Statins and postoperative risk of atrial fibrillation following coronary artery bypass grafting

Atrial fibrillation following cardiac surgery: clinical features and preventative strategies

Atrial fibrillation (AF) is a common complication of cardiac surgery, with an increasing incidence. Post-operative AF results in many complications and increased healthcare resources. Despite substantial interest in the prediction and prevention of post-operative AF, as well as guidelines for the management of this common arrhythmia, there is still some uncertainty about appropriate risk stratification and management. The aim of this review article is to provide an overview of clinical predictive features for the development of AF following cardiac surgery and suitable preventive measures, using both antiarrhythmic and non-antiarrhythmic strategies.

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.

The impact of statin use on atrial fibrillation

The aim of the present systematic review is to present an overview of the evidence linking atrial fibrillation (AF), inflammation and oxidative stress, with emphasis on the potential of statins to decrease the incidence of different types of AF, including new-onset AF, after electrical cardioversion (EC) and after cardiac surgery. Observational and clinical trials have studied the impact of statin therapy on new-onset, post-EC or postoperative AF. Data from different observational trials have shown that treatment with statins significantly reduces the incidence of new-onset AF in the primary and secondary prevention. The data are insufficient to recommend the use of statins before EC. Finally, perioperative statin therapy may represent an important non-antiarrhythmic adjunctive therapeutic strategy for the prevention of postoperative AF.

Milrinone use is associated with postoperative atrial fibrillation after cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (AF), a frequent complication after cardiac surgery, causes morbidity and prolongs hospitalization. Inotropic drugs are commonly used perioperatively to support ventricular function. This study tested the hypothesis that the use of inotropic drugs is associated with postoperative AF.

METHODS AND RESULTS

We evaluated perioperative risk factors in 232 patients who underwent elective cardiac surgery. All patients were in sinus rhythm at surgery. Sixty-seven patients (28.9%) developed AF a mean of 2.9+/-2.1 days after surgery. Patients who developed AF stayed in the hospital longer (P<0.001) and were more likely to die (P=0.02). Milrinone use was associated with an increased risk of postoperative AF (58.2% versus 26.1% in nonusers; P<0.001). Older age (63.4+/-10.7 versus 56.7+/-12.3 years; P<0.001), hypertension (P=0.04), lower preoperative ejection fraction (P=0.03), mitral valve surgery (P=0.02), right ventricular dysfunction (P=0.03), and higher mean pulmonary artery pressure (27.1+/-9.3 versus 21.8+/-7.5 mm Hg; P=0.001) also were associated with postoperative AF. In multivariable logistic regression, age (P<0.001), ejection fraction (P=0.02), and milrinone use (odds ratio, 4.86; 95% confidence interval, 2.31 to 10.25; P<0.001) independently predicted postoperative AF. When only data from patients with pulmonary artery catheters were analyzed and pulmonary artery pressure was included in the model, age, milrinone use (odds ratio, 4.45; 95% confidence interval, 2.01 to 9.84; P<0.001), and higher pulmonary artery pressure (P=0.02) were associated with an increased risk of postoperative AF. Adding other potential confounders or stratifying analysis by mitral valve surgery did not change the association of milrinone use with postoperative AF.

CONCLUSIONS

Milrinone use is an independent risk factor for postoperative AF after elective cardiac surgery.

Antiarrhythmic effects of statins in heart failure

In vitro heart failure models indicate that statins may be antiarrhythmic, but the mechanisms by which statins are antiarrhythmic are not completely understood. Several retrospective and post hoc analysis studies also indicate that statins can be antiarrhythmic in heart failure populations, but this was not confirmed by a recent large prospective randomized controlled clinical trial. Ongoing and future clinical trials will likely resolve the discrepancies between studies and further the understanding of how pleiotropic properties of statins can be antiarrhythmic in patients who have heart failure.

Effects of atorvastatin 80 mg daily on indices of matrix remodelling in 'high-risk' patients with ischemic heart disease

Recent evidence suggests that higher doses of statins could improve clinical outcomes compared to conventional doses, but whether this benefit is due to "additional" pleiotropic effects is uncertain. We tested the hypothesis that atorvastatin 80 mg/day would have beneficial effects on indices of matrix remodelling (matrix metalloproteinase-1, MMP-1, and its tissue inhibitor, TIMP-1) in high-risk cardiovascular disease. We studied 27 "high-risk" patients (inclusion criteria: severe triple vessel but rejected for by-pass for extensive coronary disease, severe effort angina after coronary artery by-pass and premature coronary disease with > or =3 risk factors) with an abnormal lipid profile despite atorvastatin 40 mg/day, at baseline and at 3 months after increasing the statin dose to 80 mg/day. Baseline results in patients were compared to 22 healthy controls. At baseline, patients had lower levels of MMP-1 compared to controls. When atorvastatin was increased to 80 mg/day, significant reduction in LDL-cholesterol was observed, whereas MMP-1 and TIMP-1 levels were increased. These, despite of atorvastatin 40 mg daily, 'high-risk' patients still demonstrated abnormal extracellular remodelling indices. Doubling the dose of atorvastatin resulted in significant improvement in extracellular remodelling indices.

Prevention and management of perioperative arrhythmias in the thoracic surgical population

Although bradyarrhythmias or malignant ventricular tachyarrhythmias have been reported in less than 1% of patients following noncardiac surgery, rapid atrial arrhythmias more frequently affect the elderly who undergo thoracic operations. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of postoperative atrial arrhythmias. It discusses new risk factors and a prediction rule for postthoracotomy atrial fibrillation (AF), reviews prophylaxis and acute therapeutic interventions for postthoracotomy AF, and highlights the most recent recommendations of the American Heart Association Task Force on the management of patients who have AF with emphasis on preventing thromboembolic events.

The effects of atorvastatin on the occurrence of postoperative atrial fibrillation after off-pump coronary artery bypass grafting surgery

BACKGROUND

Atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery is still the most common arrhythmic complication. This study evaluated whether pretreatment with atorvastatin protects against AF after off-pump CABG.

METHODS

One hundred twenty-four patients without a history of AF or previous statin use, who were scheduled to undergo elective off-pump CABG, were enrolled. Patients were randomized to control group (n = 62) or to atorvastatin group (n = 62) who were administered atorvastatin 20 mg/d for 3 days before the surgery. Primary outcome was the incidence of postoperative AF. Secondary outcomes were major adverse cardiac and cerebrovascular events, persistent AF at 1 month, and identification of the markers to predict inhospital postoperative AF.

RESULTS

The incidence of AF was significantly lower in the atorvastatin group than in the control group (13% vs 27%, P = .04). The incidence of major adverse cardiac and cerebrovascular events and persistent AF at 1 month was similar in comparisons between the groups. Postoperative peak N-terminal pro-brain natriuretic peptide levels were significantly higher in the patients with AF (P = .03). Multivariate analysis identified pretreatment with atorvastatin as an independent factor associated with a significant reduction in postoperative AF (odds ratio 0.34, P = .04). Higher postoperative peak N-terminus pro-B-type natriuretic peptide levels were associated with the development of postoperative AF (odds ratio 1.02 per 100 pg/mL, P = .03).

CONCLUSIONS

Pretreatment with atorvastatin significantly reduced the occurrence of postoperative AF after off-pump CABG.

Atorvastatin prevents atrial fibrillation in patients with bradyarrhythmias and implantation of an atrial-based or dual-chamber pacemaker: a prospective randomized trial

BACKGROUND

Increasing evidence suggests that atrial fibrillation (AF) is an inflammatory disease. Statins is an anti-inflammatory agent. The present study was conducted to test the efficacy of atorvastatin in preventing paroxysmal AF or atrial high rate episodes (AHEs) in patients with bradyarrhythmias and implantation of an atrial-based or dual-chamber pacemaker.

METHODS

The effect of atorvastatin on time to the first attack of AF or AHE (> or =180 per minute and > or =1 or 10 minutes), which was accurately detected by pacemaker interrogation, was evaluated in an open-label prospective randomized design for 1 year of follow-up.

RESULTS

Fifty-two patients (23 males, 70 +/- 13 years old) were randomized to the statin group (atorvastatin 20 mg/d) and 54 (25 males, 72 +/- 13 years old) to the nonstatin group. Event-free survivals from AHE > or =1 minute were not significantly different between the 2 groups (log-rank P = .410). However, patients in the nonstatin group were more likely to develop AHE > or =10 minutes than those in the statin group (log-rank P = .028). Atrial high rate episode > or =10 minutes occurred in 3 (5.8%) of 51 patients in the statin group after 1 year of follow-up, and 10 (19.2%) of 52 patients (odds ratio 0.26, P = .041) in the nonstatin group. The mean left atrial volume of the statin group was significantly lower than that of the nonstatin group at the end of follow-up (39.7 +/- 1.7 vs 43.7 +/- 1.9 mL, P < .0001).

CONCLUSIONS

The present study demonstrated the efficacy of atorvastatin in preventing significant AF (> or =10 minutes) and left atrial enlargement in patients with bradyarrhythmias and implantation of a pacemaker.

Impact of preoperative statin therapy on adverse postoperative outcomes in patients undergoing cardiac surgery: a meta-analysis of over 30,000 patients

AIMS

To determine the strength of evidence for preoperative statin use for prevention of adverse postoperative outcomes in patients undergoing cardiac surgery.

METHODS AND RESULTS

After literature search in major databases, 19 studies were identified [three RCT (randomized prospective clinical trials), 16 observational] that reported outcomes of 31 725 cardiac surgery patients with (n = 17 201; 54%) or without (n = 14 524; 46%) preoperative statin therapy. Outcomes that were analysed included early all-cause mortality (30-day mortality), myocardial infarction (MI), atrial fibrillation (AF), stroke and renal failure. Odds ratio (OR) with 95% confidence intervals (95%CI) were reported using fixed or random effect models and publication bias was assessed. Preoperative statin therapy resulted in a 1.5% absolute risk reduction (2.2 vs. 3.7%; P < 0.0001) and 43% odds reduction for early all-cause mortality (OR 0.57; 95%CI: 0.49-0.67). A significant reduction (P < 0.01) in statin pretreated patients was also observed for AF (24.9 vs. 29.3%; OR 0.67, 95%CI: 0.51-0.88), stroke (2.1 vs. 2.9%, OR 0.74, 95%CI: 0.60-0.91), but not for MI (OR 1.11; 95%CI: 0.93-1.33) or renal failure (OR 0.78, 95%CI: 0.46-1.31). Funnel plot and Egger's regression analysis (P = 0.60) excluded relevant publication bias.

CONCLUSION

Our meta-analysis provides evidence that preoperative statin therapy exerts substantial clinical benefit on early postoperative adverse outcomes in cardiac surgery patients, but underscores the need for RCT trials.

Dose-related effect of statins on atrial fibrillation after cardiac surgery

BACKGROUND

Atrial fibrillation (AF) is the most common heart rhythm abnormality after cardiac surgery. It increases morbidity and prolongs hospital stay. A role for statins in the prevention of AF has been suggested. We hypothesized that the incidence of postoperative AF due to statin therapy is dose-related.

METHODS

A retrospective study of 680 consecutive patients undergoing coronary bypass graft surgery and/or aortic valve replacement was done. Excluded were 57 patients (8.4%) with history of AF, permanent pacemakers, and those receiving antiarrhythmic medication. Preoperative statin treatment and occurrence of postoperative AF were examined using propensity score matching to adjust for differences in patient characteristics between the statin and no-statin groups.

RESULTS

The cohort comprised 623 patients. The statin group had a 27.1% incidence of postoperative AF vs 38.3% in the no-statin group (adjusted odds ratio [OR], 2.00; 95% confidence interval, 1.24 to 3.24; p = 0.004). Simvastatin (40 mg) and atorvastatin (40 mg) demonstrated the greatest effect on postoperative AF at 15.6% and 21.2%, respectively, vs no statins (respective adjusted ORs, 3.89 [p < 0.0001] and 2.76 [p = 0.012]). Intermediate-dose (20 mg) statins were also effective against AF, at 24.4% for simvastatin (adjusted OR, 2.32; p = 0.004) and 26.4% for atorvastatin (adjusted OR, 1.99, p = 0.047). Low-dose statins, simvastatin or atorvastatin (10 mg), did not influence postoperative AF.

CONCLUSIONS

Statin treatment may reduce the incidence of AF after cardiac surgery. Higher-dose statins have the greatest preventative effect, whereas low-dose statins do not influence postoperative AF.

Comparison of the efficacy of metoprolol and carvedilol for preventing atrial fibrillation after coronary bypass surgery

BACKGROUND

Atrial fibrillation (AF) occurs frequently after coronary artery bypass grafting (CABG) and often results in prolonged postsurgical hospital stays and increased mortality and morbidity. Beta blockers are known to prevent postoperative AF. In this prospective study, we investigated the efficacy of carvedilol compared with metoprolol succinate in preventing postoperative AF.

METHODS

Subjects included 110 patients (31 women, 79 men; mean age, 60+/-10 years, range, 39-82 years) who had undergone CABG. Patients were randomized to receive either metoprolol or carvedilol, and all patients received the drugs 3 days prior to surgery. Metoprolol was started at 50 mg twice daily and carvedilol was started at 12.5 mg twice daily. The doses were titrated according to the patients' hemodynamic responses. All patients were monitored for 3 days after the surgery.

RESULTS

Of the 110 patients, 55 (50%) were treated with metoprolol succinate, and 55 (50%) were treated with carvedilol. Baseline characteristics and operative data of the patients did not differ between groups. During follow-up, 20 patients (36%) in the metoprolol group and 9 patients (16%) in the carvedilol group developed AF (P=0.029). Multiple stepwise logistic regression analysis showed that metoprolol use, older age, and impaired left ventricular ejection fraction were independent risk factors for developing AF, and carvedilol use was found to be independently related to sinus rhythm maintenance after CABG (P=0.02).

CONCLUSIONS

These results show that carvedilol is superior to metoprolol in decreasing development of early postoperative AF.

Non-antiarrhythmic medications for atrial fibrillation: from bench to clinical practice

Many treatment modalities have been developed over the years for the management of atrial fibrillation (AF). While they are still considered the first line of treatment for suppression of AF, antiarrhythmics often lead to treatment failure, complications and undesired consequences. Pulmonary vein ablation is an invasive procedure which is not always curative. Recently, there have been a variety of studies reporting the potential antiarrhythmic effects of various nonantiarrhythmic agents. This paper aims to provide a comprehensive review of the findings reported thus far about the antiarrhythmic effects of agents which are not antiarrhythmic drugs themselves, but which have been found to offer promise in the prevention and treatment of AF.

Preoperative statin therapy is not associated with a decrease in the incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery

BACKGROUND

Atrial fibrillation (AF) after cardiac surgery is associated with significant morbidity. We investigated whether preoperative statin therapy was associated with decreased incidence of postoperative AF in patients undergoing cardiac surgery, including isolated valve surgery and patients with low ejection fraction (EF).

METHODS

A retrospective study of consecutive patients without history of AF (n = 4044) who underwent cardiac surgeries at St. Luke's Episcopal Hospital (Houston, TX), from January 1, 2003, through April 30, 2006, was conducted. Postoperative AF was assessed by continuous telemetry monitoring during hospitalization for cardiac surgery.

RESULTS

A total of 2096 patients (52%) received preoperative statins. Atrial fibrillation occurred in 1270 patients (31.4% in both the statin and nonstatin groups). In multivariate regression analysis, age >65 years, history of valvular heart disease, rheumatic disease, pulmonary disease, and New York Heart Association class III/IV were independent predictors of increased risk, whereas female sex was associated with decreased risk. Preoperative statin therapy was not associated with decreased risk in the entire cohort (odds ratio [OR] 1.13, 95% confidence interval [CI] 0.98-1.31) or in subgroups undergoing isolated coronary artery bypass grafting (OR 1.16, 95% CI 0.97-1.43), isolated valve surgery (OR 1.09, 95% CI 0.81-1.46), or both (OR 1.09, 95% CI 0.72-1.65), or the subgroup with EF <35% (OR 1.23, 95% CI 0.84-1.82). After propensity score analysis (n = 867 patients in each group), preoperative statin therapy was not associated with decreased AF incidence (OR 1.14, 95% CI 0.92-1.41).

CONCLUSIONS

Preoperative statin therapy was not associated with decreased incidence of postoperative AF in patients undergoing cardiac surgery, including patients with low EF.

Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning

Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.

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.

Potential Use of Statins to Prevent Atrial Fibrillation After Coronary Artery Bypass Surgery

Objective:

To review the published literature evaluating the effectiveness of statin therapy for preventing postoperative atrial fibrillation (POAF) after coronary artery bypass graft (CABG) surgery,

Data Sources:

A MEDLINE search was performed (1950–October 2007) using the search terms statins, HMG-CoA reductase inhibitors, coronary artery bypass graft, cardiac surgery, and atrial fibrillation,

Study Selection and Data Extraction:

All articles published in English describing or evaluating the use of statins in humans to prevent atrial fibrillation (AF) were included. Additional pertinent articles were identified from reference lists.

Data Synthesis:

POAF is a common complication following CABG surgery that is associated with significant morbidity. Current preventive strategies include the use of β-blockers and antiarrhythmic drugs such as amiodarono and Sotalol. Accumulating evidence suggests that statins may also reduce the risk of POAF. Numerous studies in nonsurgical cardiovascular patients have found reduced rates of AF with statins. In patients who have undergone CABG, several observational studies have also documented benefit. One randomized controlled trial reported a significant reduction in the risk of POAF and reduced length of hospital stay in patients given preoperative atorvastatin beginning 7 days before surgery. Ongoing research suggests that statins may reduce the risk of AF through pleiotropic effects independent of cholesterol lowering such as reductions in inflammation, oxidative damage, neurohormonal activation, and thrombosis.

Conclusions:

While the current evidence evaluating the use of statins to prevent POAF is encouraging, definitive conclusions cannot be drawn. However, because statins are widely used in cardiac patients for other indications and are not associated with the risks inherent to antiarrhythmic drugs, their value as an adjunct to current preventive strategies (or POAF deserves further study. Additional research is needed to examine the effectiveness of statins in risk-stratified patients undergoing CABG surgery and the impact on patient outcomes and attributed costs.

Effect of statins on collagen type I degradation in patients with coronary artery disease and atrial fibrillation

The present study was undertaken to assess the effect of statins on collagen type I degradation and C-reactive protein in patients with coronary artery disease and atrial fibrillation. One hundred six patients with coronary artery disease and atrial fibrillation were studied: 40 (36 men, mean age 72 +/- 8 years) treated with a statin and 66 (48 men, mean age 74 +/- 9 years) not treated with a statin. Serum concentrations of carboxy-terminal telopeptide of collagen type I, an index of collagen type I degradation, and high-sensitivity C-reactive protein were measured in all patients. Carboxy-terminal telopeptide of collagen type I levels were significantly higher (p <0.001) in statin-treated patients (0.64 ng/ml, 95% confidence interval [CI] 0.57 to 0.71) compared with nonstatin-treated patients (0.38 ng/ml, 95% CI 0.31 to 0.44). These changes were independent of cholesterol levels (before or after therapy). Statin-treated patients had significantly lower (p <0.001) C-reactive protein levels (0.25 mg/dl, 95% CI 0.23 to 0.28) compared to statin nonusers (1.1 mg/dl, 95% CI 0.92 to 1.25). In conclusion, this study suggests that therapy with statins in patients with coronary artery disease and atrial fibrillation is associated with an increase in collagen degradation and an attenuation of inflammation, independently of cholesterol lowering.

Drug therapy for atrial fibrillation

Atrial fibrillation (AF) is the most frequently diagnosed arrhythmia. Prevalence increases with age, and the overall incidence is expected to increase as the population continues to age. Choice of pharmacologic therapy for atrial fibrillation depends on whether or not the goal of treatment is maintaining sinus rhythm or tolerating atrial fibrillation with adequate control of ventricular rates. New antiarrhythmic drugs are being tested in clinical trials. Drugs that target remodeling and inflammation are being tested for their use as prevention of AF or as adjunctive therapy.

Observational Study on the Beneficial Effect of Preoperative Statins in Reducing Atrial Fibrillation After Coronary Surgery

BACKGROUND

Recent evidence supports the important role of inflammation in atrial fibrillation (AF) after coronary artery bypass grafting (CABG) and there is growing evidence that statin has cardiac antiarrhythmic effects. The aim of this study was to assess the efficacy of preoperative statins in preventing AF after CABG in a longitudinal observational study.

METHODS

Over a two-year period, 405 consecutive patients underwent isolated CABG procedures. Univariate analysis was performed exploring the relationship regarding statin use and AF development. A propensity score for treatment with statins was obtained from core patient characteristics. The role of statin therapy on postoperative AF was assessed by means of a conditional logistic model, while stratifying on the quintiles of the propensity score. All analysis was performed retrospectively.

RESULTS

Postoperative AF occurred in 29.5% of the patients with preoperative statin therapy compared with 40.9% of those patients without it (p = 0.021). No statistical differences among development of AF and type, dose, or duration of preoperative statin therapy were observed. Preoperative statins were associated with a 42% reduction in risk of AF development after CABG surgery (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.37 to 0.91, p = 0.017, while stratifying on the propensity score). No different effect of statins on AF was observed with respect to age groups (< or = 70 and > 70 years) (interaction p = 0.711).

CONCLUSIONS

Preoperative statins may reduce postoperative AF after CABG. Patients undergoing elective revascularization may benefit from a preventive statin approach.

New antiarrhythmic treatment of atrial fibrillation

Antiarrhythmic pharmaceutical development for the treatment of atrial fibrillation (AF) is moving in several directions. The efficacy of existing drugs, such as carvedilol, for rate control and, possibly, suppression of AF, is more appreciated. Efforts are being made to modify existing agents, such as amiodarone, in an attempt to ameliorate safety and adverse effect concerns. This has resulted in promising data from the deiodinated amiodarone analog, dronedarone, and further work with celivarone and ATI-2042. In an attempt to minimize ventricular proarrhythmia, atrial selective drugs, such as intravenous vernakalant, have demonstrated efficacy in terminating AF in addition to promising data in suppression recurrences when used orally. Several other atrial selective drugs are being developed by multiple manufacturers. Other novel therapeutic mechanisms, such as drugs that enhance GAP junction conduction, are being developed to achieve more effective drug therapy than is offered by existing compounds. Finally, nonantiarrhythmic drugs, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, high-mobility group coenzyme A enzyme inhibitors and omega-3 fatty acids/fish oil, appear to have a role in suppressing AF in certain patient subtypes. Future studies will clarify the role of these drugs in treating AF.

Impact of ramipril on the incidence of atrial fibrillation: results of the Heart Outcomes Prevention Evaluation study

OBJECTIVES

We evaluated the effect of angiotensin-converting enzyme (ACE) inhibitor ramipril on the incidence of atrial fibrillation (AF) in patients enrolled in the Heart Outcomes Prevention Evaluation trial.

BACKGROUND

Atrial fibrillation is the most common arrhythmia affecting the general population and is associated with increased morbidity and mortality. Retrospective secondary analyses of some of the large trials of ACE inhibitors have suggested that ACE inhibitors may prevent AF.

METHODS

We evaluated the occurrence of AF by reviewing the electrocardiogram tracings at entry, at 2 years, and at the end of the study, as well as hospitalizations among 8335 high-risk participants from the Heart Outcomes Prevention Evaluation study, > or = 55 years, without known heart failure or left ventricular (LV) systolic dysfunction and followed for a median period of 4.5 years. We compared the impact of ramipril and matched placebo on occurrence of AF. The results were compared to similar trials.

RESULTS

Over the 4.5 years follow-up, the incidence of new AF was low (2.1%, 177/8335), and ramipril did not significantly reduce the rate of new AF compared with placebo (86/4291 [2.0%] vs 91/4044 [2.2%]) with an odds ratio of 0.92 (95% confidence interval, 0.68-1.24; P = .57). These results added to the previous ACE inhibitor trials (excluding trials in patients with LV dysfunction) showed no significant reduction in new AF among patients treated with these agents (1088/20,930 [5.0%] vs 1343/22,878 [5.9%]; relative risk, 0.92; 95% confidence interval, 0.80-1.05).

CONCLUSION

Although the incidence of AF was low, treatment with ramipril in this population without known LV systolic dysfunction did not significantly reduce this dysrhythmia.

Effect of renin-angiotensin aldosteron system blockers on postoperative atrial fibrillation

BACKGROUND

No randomized studies have been conducted to evaluate the effects of renin-angiotensin aldosteron system blockers on postoperative atrial fibrillation (AF). The aim of this study was to evaluate the effect of angiotensin converting-enzyme inhibitors (ACEIs) and ACEI plus candesartan, an angiotensin receptor blocker on postoperative AF.

METHODS

A group of consecutive patients undergoing coronary artery bypass and/or valve surgery was studied (n=128). The patients were randomized to ACEI group (n=49) and ACEI plus candesartan group (n=49). Thirty patients not on ACEI or angiotensin receptor blocker constituted the control group.

RESULTS

The rate of postoperative AF was higher in the control group (33.3%) compared to the ACEI group (12.2%, p=0.02) or ACEI plus candesartan group (10.2%, p=0.01). With the Cox proportional model, univariable negative predictors of postoperative AF, were the use of ACEI (RR 0.34, 95% CI 0.12 to 0.93, p=0.03) and the use of ACEI plus candesartan (RR 0.28, 95% CI 0.09 to 0.83, p=0.02); the positive predictor of postoperative AF was age>or=65 (RR 3.10, 95% CI 1.30 to 7.37, p=0.01). With the multivariable Cox proportional model, the only predictor of postoperative AF was age>or=65 (RR 9.70, 95% CI 2.04 to 46.1, p=0.004).

CONCLUSION

ACEI alone and ACEI plus candesartan decrease the incidence of postoperative AF compared to the control group. Candesartan has no additional effect on the rates of postoperative AF when added to ACEI.

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

The effect of statins on the incidence of new-onset atrial fibrillation (AF) in patients presenting with suspicion of acute coronary syndrome (ACS) is unknown. Our study population consisted of patients admitted to a tertiary care Veterans Administration hospital with suspicion of ACS between November 2001 and January 2006. All patients had an electrocardiogram on admission that was compared with a previous electrocardiogram to confirm new-onset AF or atrial flutter. Of 1,526 patients, 164 (10.8%) had new-onset AF and 601 (39.4%) were on a statin on admission. Patients with AF were significantly more likely to be older, Caucasian, have renal insufficiency and anemia, and less likely to be diabetic, on a statin or angiotensin-converting enzyme inhibitor on admission, or have chest pain as a presenting complaint. In univariate analysis, patients on statins were significantly less likely to have new-onset AF (odds ratio 0.40, 95% confidence interval 0.33 to 0.69, p <0.01). This relation persisted in the multivariate model (odds ratio 0.57, 95% confidence interval 0.39 to 0.83, p <0.01) after correcting for age, race, diabetes mellitus, chest pain, and use of angiotensin-converting enzyme inhibitor. In conclusion, patients presenting with suspicion of ACS were much less likely to have newonset AF if they were on a statin at time of presentation.

Role of Rac1 GTPase activation in atrial fibrillation

OBJECTIVES

We aimed to study the role of Rac1 GTPase in atrial fibrillation (AF).

BACKGROUND

The signal transduction associated with AF is incompletely understood. We hypothesized that activation of Rac1 GTPase contributes to the pathogenesis of AF via activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and production of reactive oxygen species.

METHODS

Old mice with cardiac-specific overexpression of constitutively active V12Rac1 (RacET) were compared with wild-type (WT) and WT undergoing transaortic constriction (TAC). In addition, samples of human left atrial appendages were analyzed in patients with sinus rhythm (SR) compared with patients with permanent AF matched for atrial diameter.

RESULTS

At age 16 months, 75% of RacET but no WT or TAC mice showed AF. Treatment of RacET with statins for 10 months did not alter weight or fibrosis of atria or ventricles but decreased cardiac Rac1 and NADPH oxidase activity and reduced the incidence of AF by 50%. The left atria of patients with AF showed increased fibrosis, up-regulation of NADPH oxidase activity, a 4-fold increase of Rac1 total protein and membrane expression as well as up-regulation of Rac1 activity.

CONCLUSIONS

Chronic cardiac overexpression of Rac1 represents a novel mouse model for AF. Rac1 GTPase contributes to the pathogenesis of AF and identifies a target for the prevention and treatment of AF.

Oxidative stress markers are associated with persistent atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) has been associated with myocardial oxidative stress, and antioxidant agents have demonstrated antiarrhythmic benefit in humans. We compared serum markers of oxidation and associated inflammation in individuals with or without AF.

METHODS

Serum markers of oxidative stress and inflammation were compared in a cross-sectional, case-control design study of 40 male individuals, with or without persistent or permanent AF, who were matched for age, sex, diabetes, and smoking status, known confounding variables for the measurement of oxidative stress. We used derivatives of reactive oxidative metabolites (DROMs) and ratios of oxidized to reduced glutathione (E(h) GSH) and cysteine (E(h) CySH) to quantify oxidative stress. We also measured inflammatory markers, including high-sensitivity C-reactive protein, interleukins 1beta and 6, and tumor necrosis factor alpha.

RESULTS

Univariate, conditional logistical regression analysis showed that oxidative stress but not inflammatory markers were statistically associated with AF (P <0.05). The increase in the odds ratios for AF for E(h) GSH, E(h) CySH, and DROMs were 6.1 (95% CI, 1.3-28.3; P = 0.02), 13.6 (95% CI, 2.5-74.1; P = 0.01), and 15.9 (95% CI, 1.7-153.9; P = 0.02), respectively. There was a stronger correlation between E(h) GSH and E(h) CySH (r = 0.66) than between E(h) GSH and DROMs (r = 0.41). In multivariate analysis corrected for statins and other AF risk factors differing between the groups, the association of AF and oxidative stress remained significant.

CONCLUSIONS

These data suggest that oxidative stress markers may have predictive value in AF management.

The relationship between statin use and atrial fibrillation

OBJECTIVE

To investigate the relationship between statin therapy and the development of new-onset, recurrent, and postoperative atrial fibrillation (AF).

RESEARCH DESIGN AND METHODS

A systematic literature search was conducted through September 2006. Included studies were either randomized, controlled trials or observational studies with adjusted analyses using multivariate regression or covariate matching, compared patients receiving or not receiving a statin, and reported data on the incidence of AF. Weighted averages were reported as odds ratios with 95% confidence intervals (CIs) using a random-effects model.

MAIN OUTCOME MEASURES

The primary outcome measured was a combined endpoint of any AF type. Secondary outcomes included new-onset, recurrent, and postoperative AF.

RESULTS

Fourteen trials reporting the results of 15 unique analyses (n = 7402) were included. There was a 20% incidence rate for any AF with varying rates depending on AF type (new-onset [11%], recurrent [56%], recurrent after cardioversion [54%], postoperative [22%]). The use of a statin reduced the odds of developing any AF by 45% (odds ratio [OR] 0.55; 95% CI 0.43-0.70); Q statistic p = 0.001). Statins reduced the odds of developing new-onset AF by 32% (OR 0.68; 95% CI 0.51-0.90), recurrent AF by 57% (OR 0.43; 95% CI 0.24-0.79), recurrent AF after cardioversion by 42% (OR 0.58; 95% CI 0.32-1.05) and postoperative AF by 58% (OR 0.42; 95% CI 0.27-0.65).

LIMITATIONS

We considered studies that were observational in nature or only available in abstract form. Publication bias could not be ruled out.

CONCLUSIONS

Statin therapy was associated with a reduced odds of developing AF, thus providing evidence of the benefit of statins beyond the lipid-lowering activity.

Postthoracotomy atrial fibrillation

PURPOSE OF REVIEW

Rapid atrial arrhythmias affect the elderly who undergo cardiac or noncardiac operations annually and have been associated with prolonged hospital stays. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of postoperative atrial arrhythmias.

RECENT FINDINGS

New risk factors and a prediction rule for postthoracotomy atrial fibrillation are discussed. Settings in which amiodarone prophylaxis against atrial fibrillation after cardiac surgery is appropriate are contrasted with evidence for postthoracotomy atrial fibrillation. Once atrial fibrillation develops, rate versus rhythm control strategies are reviewed. The most recent recommendations of the American Heart Association Task Force on the management of patients with atrial fibrillation are highlighted.

SUMMARY

Recent approaches directed at prophylaxis and acute therapy of atrial arrhythmias are discussed as are recommendations to prevent thromboembolic events.

Non-antiarrhythmic agents for prevention of postoperative atrial fibrillation: role of statins

PURPOSE OF REVIEW

Atrial fibrillation is the most common arrhythmia following cardiac surgery, having both serious medical and socioeconomic consequences. Although there are established antiarrhythmic agents for preventing and treating postoperative atrial fibrillation, these therapies are neither 100% reliable, nor without risks and limitations. Thus, there remains a strong need for non-antiarrhythmic, adjunctive therapies for the prevention of postoperative atrial fibrillation.

RECENT FINDINGS

Long-term statin administration in ambulatory patients is associated with a reduced risk of adverse cardiovascular events, including death, myocardial infarction, stroke, renal dysfunction and atrial fibrillation. Recent evidence suggests, however, that statins may also reduce the risk of acute adverse outcomes following invasive procedures, including postoperative atrial fibrillation. Although the exact mechanisms by which statins may reduce postoperative atrial fibrillation are unclear, accumulating evidence suggests that statins exert multiple effects independent of their effect on LDL cholesterol. For example, in patients with acute coronary syndromes, statin therapy has been shown to modulate remodeling of the cardiac extracellular matrix and to reduce markers of inflammation, including C-reactive protein, serum amyloid A, tumor necrosis factor-alpha, and IL-6.

SUMMARY

Perioperative statin therapy may represent an important non-antiarrhythmic, adjunctive therapeutic strategy for the prevention of postoperative atrial fibrillation.

Therapy with angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and statins: no effect on ablation outcome after ablation of atrial fibrillation

BACKGROUND

The renin-angiotensin-aldosterone system and inflammation are supposed to play a key role in the pathogenesis of atrial fibrillation (AF). This retrospective clinical study was intended to assess the influence of drugs with antiinflammatory and/or renin-angiotensin-aldosterone system-modulating properties, namely angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin II receptor blockers (ARBs), and statins, on AF-free survival after AF ablation.

METHODS

The study included 234 patients (23-80 years; 71.8% men) with drug-resistant paroxysmal (n = 165) or persistent AF (n = 69) who either underwent a Lasso-guided segmental pulmonary vein isolation (n = 83) or a CARTO-guided left atrial circumferential ablation (n = 151). Treatment with statins (n = 113), ACE-Is, or ARBs (n = 124), or a combination of a statin and an ACE-I or ARB (n = 75) was started >3 months before ablation and was continued during follow-up.

RESULTS

After a median follow-up of 12.7 months, 64% of patients with paroxysmal and 45% of patients with persistent AF were free of AF. Statin use (hazard ratio [HR], 1.06; P = .79), ACE-I or ARB use (HR, 1.12; P = .59), and their combined use (statin + ACE-I/ARB; HR, 1.17; P = .54) did not significantly influence ablation outcome as assessed by Cox regression analysis. In addition, after multivariate adjustment for potential confounders, the examined drugs did not significantly affect ablation outcome. Ablation induced an acute up-regulation of C-reactive protein levels (preablation vs 48 hours postablation, 5.9 +/- 8.1 vs 33.7 +/- 30 mg/L; P < .001) and other inflammatory markers. The examined drugs did not significantly alter baseline levels or ablation-induced up-regulation of inflammatory markers.

CONCLUSIONS

The routine use of statins, ACE-Is, or ARBs did not result in an improved outcome of AF ablation.

Statin therapy in cardiovascular diseases other than atherosclerosis

Statins are drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, thereby blocking the synthesis of cholesterol. Since being discovered in Japan in the mid 1970s, statins have been widely used to lower low-density lipoprotein cholesterol. However, analysis of cardiovascular research has revealed other important effects beyond changes in lipid parameters, referred to as pleiotropic effects. This paper focuses on the effects of statins as anti-ischemic agents with improvement in endothelial function, along with studies on valvular aortic stenosis, atrial fibrillation, heart failure, peripheral arterial disease, and cancer. As the evolution of statin research continues, there appear to be new potential benefits from statins to be found in many facets of cardiovascular disease.

Ratio of LDL- to HDL-Associated Platelet-Activating Factor Acetylhydrolase may be a Marker of Inflammation in Patients With Paroxysmal Atrial Fibrillation

BACKGROUND

A higher plasma concentration of highly-sensitive C-reactive protein (hs-CRP) has been found in patients with atrial fibrillation (AF). In addition, low-density lipoprotein (LDL)-associated platelet-activating factor acetylhydrolase (L-PAF-AH) is associated with inflammation. Therefore, the association between AF and PAF-AH was examined.

METHODS AND RESULTS

Eighty subjects who were not taking aspirin or statin were investigated, and classified into paroxysmal AF (n=41) and normal sinus rhythm (NSR, n=39) groups. The lipid profile was analyzed by capillary isotachophoresis (cITP), plasma hs-CRP, plasma PAF-AH, high-density lipoprotein (HDL)-associated (H-PAF-AH), and L-PAF-AH. Although there were no significant differences in total cholesterol, HDL, LDL, hs-CRP, or plasma PAF-AH between the 2 groups, L-PAF-AH and the L-PAF-AH/H-PAF-AH ratio in the paroxysmal AF group were both significantly higher than in the NSR group. Interestingly, the ratio of L-PAF-AH to H-PAF-AH positively correlated with the left atrial diameter in all subjects. Although there were no differences in plasma lipoprotein subfractions, as characterized by cITP, slow-migrating LDL positively correlated with L-PAF-AH in both groups.

CONCLUSIONS

The distribution of PAF-AH was associated with paroxysmal AF and may be a marker of inflammation in patients with paroxysmal AF. Antiinflammatory and antioxidant therapy that targets these factors might be effective for preventing paroxysmal AF.

Lipid-lowering therapy with statins, a new approach to antiarrhythmic therapy

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (statins) are the most effective and best-tolerated drugs to treat elevated levels of low-density lipoprotein cholesterol (LDL-C). In addition, they exhibit other effects unrelated to their lipid lowering effects (pleiotropic actions). In recent years, experimental and clinical evidence demonstrates that statins exert antiarrhythmic properties, reducing the recurrences of supraventricular and life-threatening ventricular arrhythmias both in patients with and without coronary artery disease (CAD). Thus, statins may constitute a novel therapeutic approach to cardiac arrhythmias. This article reviews the antiarrhythmic properties of statins as well as the possible mechanisms involved, including the lowering of LDL-C levels, the improvement of endothelial dysfunction and autonomic function, the stabilization of the atherosclerotic plaques, the antioxidant, antiinflammatory, antithrombotic and cardioprotective properties and the modulation of transmembrane ion fluxes.

Effect of perioperative corticosteroid use on the incidence of postcardiothoracic surgery atrial fibrillation and length of stay

BACKGROUND

While the mechanism underlying the development of post-cardiothoracic surgery atrial fibrillation has not been fully elucidated, it has been suggested that inflammation may play a causative role. Corticosteroids have been traditionally used to reduce inflammation, and when administered perioperatively, they may decrease the incidence of atrial fibrillation.

OBJECTIVE

The purpose of this study was to investigate the effects of corticosteroid administration on the incidence of post-cardiothoracic surgery atrial fibrillation and resultant hospital length of stay.

METHODS

A systematic literature search of MEDLINE, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews through July 2006 was conducted using specific search terms. A review of cardiology abstracts and a manual review of references were also performed. Studies that met the following criteria were included: randomized, controlled trials comparing patients receiving perioperative corticosteroids or placebo and reporting data on post-cardiothoracic surgery atrial fibrillation. A random-effects model was used.

RESULTS

Nine of the 1396 citations initially identified, representing 990 patients, met the inclusion criteria. Upon meta-analysis, corticosteroids significantly lowered patients' odds of developing post-cardiothoracic surgery atrial fibrillation by 45% (odds ratio [OR] 0.55; 95% confidence interval [CI] 0.39-0.78) and reduced hospital length of stay by approximately 1.6 days (weighted mean difference -1.59; 95% CI -2.96 to -0.21). Reductions in the incidence of post-cardiothoracic surgery atrial fibrillation appeared greatest in patients receiving intermediate doses of corticosteroid (50-210 mg dexamethasone equivalent), while both lower (up to 8 mg) and higher (236-2850 mg) dosing resulted in blunted effects.

CONCLUSION

Corticosteroids appear to reduce the incidence of post-cardiothoracic surgery atrial fibrillation and shorten hospital length of stay in randomized controlled trials.

Randomized Trial of Atorvastatin for Reduction of Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery

Background— Atrial fibrillation (AF) after cardiac surgery is associated with increased risk of complications, length of stay, and cost of care. Observational evidence suggests that patients who have undergone previous statin therapy have a lower incidence of postoperative AF. We tested this observation in a randomized, controlled trial.

Methods and Results— Two hundred patients undergoing elective cardiac surgery with cardiopulmonary bypass, without previous statin treatment or history of AF, were enrolled. Patients were randomized to atorvastatin (40 mg/d, n=101) or placebo (n=99) starting 7 days before operation. The primary end point was incidence of postoperative AF; secondary end points were length of stay, 30-day major adverse cardiac and cerebrovascular events, and postoperative C-reactive protein (CRP) variations. Atorvastatin significantly reduced the incidence of AF versus placebo (35% versus 57%, P =0.003). Accordingly, length of stay was longer in the placebo versus atorvastatin arm (6.9±1.4 versus 6.3±1.2 days, P =0.001). Peak CRP levels were lower in patients without AF ( P =0.01), irrespective of randomization assignment. Multivariable analysis showed that atorvastatin treatment conferred a 61% reduction in risk of AF (odds ratio 0.39, 95% confidence interval 0.18 to 0.85, P =0.017), whereas high postoperative CRP levels were associated with increased risk (odds ratio 2.0, 95% confidence interval 1.2 to 7.0, P =0.01). The incidence of major adverse cardiac and cerebrovascular events at 30 days was similar in the 2 arms.

Conclusions— Treatment with atorvastatin 40 mg/d, initiated 7 days before surgery, significantly reduces the incidence of postoperative AF after elective cardiac surgery with cardiopulmonary bypass and shortens hospital stay. These results may influence practice patterns with regard to adjuvant pharmacological therapy before cardiac surgery.