0
CHEST COVER IMAGE

IN THIS ISSUE

Articles

Executive Summary*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):1S-5S. doi:10.1378/chest.128.2_suppl.1S
FREE TO VIEW

This evidence-based clinical practice guideline provides a summary of the most current literature on the management of postoperative atrial fibrillation following cardiac surgery, and provides recommendations for the prevention and management of this condition based on the reported scientific data. The expert panel that developed these guidelines relied on results from randomized controlled trials (RCTs) that were identified through specified criteria related to predefined research questions. These questions focused on the following central areas:

Introduction*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):6S-8S. doi:10.1378/chest.128.2_suppl.6S
FREE TO VIEW

Atrial fibrillation (AF) and atrial flutter (AFL) are arrhythmias that commonly occur following cardiac surgery. The precipitating events are not always obvious, although predisposing factors including age have been defined. Postoperative AF and AFL add significantly to both the cost and morbidity of cardiac surgery. This guideline report, which was created under the auspices of the American College of Chest Physicians (ACCP), critically reviews evidence-based literature defining optimal treatment and prophylaxis for postoperative AF. Specific issues addressed include the following: (1) controlling the ventricular response rate in the patient with postoperative AF and AFL; (2) preventing thromboembolism in the setting of AF and AFL including the appropriate role of anticoagulation therapy; (3) pharmacologic approaches to converting AF or AFL to normal sinus rhythm, and maintaining normal sinus rhythm postoperatively; and (4) pharmacologic and surgical prophylaxis against postoperative AF and AFL. The resulting clinical practice guidelines represent the best-supported treatments, based on a rational scientific approach formulated from randomized clinical trials and systematic reviews. The panel convened by the Health and Sciences Policy Committee of the ACCP reviewed the currently available evidence to provide a basis for making specific recommendations for patient care.

Epidemiology, Mechanisms, and Risks*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):9S-16S. doi:10.1378/chest.128.2_suppl.9S
FREE TO VIEW

Atrial fibrillation (AF) is one of the most frequent complications of cardiac surgery, affecting more than one third of patients. The mechanism of this arrhythmia is believed to be reentry. The electrophysiologic substrate may be preexisting or may develop due to heterogeneity of refractoriness after surgery. Multiple perioperative factors have been proposed to contribute to the latter, including operative trauma, inflammation, elevations in atrial pressure (including that due to left ventricular diastolic dysfunction), autonomic nervous system imbalance, metabolic and electrolyte imbalances, or myocardial ischemic damage incurred during the operation. Whether ectopic beats originating in the pulmonary veins explain at least some episodes of postoperative AF, as has been shown for nonsurgical patients with the arrhythmia, is of current interest as such sites could easily be isolated at the time of surgery. The development of postoperative AF is associated with a higher risk of operative morbidity, prolonged hospitalization, and increased hospital cost compared with that in patients remaining in sinus rhythm. Many factors have been identified as being associated with postoperative AF, but the most consistent variable across studies is increasing patient age. It is speculated that age-related pathologic changes in the atrium contribute to arrhythmia susceptibility. An important modifiable risk factor for postoperative AF is the failure to resume therapy with β-adrenergic receptor blockers after surgery. The stratification of patients who are at higher risk for AF would focus preventative strategies on patients who are most likely to benefit from such therapy. Nonetheless, since postoperative AF often develops in patients with comorbidities who are predisposed to other complications and prolonged hospitalization, it is presently unclear whether the prevention of postoperative AF will result in improved patient outcomes, particularly shorter hospitalizations.

Methodological Approach*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):17S-23S. doi:10.1378/chest.128.2_suppl.17S
FREE TO VIEW

Atrial fibrillation remains a common and challenging problem following cardiac surgery. The American College of Chest Physicians, through the Health and Science Policy Committee, established a panel to develop a set of clinical practice guidelines for the management or prophylaxis of atrial fibrillation or flutter in patients undergoing coronary artery bypass surgery. The panel based its guidelines on a systematic review of the literature that included a computerized search of PubMed and CENTRAL, the Cochrane Collaboration database, as well as a search of selected journals and references in key articles. Studies were eligible for review if they were controlled trials. Paired reviewers assessed the quality of each eligible study and extracted relevant data. The resulting data were assembled into evidence tables organized by key management questions. The panel derived recommendations that were based on this review of evidence and were formulated according to the ACCP protocol for grading evidence and strength of recommendations.

Anticoagulation*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):24S-27S. doi:10.1378/chest.128.2_suppl.24S
FREE TO VIEW

Post-cardiac surgery atrial fibrillation (AF) places patients at risk for thromboembolism and stroke, while the surgery and cardiopulmonary bypass alter the multiple factors of coagulation and may increase the tendency to bleed. It is in the context of this complex clinical picture that the physician must make decisions regarding the risks and benefits of anticoagulation therapy to lower the risk for thromboembolism and stroke associated with postoperative AF. Physicians must also weigh the usually transient and self-limited duration of new-onset postoperative AF against the potential for postoperative bleeding if anticoagulation therapy is started. No randomized, controlled clinical trials are available that specifically address the problem of anticoagulation therapy for the postoperative AF. In that context, recommendations are based on the established therapy for nonsurgical situations modified by the potential risk of bleeding in the postoperative patient.

Intraoperative Interventions*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):28S-35S. doi:10.1378/chest.128.2_suppl.28S
FREE TO VIEW

A comprehensive evidence review was conducted of the medical literature regarding the relationship between intraoperative interventions and the incidence of postoperative atrial arrhythmias, including, most commonly, atrial fibrillation (AF). Fifteen randomized, controlled studies and one large-scale concurrent cohort study were identified that reported on the following issues: systemic temperature during surgery (one report); “beating heart” surgery vs conventional bypass surgery (three reports); type of myocardial protection (five reports); the use of adjunctive posterior pericardiotomy (one report); the use of thoracic epidural anesthesia (TEA) [two reports]; the use of glucose-insulin-potassium (GIK) solutions (two reports); and the use of heparin-coated circuits for cardiopulmonary bypass (CPB) [two reports]. Based on a systematic review of the reported data and an analysis of the quality of the reported data, we recommend the following: (1) that mild hypothermia, rather than moderate hypothermia, may be effective in reducing the frequency of postoperative AF; (2) the use of posterior pericardiotomy may be a useful adjunct to reduce the frequency of postoperative AF; and (3) the use of heparin-coated CPB circuits is associated with less postoperative AF. Because of conflicting or inadequate data, we cannot conclude that the frequency of postoperative AF is affected by (1) the use of beating-heart techniques, (2) the type of myocardial protection strategy used, (3) the use of TEA, or (4) the use of GIK solutions perioperatively.

The Role of Cardiac Pacing*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):36S-38S. doi:10.1378/chest.128.2_suppl.36S
FREE TO VIEW

New-onset atrial fibrillation (AF) occurs frequently after cardiac surgery. The utility of prophylactic atrial pacing to prevent AF following cardiac surgery has been investigated in a number of trials, but clinical guidelines for its use are lacking. Trials of prophylactic atrial pacing to prevent AF following cardiac surgery were identified by searching PubMed, the Cochrane database, selected medical journals, and references in selected articles. Nine randomized controlled trials were identified that addressed prophylactic atrial pacing after cardiac surgery to prevent AF. Prophylactic right atrial pacing and prophylactic left atrial pacing have yielded inconclusive results. Prophylactic biatrial pacing (BAP) reduced the incidence of AF significantly in four studies, reduced it nonsignificantly in one study, and had no effect in one study. On the basis of the literature that was reviewed and graded for quality, it was concluded that prophylactic atrial pacing to prevent AF after cardiac surgery is safe. We recommend that BAP be considered, particularly in patients who are at high risk for the development of postoperative AF.

Pharmacologic Prophylaxis*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):39S-47S. doi:10.1378/chest.128.2_suppl.39S
FREE TO VIEW

New-onset atrial fibrillation (AF) occurs frequently in patients after cardiac surgery. The purpose of this study was to review the published trials and to provide clinical practice guidelines for pharmacologic prophylaxis against postoperative AF. Trials of pharmacologic prophylaxis against AF after heart surgery were identified by searching MEDLINE, the Cochrane Controlled Trials Register, and the bibliographies of published reports. Evidence grades and clinical recommendation scores were assigned to each prophylactic drug based on published evidence. Ninety-one trials were identified. The primary study design was a randomized, controlled trial of one drug vs placebo/usual care. Pharmacologic therapies that are reviewed include Vaughan-Williams class II agents (ie, β-receptor antagonists) [29 trials; 2,901 patients], Vaughan-Williams class III agents (ie, sotalol and amiodarone) [18 trials; 2,978 patients], Vaughan-Williams class IV agents (ie, verapamil and diltiazem) [5 trials; 601 patients], and Vaughan-Williams class I agents (ie, quinidine and procainamide) [3 trials; 246 patients], as well as digitalis (10 trials; 1,401 patients), magnesium (14 trials; 1,853 patients), dexamethasone (1 trial; 216 patients), glucose-insulin-potassium (3 trials; 102 patients), insulin (1 trial; 501 patients), triiodothyronine (2 trials; 301 patients), and aniline (1 trial; 32 patients). A consistent finding in this review is that antiarrhythmic drugs with β-adrenergic receptor-blocking effects (ie, class II beta-blockers, sotalol, and amiodarone) demonstrated successful prophylaxis. Furthermore, those therapies that did not inhibit β-receptors generally failed to demonstrate a decreased incidence in postoperative AF. While sotalol and amiodarone have been shown in some studies to be effective, their safety and the incremental prophylactic advantage in comparison with beta-blockers has not been conclusively demonstrated. On the basis of evidence that has been reviewed and graded for quality, it is recommended that strong consideration should be given to the prophylactic administration of Vaughan-Williams class II beta-blocking drugs as a means of lowering the incidence of new-onset post-cardiac surgery AF.

Pharmacologic Control of Rhythm*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):48S-55S. doi:10.1378/chest.128.2_suppl.48S
FREE TO VIEW

Of the 128 articles evaluated on the overall topic of atrial fibrillation (AF) after cardiac surgery, only 19 studies dealing with pharmacologic heart rhythm control were relevant for inclusion in this analysis, indicating the relative paucity of evidence-based studies addressing this topic. We found limited data on guiding treatment for the rhythm control of AF following cardiac surgery in patients who do not require urgent cardioversion; therefore, the choice of an antiarrhythmic drug needs to be guided by patient characteristics. Based on limited available evidence, amiodarone is recommended for pharmacologic conversion of postoperative AF and AFL in patients with depressed left ventricular function who do not need urgent electrical cardioversion. This recommendation is made largely because of the effectiveness of amiodarone and also because of its relatively favorable side-effects profile. Sotalol and class 1A antiarrhythmic drugs are reasonable choices for patients with coronary artery disease who do not have congestive heart failure. There are currently no definitive data to guide the decision about the duration of antiarrhythmic drug therapy for patients with AF following cardiac surgery. Most protocols continue therapy with the antiarrhythmic drug for 4 to 6 weeks following surgery, but evidence from randomized studies is lacking.

Pharmacologic Control of Ventricular Rate*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):56S-60S. doi:10.1378/chest.128.2_suppl.56S
FREE TO VIEW

While there is a deficiency in the number of randomized control studies dealing with the pharmacologic control of the ventricular response to atrial fibrillation (AF) or atrial flutter (AFL) after cardiac surgery, evidence-based recommendations are presented from those studies that are available. Because of the hyperadrenergic state after surgery, beta-blockers are recommended as the first line of therapy for patients with AF or AFL who do not require urgent cardioversion. Calcium channel blockers are recommended as second-line therapeutic agents. Digoxin has little efficacy because of the heightened adrenergic tone that is present postoperatively. Agents that are proarrhythmic, such as dofetilide, or agents that are contraindicated in patients with coronary artery disease, such as flecainide and propafenone, are not recommended.

Future Directions*: American College of Chest Physicians Guidelines for the Prevention and Management of Postoperative Atrial Fibrillation After Cardiac Surgery
Chest. 2005;128(2_suppl):61S-64S. doi:10.1378/chest.128.2_suppl.61S
FREE TO VIEW

The recommendations put forth in these guidelines for the management and prevention of atrial fibrillation (AF) after cardiac surgery are based on information available at the time of the final literature review. As a result, they will become dated as new information and results from new trials becomes available. The maintenance of clinical practice guidelines is an evolving process requiring the alteration of recommendations over time, based on new studies and new results. The current set of guidelines attempts not only to identify new therapeutic options for AF after cardiac surgery but also to develop a strategy to indicate how and when to update the guidelines themselves.

Sign In to Access Full Content

Don't have an account?

Register for a FREE personal account to access these and other personalization features:

Register
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543