatty acids, and possibly corticosteroids. Animal experiments have compellingly demonstrated the protective effect of these agents against electrical and structural atrial remodelling in association with AF. The key targets of upstream therapy are structural changes in the atria, such as fibrosis, hypertrophy, inflammation, and oxidative stress, but direct and indirect effects on atrial ion channels, gap junctions, and calcium handling are also applied. Although there have been no formal randomized controlled studies (RCTs) in the primary prevention setting, retrospective analyses and reports from the studies in which AF was a pre-specified secondary endpoint have shown a sustained reduction in new-onset AF with ACEIs and ARBs in patients with significant underlying heart disease (e.g. left ventricular dysfunction and hypertrophy), and in the incidence of AF after cardiac surgery in patients treated with statins. In the secondary prevention setting, the results with upstream therapies are significantly less encouraging. Although the results of hypothesis-generating small clinical studies or retrospective analyses in selected patient categories have been positive, larger prospective RCTs have yielded controversial, mostly negative, results. Notably, the controversy exists on whether upstream therapy may impact mortality and major non-fatal cardiovascular events in patients with AF. This has been addressed in retrospective analyses and large prospective RCTs, but the results remain inconclusive pending further reports. This review provides a contemporary evidence-based insight into the role of upstream therapies in primary (Part I) and secondary (Part II) 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.

Pathophysiological mechanisms of atrial fibrillation: a translational appraisal

Atrial fibrillation (AF) is an arrhythmia that can occur as the result of numerous different pathophysiological processes in the atria. Some aspects of the morphological and electrophysiological alterations promoting AF have been studied extensively in animal models. Atrial tachycardia or AF itself shortens atrial refractoriness and causes loss of atrial contractility. Aging, neurohumoral activation, and chronic atrial stretch due to structural heart disease activate a variety of signaling pathways leading to histological changes in the atria including myocyte hypertrophy, fibroblast proliferation, and complex alterations of the extracellular matrix including tissue fibrosis. These changes in electrical, contractile, and structural properties of the atria have been called "atrial remodeling." The resulting electrophysiological substrate is characterized by shortening of atrial refractoriness and reentrant wavelength or by local conduction heterogeneities caused by disruption of electrical interconnections between muscle bundles. Under these conditions, ectopic activity originating from the pulmonary veins or other sites is more likely to occur and to trigger longer episodes of AF. Many of these alterations also occur in patients with or at risk for AF, although the direct demonstration of these mechanisms is sometimes challenging. The diversity of etiological factors and electrophysiological mechanisms promoting AF in humans hampers the development of more effective therapy of AF. This review aims to give a translational overview on the biological basis of atrial remodeling and the proarrhythmic mechanisms involved in the fibrillation process. We pay attention to translation of pathophysiological insights gained from in vitro experiments and animal models to patients. Also, suggestions for future research objectives and therapeutical implications are discussed.

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.

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.

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.

Is there a role for statins in atrial fibrillation?

3-Hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins) are some of the most commonly prescribed drugs in the world. While lipid modification remains the primary function of statins, there has been increasing interest in its potential pleiotropic effects, particularly as an anti-inflammatory agent in its role as an antiarrhythmic. Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and carries with it a significant burden in both morbidity and mortality. Treatment for AF currently involves either rate or rhythm control where both have demonstrable associated risks. Rate control necessitates anticoagulation, which can cause life-threatening bleeding, while rhythm control has a poor side-effect profile that may lead to greater mortality and may not completely eliminate the need for anticoagulation. Considering this pressing need for novel therapeutic interventions in AF, this long overdue systematic review explores the potential role of statins in the treatment and prevention of AF. Physicians, especially cardiologists, need to be aware of the host of currently available literature and, more importantly, need to be stimulated to generate discussion and formulate studies that will help debate the issues under the most erudite standards.

Pleiotropic effects of statins in atrial fibrillation patients: the evidence

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. The understanding of the pathophysiology of AF has changed during the last several decades, and a significant role of inflammation and of the renin-angiotensin-aldosterone system has been postulated both experimentally and clinically. There is emerging evidence of an association between inflammation and AF, and mounting evidence links increased C-reactive protein levels not only to already existing AF but also to the risk of developing future AF. The beneficial effects of statins on AF have been reported in several studies. Several randomized clinical and large observational studies have shown similar result that show the beneficial effect of statins in AF. In clinical studies, statins were considered effective in preventing AF after electrical cardioversion, post-ablation, and after permanent pacemaker and implantable cardioverter defibrillator insertion. The antiarrhythmic mechanisms of statins regarding AF prevention in patients with heart failure are still not clear. Perioperative statin use has been associated with favorable postoperative outcome in both cardiovascular and noncardiovascular conditions. Despite a growing body of evidence that drugs with anti-inflammatory properties such as statins may prevent AF, the observed positive effects of statins on the burden of AF appeared to be independent of their cholesterol-reducing properties. However, further data from large-scale randomized trials are clearly needed.

Statin use is associated with lower risk of atrial fibrillation in women with coronary disease: the HERS trial

OBJECTIVE

To determine the efficacy of statin treatment in atrial fibrillation (AF) prevention in women.

DESIGN

Cohort study using data obtained in the Heart and Estrogen/Progestin Replacement Study (HERS).

SETTING

Secondary analysis of a multicentre, randomised controlled clinical trial.

PATIENTS

2673 Postmenopausal women with coronary disease.

MAIN OUTCOME MEASURES

AF prevalence at baseline and incident AF over a mean follow-up of 4.1 years.

RESULTS

88 Women with AF were identified: 29 at baseline and 59 during follow-up. Women with AF were significantly less likely to be taking a statin at study enrollment than those without AF (22% vs 37%, p = 0.003). Baseline statin use was associated with a 65% lower odds of having AF at baseline after controlling for age, race, history of myocardial infarction or revascularisation and history of heart failure (odds ratio 0.35, 95% confidence interval (CI) 0.13 to 0.93, p = 0.04). The risk of developing AF during the study among those free from AF at baseline, adjusted for the same covariates, was 55% less for those receiving statin treatment (hazard ratio 0.45, 95% CI 0.26 to 0.78, p = 0.004).

CONCLUSIONS

Statin treatment is associated with a lower prevalence and incidence of AF after adjustment for potential confounders in postmenopausal women with coronary disease.

The association between previous statin use and development of atrial fibrillation in patients presenting with acute coronary syndrome

AIMS

To examine the association between statin use and the development of atrial fibrillation (AF) in patients presenting with acute coronary syndrome (ACS).

METHODS

From a total of 1000 patients presenting with ACS 241 were on and 759 were not on statin. An AF episode was accepted as endpoint.

RESULTS

The incidence of AF was less frequent in statin group compared to non-statin group (5% vs 10%, respectively, p=0.01). Independent predictors of AF were left atrial diameter, use of statin, age, hypertension, previous AF and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers.

CONCLUSIONS

In ACS patients, statin treatment was associated with lower incidence of AF.

Effect of statin dose on incidence of atrial fibrillation: data from the Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis in Myocardial Infarction 22 (PROVE IT-TIMI 22) and Aggrastat to Zocor (A to Z) trials

BACKGROUND

Inflammation has been suggested as a factor in the initiation and maintenance of atrial fibrillation (AF). Several observational studies have suggested that statins, presumably through their anti-inflammatory properties, decrease the risk of AF.

METHODS

We analyzed 2 large, randomized trials, PROVE IT-TIMI 22 and phase Z of the A to Z trial, which compared lower- versus higher-intensity statin therapy to evaluate whether higher-intensity statin therapy lowered the risk of AF onset during the 2 years of follow-up. We hypothesized that higher-intensity statin therapy would decrease the risk of AF when compared to lower-intensity statin therapy. From each trial, patients experiencing the onset of AF during follow-up were identified from the adverse event reports.

RESULTS

Neither study showed a decreased AF risk with higher-dose statin. In PROVE IT-TIMI 22, 2.9% versus 3.3% in the high- versus standard-dose statin therapy, respectively, experienced the onset of AF over 2 years (OR 0.86, 95% CI 0.61-1.23, P = .41). In A to Z, rates were 1.6% versus 0.99%, respectively (OR 1.58, 95% CI 0.92-2.70, P = .096). In both trials, C-reactive protein levels (plasma or serum) tended to be higher among patients experiencing the onset of AF.

CONCLUSION

Our randomized comparison among 8659 patients found that higher-dose statin therapy did not reduce the short term incidence of AF among patients after acute coronary syndromes when compared with standard dose statin treatment.