Statin Use before By-Pass Surgery Decreases the Incidence and Shortens the Duration of Postoperative Atrial Fibrillation

Prevention of Atrial Fibrillation After Cardiac Surgery: A Review of Literature and Comparison of Different Treatment Modalities

Atrial fibrillation is the most common arrhythmia to occur after cardiac surgery, with an incidence of 10% to 50%. It is associated with postoperative complications including increased risk of stroke, prolonged hospital stays and increased costs. Despite new insights into the mechanisms of atrial fibrillation, no specific etiologic factor has been identified as the sole perpetrator of the arrhythmia. Current evidence suggests that the pathophysiology of atrial fibrillation in general, as well as after cardiac surgery, is multifactorial. Studies have also shown that new-onset postoperative atrial fibrillation following cardiac surgery is associated with a higher risk of short-term and long-term mortality. Furthermore, it has been demonstrated that prophylactic medical therapy decreases the incidence of postoperative atrial fibrillation after cardiac surgery. Of note, the incidence of postoperative atrial fibrillation has not changed during the last decades despite the numerous preventive strategies and operative techniques proposed, although the perioperative and postoperative care of cardiac patients as such has improved.

Mechanism and prevention of atrial remodeling and their related genes in cardiovascular disorders

Atrial fibrillation (AF) is associated with profound structural and functional changes in the atrium. Inflammation mediated atrial fibrosis is one of the key mechanisms in the pathogenesis of AF. The collagen deposition in extracellular matrix (ECM) is mainly mediated by transforming growth factor β1 (TGF-β1) which promotes AF via controlling smads mediated-collagen gene transcription and regulating the balance of metalloproteinases (MMPs)/ tissue inhibitor of metalloproteinases (TIMPs). Although many processes can alter atrial properties and promote AF, animal models and clinical studies have provided insights into two major forms of atrial remodeling: Atrial tachycardia remodeling (ATR), which occurs with rapid atrial tachyarrhythmia's such as AF and atrial flutter, and atrial structural remodeling (ASR), which is associated with CHF and other fibrosis-promoting conditions. The mechanism of atrial remodeling such as atrial enlargement, ultra structural changes of atrial muscle tissue and myocardial interstitial fibrosis in AF is still unclear. At present, many studies focus on calcium overload, renin angiotensin aldosterone system and transforming growth factor β1, that effect on atrial structural remodeling. Recent experimental studies and clinical investigations have provided structural remodeling is important contributor to the AF. This paper reviews the current understanding of the progresses about mechanism of atrial structural remodeling, and highlights the potential therapeutic approaches aimed at attenuating structural remodeling to prevent AF. Now some recent advancements of this area are reviewed in this paper.

WITHDRAWN: Preoperative statin therapy for patients undergoing cardiac surgery

This review has been withdrawn as authors are unable to complete the updating process.

The editorial group responsible for this previously published document have withdrawn it from publication.

Preoperative statin therapy for patients undergoing cardiac surgery

BACKGROUND

Patients referred to cardiac surgery for cardiovascular disease are at significant risk for the development of major postoperative adverse events despite significant advances in surgical techniques and perioperative care. Statins (5-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitors) have gained a pivotal role in the primary and secondary prevention of coronary artery disease and are thought to improve perioperative outcomes in patients undergoing cardiac surgery. This review is an updated version of a review that was first published in 2012.

OBJECTIVES

To determine the effectiveness of preoperative statin therapy in patients undergoing cardiac surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11), MEDLINE (1950 to November 2013 Week 3), EMBASE (1980 to 3 December 2013 (Week 48)) and the metaRegister of Controlled Trials. Additionally, we searched ongoing trials through the National Research Register, the ClinicalTrials.gov registry and grey literature. We screened online conference indices from relevant scientific meetings (2006 to 2014) to look for eligible trials. We applied no language restrictions.

SELECTION CRITERIA

All randomised controlled trials comparing any statin treatment before cardiac surgery, for any given duration and dose, versus no preoperative statin therapy (standard of care) or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors evaluated trial quality and extracted data from titles and abstracts identified by electronic database searches according to predefined criteria. Accordingly, we retrieved full-text articles of potentially relevant studies that met the inclusion criteria to assess definitive eligibility for inclusion. We reported effect measures as odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 17 randomised controlled studies including a total of 2138 participants undergoing on-pump or off-pump cardiac surgical procedures, and added to this review six studies with 1154 additional participants. Pooled analysis showed that statin treatment before surgery reduced the incidence of postoperative atrial fibrillation (AF) (OR 0.54, 95% CI 0.43 to 0.67; P value < 0.01; 12 studies, 1765 participants) but failed to influence short-term mortality (OR 1.80, 95% CI 0.38 to 8.54; P value = 0.46; two studies, 300 participants) or postoperative stroke (OR 0.70, 95% CI 0.14 to 3.63; P value = 0.67; two studies, 264 participants). In addition, statin therapy was associated with a shorter stay for patients on the intensive care unit (ICU) (WMD -3.19 hours, 95% CI -5.41 to -0.98; nine studies, 721 participants) and in the hospital (WMD -0.48 days, 95% CI -0.78 to -0.19; 11 studies, 1137 participants) when significant heterogeneity was observed. Results showed no reduction in myocardial infarction (OR 0.48, 95% CI 0.21 to 1.13; seven studies, 901 participants) or renal failure (OR 0.57, 95% CI 0.30 to 1.10; five studies, 467 participants) and were not affected by subgroup analysis. Trials investigating this safety endpoint reported no major or minor perioperative side effects of statins.

AUTHORS' CONCLUSIONS

Preoperative statin therapy reduces the odds of postoperative atrial fibrillation (AF) and shortens the patient's stay on the ICU and in the hospital. Statin pretreatment had no influence on perioperative mortality, stroke, myocardial infarction or renal failure, but only two of all included studies assessed mortality. As analysed studies included mainly individuals undergoing myocardial revascularisation, results cannot be extrapolated to patients undergoing other cardiac procedures such as heart valve or aortic surgery.

Atorvastatin Reduces the Incidence of Postoperative Atrial Fibrillation in Statin-Naive Patients Undergoing Isolated Heart Valve Surgery: A Double-Blind, Placebo-Controlled Randomized Trial

BACKGROUND

Atorvastatin has been demonstrated to reduce the incidence of postoperative atrial fibrillation (POAF) in patients undergoing cardiac surgery, but its effect on isolated heart valve surgery is unknown.

METHODS

In a randomized, double-blinded, placebo-controlled trial, 58 patients who underwent isolated heart valve surgery supported by on-pump cardiopulmonary bypass were randomly assigned to receive either placebo (n = 29) or 40 mg of atorvastatin once daily starting 3 days preoperatively and continuing within 5 days postoperatively (n = 29). A continuous monitoring tool and an electrocardiographic Holter monitoring were used for detecting the POAF (Clinical Trial Registration: www.clinicaltrials.gov; Unique Identifier: NTC02084069).

RESULTS

The patients' median age was 49 years, and 67% were female. In all, 6 (21%) and 13 (45%) cases of POAF were observed in the atorvastatin and placebo groups, respectively (P = .050). The duration of AF before re-establishment of sinus rhythm was significantly lower in the atorvastatin group than in the placebo group (median of 70 vs 132 minutes, P = .026). The lengths of intensive care unit and hospital stay were comparable between the groups. The increase in postoperative white blood cell count was significantly lower in the atorvastatin group than in the placebo group (median of 1.5 vs 2.3 × 10(3)/µL, respectively, P = .019). After adjustment, the atorvastatin treatment was associated with a decrease in the risk of developing POAF (odds ratio 0.122, 95% confidence interval 0.027-0.548, P = .006).

CONCLUSION

Perioperative treatment with 40 mg of atorvastatin is useful to decrease the incidence of POAF in the statin-naive patients undergoing isolated heart valve surgery.

Role of inflammation in the initiation and maintenance of atrial fibrillation and the protective effect of atorvastatin in a goat model of aseptic pericarditis

The present study was designed to determine the association between atrial fibrillation (AF) and inflammation in a goat sterile pericarditis model and to assess the effect of atorvastatin, a cholesterol-reducing drug, on AF. A total of 15 adult male goats were randomly divided into control, untreated pericarditis and atorvastatin-treated pericarditis groups. Pericarditis was induced via thoracotomy and atorvastatin was administered orally (60 mg/day) to the goats in the latter group for the duration of the study, commencing 1 week prior to surgery. The levels of high-sensitivity C-reactive protein (hs-CRP), interleukin(IL)-6 and tumor necrosis factor-α (TNF-α) were significantly elevated following surgery in the untreated pericarditis and atorvastatin groups compared with the control group (P<0.05). However, lower levels of hs-CRP, IL-6 and TNF-α were observed in the atorvastatin group compared with the untreated pericarditis group (P<0.05). Additionally, the animals in the atorvastatin-treated pericarditis group had a longer effective refractory period (ERP) and a higher rate adaptation of the ERP compared with those in the untreated pericarditis group (P<0.05). There was a significant negative correlation between the levels of ERP and hs-CRP in the untreated pericarditis group. The inducibility of AF in the left atrium and the duration of AF in the untreated pericarditis and atorvastatin-treated groups increased significantly following surgery (P<0.05). The pericarditis group, however, had a longer duration of AF compared with the atorvastatin group (P<0.05). Thus, inflammation may promote AF by shortening atrial ERP and by reducing the rate adaptation of ERP. These results suggested that atorvastatin can attenuate AF by inhibiting inflammation and may assist in preventing the occurrence and recurrence of AF following cardiac surgery.

Efficiency of postoperative statin treatment for preventing new-onset postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass grafting: A prospective randomized study

OBJECTIVE

Recent studies have demonstrated that preoperative statin therapy reduces the incidence of postoperative atrial fibrillation (AF). The objective of this study was to assess the efficacy of statin therapy started in the early postoperative period for the prevention from new-onset AF after isolated coronary artery bypass grafting (CABG).

METHODS

This prospective and randomized study consisted of 60 consecutive patients who underwent elective isolated CABG. Patients were divided into two groups to examine the influence of statins: those with postoperative statin therapy (statin group, n=30) and those without it (non-statin group, n=30). Patient data were collected and analyzed prospectively. In the statin group, each extubated patient was given 40 mg of atorvastatin per day, starting from an average of 6 hours after the operation.

RESULTS

The overall incidence of postoperative AF was 30%. Postoperative AF occurred in 5 patients (16.7%) in the statin group. This was significantly lower compared with 13 patients (43.3%) in the non-statin group (p=0.049). According to the multivariate analysis, postoperative atorvastatin reduced the risk of postoperative AF by 49% [odds ratio (OR) 0.512, 95% confidence interval (CI) 0.005 to 0.517, p=0.012]. Also, age was an independent predictor of postoperative AF (OR 1.299, 95% CI 1.115 to 1.514, p=0.001).

CONCLUSION

Postoperative statin therapy seems to reduce new-onset AF after isolated CABG in our study.

Serum cholesterol levels and postoperative atrial fibrillation

Background

Post-operative atrial fibrillation is an important complication after coronary bypass surgery. As inflammation and oxidative stress were makedly encountered in the etiology, high cholesterol was also defined to provoke atrial fibrillation. In this present study, the relationship between postoperative atrial fibrillation and preoperative serum lipid levels were evaluated.

Methods

A total of 100 patients, who were operated at the department of Cardiovascular Surgery of our hospital were included to the study analysis. Patients, who had preoperative atrial fibrillation, thyroid dysfunction, or left atrial dilatation (above 4.5 cm) were excluded from the study. Patients were divided into two groups with postoperative atrial fibrillation development (Group I n = 36), and without atrial fibrillation development (Group II n = 64). Preoperative routine blood analyses, ECG, echocardiography were evaluated. Patients were followed for atrial fibrillation development for one month starting from the intensive care unit at the postoperative period. Serum lipid profiles and thyroid function were measured. For homogenization of inflammatory factors and oxidative stress, treatments other than statins, betablockers, calcium channel blockers, aspirin, ACE inhibitors, and ARB were stopped for 10 days. Atrial fibrillation for at least ≥5 minutes in the intensive care unit was accepted as postoperative atrial fibrillation.

Results

Demographic data were similiar between groups (p > 0.05). There was no difference in TC levels between groups, whereas LDL-C levels were statistically lower in patients developing post-operative atrial fibrillation (106.67 ± 28.36 vs 118.75 ± 27.75; P < 0.05).

Conclusion

The more lowered is the LDL-C in the preoperative period, the more reduced risk of postoperative atrial fibrillation development. High levels of LDL-C in the preoperative period could be predictor of atrial fibrillation development in the post operative period.

Carvedilol for prevention of atrial fibrillation after cardiac surgery: a meta-analysis

BACKGROUND

Postoperative atrial fibrillation (POAF) remains the most common complication after cardiac surgery. Current guidelines recommend β-blockers to prevent POAF. Carvedilol is a non-selective β-adrenergic blocker with anti-inflammatory, antioxidant, and multiple cationic channel blocking properties. These unique properties of carvedilol have generated interest in its use as a prophylaxis for POAF.

OBJECTIVE

To investigate the efficacy of carvedilol in preventing POAF.

METHODS

PubMed from the inception to September 2013 was searched for studies assessing the effect of carvedilol on POAF occurrence. Pooled relative risk (RR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models when appropriate. Six comparative trials (three randomized controlled trials and three nonrandomized controlled trials) including 765 participants met the inclusion criteria.

RESULTS

Carvedilol was associated with a significant reduction in POAF (relative risk [RR] 0.49, 95% confidence interval [CI] 0.37 to 0.64, p<0.001). Subgroup analyses yielded similar results. In a subgroup analysis, carvedilol appeared to be superior to metoprolol for the prevention of POAF (RR 0.51, 95% CI 0.37 to 0.70, p<0.001). No evidence of heterogeneity was observed.

CONCLUSIONS

In conclusion, carvedilol may effectively reduce the incidence of POAF in patients undergoing cardiac surgery. It appeared to be superior to metoprolol. A large-scale, well-designed randomized controlled trial is needed to conclusively answer the question regarding the utility of carvedilol in the prevention of POAF.

Inflammation in new-onset atrial fibrillation after cardiac surgery: a systematic review

BACKGROUND

Postoperative new-onset atrial fibrillation (PNAF) is the most common complication following cardiac surgery. The pathogenesis of PNAF is multifactorial. The concept of the postoperative inflammatory response, as a potential underlying mechanism has been extensively studied. This review aims to provide a comprehensive summary of literature relevant to the association between the inflammatory response following cardiac surgery and PNAF.

DESIGN

MEDLINE, EMBASE and the Cochrane Central Register were systematically reviewed by two independent investigators for studies published between January 1980 and May 2012, in which an association between serum markers of inflammation and PNAF was evaluated, or the effect of drugs with anti-inflammatory properties on the risk of PNAF.

RESULTS

Sixty-three studies met selection criteria (39 observational and 24 randomized studies) including 27,363 patients. The mean incidence of PNAF after cardiac surgery was 25·5%. Elevated levels of various inflammatory mediators were associated with PNAF, and the most consistent association was found between white blood cell count and PNAF. Of the drugs with anti-inflammatory properties, statins gave the best protective effect against PNAF, followed by anti-oxidants, steroids and colchicine. Nonsteroidal anti-inflammatory drugs did not prevent PNAF significantly.

CONCLUSION

The postoperative inflammation response may play a role in the pathogenesis of PNAF. However, of the inflammation biomarkers, only elevated white blood cell count reliably predicts PNAF. Pre- and perioperative use of statins and several other drugs with anti-inflammatory properties reduce the incidence of PNAF.

Preoperative statin therapy in cardiac surgery: a meta-analysis of 90,000 patients

The objective of this systematic literature review with meta-analysis was to determine the strength of evidence for a preoperative statin on the reduction of adverse postoperative outcomes in patients undergoing cardiac surgery. Randomized controlled (RCT) and observational trials were searched in online databases that reported about the effects of preoperative statin therapy on major adverse clinical outcomes after cardiac surgery. Analysed outcomes included early all-cause mortality, myocardial infarction, atrial fibrillation (AF), stroke and renal failure using a priori-defined criteria. Effect estimates were calculated and are given as odds ratio (OR) with 95% confidence intervals (95% CI) using fixed- or random-effect models. Literature search of all major databases retrieved 2371 studies. After screening, a total of 54 trials were identified (12 RCT, 42 observational) that reported outcomes of 91 491 cardiac surgery patients with (n = 46 614; 51%) or without (n = 44 877; 49%) preoperative statin therapy. Preoperative statin use resulted in a 0.9% absolute risk (2.6 vs 3.5%) and a 31% odds reduction for early all-cause mortality (OR 0.69; 95% CI 0.59-0.81; P < 0.0001). In addition, statin treatment before surgery was associated with a substantial reduction (P < 0.01) in the postoperative end-points AF (OR 0.71; 95% CI 0.61-0.82), new-onset AF (OR 0.68; 95% CI 0.54-0.85), stroke (OR 0.83; 95% CI 0.74-0.93), stay on intensive care unit (weighted mean difference [WMD] -0.14; 95% CI -0.23 to -0.03; P < 0.01) and in-hospital stay (WMD -0.57; 95% CI -0.76 to -0.38; P < 0.01). No statistical differences were found between groups with regard to myocardial infarction or renal failure. In conclusion, the current systematic review strengthens the evidence that preoperative statin therapy extends substantial clinical benefit to early postoperative outcomes in cardiac surgery patients.

Preoperative statin therapy for patients undergoing cardiac surgery

BACKGROUND

Patients referred to cardiac surgery for cardiovascular disease are at significant risk for the development of post-operative major adverse events despite significant advances in surgical techniques and perioperative care. Statins (HMG-CoA reductase inhibitors) have gained a pivotal role in the primary and secondary prevention of coronary artery disease, and are thought to improve perioperative outcomes in patients undergoing cardiac surgery.

OBJECTIVES

To determine the effectiveness of a preoperative statin therapy in patients undergoing cardiac surgery.

SEARCH METHODS

We searched CENTRAL (Issue 2 of 4, 2010 on The Cochrane Library), MEDLINE (1950 to May, Week 1 2010), EMBASE (1980 to 2010 Week 19), and the metaRegister of Controlled Trials. Additionally, ongoing trials were searched through the National Research Register, the ClinicalTrials.gov registry and grey literature. Conference indices from relevant scientific meetings (2006-2009) were screened online for eligible trials. No language restrictions were applied.

SELECTION CRITERIA

All randomized controlled trials comparing any statin treatment before cardiac surgery, for any given duration and dose, to no preoperative statin therapy (standard of care) or placebo.

DATA COLLECTION AND ANALYSIS

Two authors evaluated trial quality and extracted data from titles and abstracts identified from the electronic database searches according to pre-defined criteria. Accordingly, full text articles of potentially relevant studies that met the inclusion criteria were retrieved to assess definite eligibility for inclusion. Effect measures are reported as odds ratios (OR) or weighted mean difference (WMD) with 95% confidence intervals (95%-CI).

MAIN RESULTS

Eleven randomized controlled studies including a total of 984 participants undergoing on- or off-pump cardiac surgical procedures were identified. Pooled analysis showed that statin pre-treatment before surgery reduced the incidence of post-operative atrial fibrillation (AF) (OR 0.40; 95%-CI: 0.29 to 0.55; p<0.01), but failed to influence short-term mortality (OR 0.98, 95%-CI: 0.14 to 7.10; p=0.98) or post-operative stroke (OR 0.70, 95%-CI: 0.14 to 3.63; p=0.67). In addition, statin therapy was associated with a shorter length of stay of patients on the intensive care unit (ICU) (WMD: -3.39 hours; 95%-CI: -5.77 to -1.01) and in-hospital (WMD: -0.48 days; 95%-CI: -0.85 to -0.11) where significant heterogeneity was observed. There was no reduction in myocardial infarction (OR 0.52; 95%-CI: 0.2. to 1.30) or renal failure (OR 0.41; 95%-CI: 0.15 to 1.12). These results were unaffected after subgroup analysis. No major or minor perioperative statin side-effects were reported from trials investigating this safety endpoint.

AUTHORS' CONCLUSIONS

Preoperative statin therapy reduces the odds of post-operative AF and shortens the stay on the ICU and in the hospital. Statin pretreatment had no influence on perioperative mortality, stroke, myocardial infarction or renal failure. Since analysed studies included mainly patients undergoing myocardial revascularizations the results cannot be extrapolated to patients undergoing other cardiac procedures such as heart valve or aortic surgery.

N-Acetylcysteine supplementation for the prevention of atrial fibrillation after cardiac surgery: a meta-analysis of eight randomized controlled trials

BACKGROUND

Atrial fibrillation is the most common type of arrhythmia after cardiac surgery. An increasing body of evidence demonstrates that oxidative stress plays a pivotal role in the pathophysiology of atrial fibrillation. N-acetylcysteine (NAC) is a free radical scavenger, and may attenuate this pathophysiologic response and reduce the incidence of postoperative AF (POAF). However, it is unclear whether NAC could effectively prevent POAF. Therefore, this meta-analysis aims to assess the efficacy of NAC supplementation on the prevention of POAF.

METHODS

Medline and Embase were systematically reviewed for studies published up to November 2011, in which NAC was compared with controls for adult patients undergoing cardiac surgery. Outcome measures comprised the incidence of POAF and hospital length of stay (LOS). The meta-analysis was performed with the fixed-effect model or random-effect model according to the heterogeneity.

RESULTS

Eight randomized trials incorporating 578 patients provided the best evidence and were included in this meta-analysis. NAC supplementation significantly reduced the incidence of POAF (OR 0.62, 95% CI 0.41 to 0.93; P = 0.021) compared with controls, but had no effect on LOS (WMD -0.07, 95% CI -0.42 to 0.28; P = 0.703).

CONCLUSIONS

The prophylactic NAC supplementation may effectively reduce the incidence of POAF. However, the overall quality of current studies is poor and further research should focus on adequately powered randomized controlled trials with POAF incidence as a primary outcome measure.

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.

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.

Preoperative Statin use is not Associated with a Reduced Risk of Atrial Fibrillation After Cardiac Surgery

Introduction: Postoperative atrial fibrillation (POAF) is prevalent after cardiac surgery and associated with significant morbidity and costs. Statins are commonly used in this population and may be a preventative strategy for PAOF. We wished to examine the effect of preoperative statin use on the risk of POAF after cardiac surgery. Methods: A retrospective, observational study was conducted using data from 489 adult patients who underwent cardiac surgery at a single institution. Univariate analyses and unconditional logistic regression were used to determine the impact of preoperative statin use on the probability of developing POAF, while controlling for the baseline risk of POAF and the use of amiodarone prophylaxis (AMP). A baseline risk index was calculated for each patient using a previously validated model. Patients with chronic atrial fibrillation or missing data were excluded. Results: Mean patient age was 63 (SD=13) years, 73% were male, 68% underwent isolated coronary artery bypass grafting, 16% underwent isolated valve surgery, with 13% underwent combined CABG and valve surgeries, and 3% underwent other forms of cardiac surgery. POAF occurred in 27% of patients receiving statins and 24% of those not receiving statins (p=0.3792). After controlling for baseline risk of POAF and the use of AMP, we found that preoperative statins were not associated with reductions in POAF (OR=1.19, 95%CI=0.782-1.822, p=0.4118). Conclusions: Multiple factors impact the development of POAF after cardiac surgery including patient demographics, comorbidities, surgical type, and concomitant medications. In this study, after adjustment for these factors the preoperative use of statins did not significantly influence the development of POAF.

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.

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.

Statins Do Not Reduce Atrial Fibrillation After Cardiac Valvular Surgery: A Single Centre Observational Study

INTRODUCTION: Statins may theoretically reduce postoperative atrial fibrillation (AF) in patients after cardiac valvular surgery due to preservation of endothelial function and anti-ischaemic, anti-inflammatory and anti-remodelling effects. METHODS: Two hundred seventy-two patients who underwent cardiac workup and subsequently cardiac valvular surgery without AF and concomitant coronary artery bypass grafting (CABG) at our hospital were selected. Preoperative drug use and postoperative AF were recorded. AF was defined as any episode of AF longer than 10 s. In addition, results from echocardiography and blood samples were retrieved. RESULTS: BASELINE CHARACTERISTICS WERE AS FOLLOWS: mean age was 65 ± 11 years, 142 (52%) patients were male, 189 (70%) had undergone aortic valve surgery and the mean left ventricular ejection fraction was 57 ± 12%. Statins were used by 79 patients (29%). Statin users, more often, had a prior percutaneous coronary intervention (25% vs 9%, p < 0.001) or CABG (24% vs 4%, p < 0.001), diabetes mellitus (22% vs 5%, p < 0.001) and more often used β-blockers (51% vs 24%, p < 0.001). Patients in the non-statin group more often had surgery on more than one valve (10% vs 3%, p = 0.043) and had a higher cholesterol level (222 ± 48 vs 190 ± 43 mg/dl, p < 0.001). Postoperative AF occurred in 54% (43/79) of the patients with and in 55% (106/193) of the patients without statins (p = 0.941). There was also no difference in the timing of onset of AF or duration of hospital stay. CONCLUSION: In this observational study, statin use was not associated with a reduced incidence of AF in patients after cardiac valvular surgery.

Review: Beyond the Guidelines: New and Novel Agents for the Prevention of Atrial Fibrillation After Cardiothoracic Surgery

Postoperative atrial fibrillation (POAF), a common complication of cardiac surgery, can increase the morbidity and mortality, as well as the costs of the surgery being preformed. Guidelines recommend the use of β-blockers, amiodarone, or sotalol to decrease the risk of experiencing POAF. However, none of these agents fully protect the patient from POAF, thus newer agents are needed to be used in combination with them. Many different agents have been studied to fit this role and may be grouped into 2 categories: agents with antiarrhythmic activity such as magnesium and polyunsaturated fatty acids and agents with anti-inflammatory activity such as statins and free radical scavengers. Most of these novel agents have been studied in a wide variety of trials; however, some clearly have more effect than others. Although none of these newer agents have the data required to make blanket recommendations for use at this point, given the safety profile and low costs of some, many continue to be evaluated in randomized-controlled trials.

Perioperative statin use: an update

HMG CoA reductase inhibitors (statins) are a proven modality to reduce serum cholesterol and have been shown to reduce morbidity and mortality in cardiovascular patients. Statins have also demonstrated improvements in postoperative outcomes among patients taking them in the perioperative period. Many of the studies are limited to select patient populations and/or select surgeries. This review will give an overview of the pharmacology of statins, summarize the mechanisms of the beneficial effects of statins, and provide an overview of evidence in the use of statins in the perioperative period.

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.

Preoperative high-dose atorvastatin for prevention of atrial fibrillation after cardiac surgery: a randomized controlled trial

OBJECTIVE

The preventative effect of statins on postoperative atrial fibrillation has been hypothesized. However, all studies to date have examined patients who did not receive statins before their further allocation to treatment or no treatment. Because guidelines recommend the routine use of statins in patients with coronary artery disease, we set out to examine the effect of intensive statin pretreatment versus continuation of usual statin dose on atrial fibrillation after cardiac surgery.

METHODS

Patients receiving routine statin treatment and undergoing coronary artery bypass surgery or aortic valve replacement with no history of atrial fibrillation or antiarrhythmic medication were randomized to receive atorvastatin 80 mg or atorvastatin 10 mg for 7 days before surgery in a single-blind fashion. The primary end point was the development of postoperative atrial fibrillation during hospital stay.

RESULTS

A total of 104 consecutive patients were included. Postoperative atrial fibrillation occurred in 33 patients (32.4%). No significant differences were found in demographics, medical history, or intraoperative variables between treatment groups, with the exception of higher rate of β-blocker use in the atorvastatin 10 mg group (75% vs 53%, P = .002) and previous myocardial infarction (62% vs 42%, P = .049). The incidence of postoperative atrial fibrillation was lower in the atorvastatin 80 mg group when compared with the atorvastatin 10 mg group, but this difference did not reach statistical significance (29% vs 36%, P = .43).

CONCLUSIONS

High-dose atorvastatin for 7 days before cardiac surgery conferred a nonsignificant reduction in postoperative atrial fibrillation when compared with a low-dose regimen. A larger study would be necessary to confirm the beneficial effect of high-dose statins in this setting.

Atorvastatin for reduction of myocardial dysrhythmia after cardiac surgery study

Evaluation of: Patti G, Chello M, Candura D et al.: Atorvastatin for Reduction of MYocardial Dysrhythmia After cardiac surgery (ARMYDA-3) study. Circulation 114, 1455-1461 (2006). The Atorvastatin for Reduction of MYocardial Dysrhythmia After cardiac surgery study evaluated the efficacy of atorvastatin 40 mg/day compared with placebo, adminstered 1 week prior to surgery in preventing post-operative atrial fibrillation (AF). The rate of post-operative AF and mean post-operative hospital stay was significantly lower in the atorvastatin group compared with the placebo group. The incidence of the composite end point at 1 month was similar in both groups. This study supports the initiation of atorvastatin in patients undergoing cardiac surgery to reduce the rate of post-operative AF and the duration of hospital stay. Future studies will be required to assess whether this beneficial effect of atorvastatin is demonstrated by all statins and whether it can be extended to the wider population of patients with AF.

Dose dependent effect of statins on postoperative atrial fibrillation after cardiac surgery among patients treated with beta blockers

Background

Previous studies on the effects of Statins in preventing atrial fibrillation (AF) after cardiac surgery have shown conflicting results. Whether statins prevent AF in patients treated with postoperative beta blockers and whether the statin-effect is dose related are unknown.

Methods

We retrospectively studied 1936 consecutive patients who underwent coronary artery bypass graft (CABG) (n = 1493) or valve surgery (n = 443) at the Minneapolis Veterans Affairs Medical Center. All patients were in sinus rhythm before the surgery. Postoperative beta blockers were administered routinely (92% within 24 hours postoperatively).

Results

Mean age was 66+10 years and 68% of the patients were taking Statins. Postoperative AF occurred in 588 (30%) patients and led to longer length of stay in the intensive care unit versus those without AF (5.1+7.6 days versus 2.5+2.3 days, p < 0.0001). Patients with a past history of AF had a 5 times higher risk of postoperative AF (odds ratio 5.1; 95% confidence interval 3.4 to 7.7; p < 0.0001). AF occurred in 31% of patients taking statins versus 29% of the others (p = 0.49). In multivariable analysis, statins were not associated with AF (odds ratio (OR) 0.93, 95% confidence interval (CI) 0.7 to 1.2; p = 0.59). However, in a subgroup analysis, the patients treated with Simvastatin >20 mg daily had a 36% reduction in the risk of postoperative AF (OR 0.64, 95% CI 0.43 to 0.6; p = 0.03) in comparison to those taking lower dosages.

Conclusion

Among cardiac surgery patients treated with postoperative beta blockers Statin treatment reduces the incidence of postoperative AF when used at higher dosages

Upstream therapy of atrial fibrillation

Failure of current pharmacological therapy for atrial fibrillation in maintaining sinus rhythm may be due to structural atrial remodeling caused by inflammation and fibrosis. Upstream therapy that interferes in the structural remodeling process may be effective in maintaining sinus rhythm. This article reviews upstream therapy in atrial fibrillation. Various prospective and retrospective studies demonstrate that upstream therapy, consisting of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, fish oils, glucocorticoids, or moderate physical activity, is associated with a reduced incidence of new-onset atrial fibrillation (i.e., primary prevention) and with a reduced recurrence of atrial fibrillation (i.e., secondary prevention). Larger clinical trials are required to further elucidate the position of upstream therapy in the primary and secondary prevention of atrial fibrillation.

Pharmacological therapy for atrial fibrillation: current options and new agents

Atrial fibrillation is the most commonly encountered cardiac arrhythmia and is directly or indirectly responsible for considerable mortality, morbidity and health care burden. The available medical therapy is limited by marginal efficacy, end-organ toxicity, as well as the potential for undesired ventricular proarrhythmia. Elucidation of the potential mechanisms that underlie the development of atrial fibrillation may provide new targets for drugs that circumvent the problems associated with current medical options. This review focuses on the current and potential future pharmacological agents directed at rhythm control and maintenance of sinus rhythm.

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.