Efficacy and safety of low- and high-dose sotalol versus propranolol in the prevention of supraventricular tachyarrhythmias early after coronary artery bypass operations

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.

Is the Preoperative Administration of Amiodarone or Metoprolol More Effective in Reducing Atrial Fibrillation: After Coronary Bypass Surgery?

This study examined the influence of preoperative administration of amiodarone and metoprolol in preventing postoperative atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery.The study comprised 251 patients who underwent CABG surgery at our hospital between January 2012 and May 2014. The patients were randomly divided into 2 groups: amiodarone therapy group (n = 122 patients) and metoprolol therapy group (n = 129 patients).In the amiodarone group, the patients received amiodarone tablet orally 1 week before coronary bypass surgery and during the postoperative period. In the metoprolol group, the patients received metoprolol tablet orally 1 week before surgery and during the postoperative period. The AF development rate was retrospectively evaluated between the first 3 days and 4 weeks after surgery.AF developed in 14 patients in the amiodarone group and 16 patients in the metoprolol group 4 weeks after the operation (P = 0.612).No significant difference was observed between the groups in terms of intensive care unit and hospital stay. Furthermore, hospital charges were similar in both groups (P = 0.741).The results of the logistic regression analysis showed age, left ventricular ejection fraction, left atrial diameter, and aortic cross-clamping time to be predictors for postoperative AF.This study demonstrates that amiodarone and metoprolol have similar effects in prevention of AF after cardiac surgery. However, larger-scale studies need to be conducted to substantiate these findings.

Pharmacological strategies for prevention of postoperative atrial fibrillation

Atrial fibrillation (AF) complicating cardiac surgery continues to be a major problem that increases the postoperative risk of stroke, myocardial infarction, heart failure and costs and can affect long-term survival. The incidence of AF after surgery has not significantly changed over the last two decades, despite improvement in medical and surgical techniques. The mechanism and pathophysiology underlying postoperative AF (PoAF) is incompletely understood and results from a combination of acute and chronic factors, superimposed on an underlying abnormal atrial substrate with increased interstitial fibrosis. Several anti-arrhythmic and non-anti-arrhythmic medications have been used for the prevention of PoAF, but the effectiveness of these strategies has been limited due to a poor understanding of the basis for the increased susceptibility of the atria to AF in the postoperative setting. In this review, we summarize the pathophysiology underlying the development of PoAF and evidence behind pharmacological approaches used for its prevention in the postoperative setting.

Ivabradine Versus Beta-Blockers in Patients with Conduction Abnormalities or Left Ventricular Dysfunction Undergoing Cardiac Surgery

INTRODUCTION

In patients with conduction abnormalities or left ventricle (LV) dysfunction the use of β-blockers for post cardiac surgery rhythm control is difficult and controversial, with a paucity of information about other drugs such ivabradine used postoperatively. The objective of this study was to compare the efficacy and safety of ivabradine versus metoprolol used perioperatively in cardiac surgery patients with conduction abnormalities or LV systolic dysfunction.

METHODS

This was an open-label, randomized clinical trial enrolling 527 patients with conduction abnormalities or LV systolic dysfunction undergoing coronary artery bypass grafting or valvular replacement, randomized to take ivabradine or metoprolol, or metoprolol plus ivabradine. The primary endpoints were the composites of 30-day mortality, in-hospital atrial fibrillation (AF), in-hospital three-degree atrioventricular block and need for pacing, in-hospital worsening heart failure (HF; safety endpoints), duration of hospital stay and immobilization and the above endpoint plus in-hospital bradycardia, gastrointestinal symptoms, sleep disturbances, cold extremities (efficacy plus safety endpoint).

RESULTS

Heart rate reduction and prevention of postoperative AF or tachyarrhythmia with combined therapy was more effective than with metoprolol or ivabradine alone during the immediate postoperative management of cardiac surgery patients. In the Ivabradine group, the frequency of early postoperative pacing and HF worsening was smaller than in the Metoprolol group and in combined therapy group. The frequency of primary combined endpoint was lower in the combined Ivabradine + Metoprolol group compared with the monotherapy groups.

CONCLUSION

Considering efficacy and safety, the cardiac rhythm reduction after open heart surgery in patients with conduction abnormalities or LV dysfunction with ivabradine plus metoprolol emerged as the best treatment in this trial.

The efficacy of sotalol in preventing postoperative atrial fibrillation: a meta-analysis

OBJECTIVE

Supraventricular tachyarrhythmias including atrial fibrillation are common and troubling complications after cardiac surgery, and thus considerable interest in pharmacologic prophylaxis has developed. The aim of this study was to evaluate the efficacy of sotalol in the prevention of postoperative supraventricular tachyarrhythmias.

METHODS

Standard methods of meta-analysis were used. Randomized clinical trials published in English language were eligible for the meta-analysis.

RESULTS

A systematic review revealed 15 eligible publications that provided 20 comparisons of sotalol with a control group. The incidence and relative risk (RR) with 95% confidence interval (CI) of developing postoperative supraventricular tachyarrhythmias while taking sotalol were sotalol (n=489) versus placebo (n=499): 22.5% versus 41.5%, RR=0.55 (CI, 0.454-0.667, P<.001); sotalol (n=304) versus no treatment (n=311): 12% versus 39%, RR=0.329 (CI, 0.236-0.459, P<.001); sotalol (n=488) versus beta-blocker (n=555): 14% versus 23%, RR=0.644 (CI, 0.495-0.838, P<.001); sotalol (n=139) versus amiodarone (n=146): no significant differences in supraventricular tachyarrhythmia prevention; and sotalol (n=51) versus magnesium (n=54): no significant differences in supraventricular tachyarrhythmia prevention. Initiating sotalol orally or intravenously had no significant effect on efficacy. Initiating sotalol after surgery showed a trend toward less adverse events (before: RR=1.700 [CI, 0.903-3.200] and after: RR=0.767 [CI, 0.391-1.505]).

CONCLUSION

Sotalol is more effective in the prevention of supraventricular tachyarrhythmia than placebo or beta-blockers. Initiating sotalol before cardiac surgery has no advantage compared with initiating sotalol shortly after surgery. Starting sotalol intravenously after surgery may be a more reliable method than administering via a nasogastric tube or delaying treatment until the patient can take oral medication.

Pharmacologic prophylaxis for atrial fibrillation following cardiac surgery: a systematic review

Atrial Fibrillation (AF) is the most common arrhythmia occurring after cardiac surgery. Its incidence varies depending on type of surgery. Postoperative AF may cause hemodynamic deterioration, predispose to stroke and increase mortality. Effective treatment for prophylaxis of postoperative AF is vital as reduces hospitalization and overall morbidity. Beta-blockers, have been proved to prevent effectively atrial fibrillation following cardiac surgery and should be routinely used if there are no contraindications. Sotalol may be more effective than standard b-blockers for the prevention of AF without causing an excess of side effects. Amiodarone is useful when beta-blocker therapy is not possible or as additional prophylaxis in high risk patients. Other agents such as magnesium, calcium channels blocker or non-antiarrhythmic drugs as glycose-insulin--potassium, non-steroidal anti-inflammatory drugs, corticosteroids, N-acetylcysteine and statins have been studied as alternative treatment for postoperative AF prophylaxis.

Effect of low-dose landiolol, an ultrashort-acting beta-blocker, on postoperative atrial fibrillation after CABG surgery

OBJECTIVE

Postoperative atrial fibrillation is the most common complication after coronary artery bypass grafting (CABG). This complication is associated with prolongation of the intensive care unit stay and hospitalization time with attendant increased hospitalization costs, and it is an important risk factor for perioperative cerebrovascular accidents. Landiolol is a newly developed ultrashort-acting beta-adrenoceptor antagonist with a half-life of 3 min that is eight times more cardioselective than esmolol. The purpose of this study was to investigate the prophylactic effect of continuous administration of low-dose landiolol on postoperative atrial fibrillation.

METHODS

We reviewed all patients who underwent CABG alone at our hospital from April 2002 and September 2006. Patients with a previous history of atrial arrhythmias were excluded. The remaining patients were divided to two groups: landiolol group (n = 20), and control group (n = 35). Administration of landiolol started after cardiopulmonary bypass with a loading dose of 1.5-2.5 mug.kg(t-1).min(-1) and continued for the first 2 days after surgery. The incidence of postoperative atrial fibrillation was noted. Continuous variables were compared between groups by means of Student's t-test. Categorical variables were compared by means of the chi(2) test or Fisher's exact test.

RESULTS

The occurrence of atrial fibrillation after CABG in the control group was statistically more than in the landiolol group (P = 0.04). There were no statistical differences between the groups regarding the cardiac index or the dose of inotropic agents during the perioperative period.

CONCLUSION

Intraoperative and perioperative administration of low-dose landiolol has a preventive effect on the appearance of atrial fibrillation after CABG surgery.

Prevention of atrial fibrillation after cardiac surgery

Atrial fibrillation is the most common arrhythmia occurring after heart surgery. Its prevalence after coronary artery bypass surgery is 17-33%. Atrial fibrillation requires additional treatment, lengthens hospitalization and increases the overall expenses of cardiac surgery. Atrial fibrillation can cause hemodynamic problems, predispose to congestive heart failure and increase the risk of stroke. Beta-blockers have been shown to effectively prevent atrial fibrillation, and beta-blockers should be a part of the medication of every patient undergoing cardiac surgery, if there are no contraindications. Amiodarone therapy can also be considered for especially high-risk patients.

The Clinical Noncompliance of Oral Sotalol/Magnesium for Prophylactic Treatment of Atrial Fibrillation After Coronary Artery Bypass Grafting

BACKGROUND

Postoperative atrial fibrillation has been refractory to many attempted pharmacologic prevention methods and, when effective, side effects have been described. The present aim was to study the clinical compliance of a suggested prophylactic treatment, oral sotalol, and magnesium.

METHODS

Coronary-bypass patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium supplementation were enrolled (n = 49) with an intention-to-treat strategy and being compared with a matched control group (n = 844). A protocol listed exclusion criteria of clinical compliance that was postoperatively evaluated prior to and during treatment.

RESULTS

Twenty-seven of the 49 enrolled patients (55%) were compliant to sustain the treatment according to the protocol. The remaining patients were postoperatively excluded, mainly because of hemodynamic reasons, of whom 14 were noncompliant to initiate any treatment. The AF occurrence in the compliant group was 7% versus 36% in noncompliant patients (p = 0.035), and 24% in the control group (p = 0.076). However, with an intention-to-treat policy the overall AF incidence became 18%. The subgroups of enrolled patients demonstrated skewing phenomena. The noncompliant group had higher requirement for inotropic support (p = 0.029) and longer aortic cross-clamp time (p = 0.048) compared to compliant patients. Further, the body weight of noncompliant patients was markedly lower than in the compliant counterpart (p = 0.015).

CONCLUSIONS

The tested treatment protocol showed limited compliance among routine cardiac-surgery patients, and further, introduced a biased selection of patients that skewed the results and may have partly explained the treatment effect.

Amiodarone Prophylaxis for Atrial Fibrillation After Cardiac Surgery: Meta-Analysis of Dose Response and Timing of Initiation

STUDY OBJECTIVE

To investigate a possible dose-response relationship between amiodarone and reduction in incidence of postoperative atrial fibrillation, and to determine whether pre- or postoperative initiation of amiodarone is superior.

DESIGN

Meta-analysis of randomized controlled trials.

DATA SOURCE

MEDLINE and EMBASE databases and the Cochrane Central Register of Controlled Trials for English-language reports published between 1966 and December 2005.

MEASUREMENTS AND MAIN RESULTS

Of 23 identified randomized controlled trials of amiodarone prophylaxis of postoperative atrial fibrillation, 14 were included in the final analysis. These studies enrolled a total of 2864 patients. For each study, the total administered amiodarone dose--categorized as low (< 3000 mg), medium (3000-5000 mg), or high (> 5000 mg)--and preoperative versus postoperative initiation were aggregated by using meta-analytic techniques. The incidence of postoperative atrial fibrillation was significantly reduced by amiodarone compared with placebo (p<0.001). Although the odds of developing atrial fibrillation appeared to be somewhat higher in the low-dose group, no significant differences were noted in the odds ratios (ORs) of developing atrial fibrillation among the low-, medium-, and high-dose groups: OR 0.58, 95% confidence interval (CI) 0.44-0.77; OR 0.45, 95% CI 0.30-0.69; and OR 0.44, 95% CI 0.33-0.58; respectively (p=0.238). In addition, the ORs for atrial fibrillation development associated with preoperative and postoperative initiation of amiodarone were not significantly different (OR 0.50, 95% CI 0.39-0.63; and OR 0.48, 95% CI 0.37-0.63; respectively, p=0.862).

CONCLUSION

Total amiodarone doses of 3000 mg or higher may be more effective than lower doses in reducing the rate of postoperative atrial fibrillation after cardiac surgery. Preoperative initiation of amiodarone appears to be unnecessary. These findings require confirmation in prospective, randomized trials.

Pharmacologic Prophylaxis

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, beta-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 beta-adrenergic receptor-blocking effects (ie, class II beta-blockers, sotalol, and amiodarone) demonstrated successful prophylaxis. Furthermore, those therapies that did not inhibit beta-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.

Atrial fibrillation after cardiac surgery: an evidence-based approach to prevention

A number of advances in surgical and anesthetic techniques have reduced the risk for patients undergoing cardiac surgery. However, postoperative atrial fibrillation remains common, with an incidence ranging between 25% and 40%. It is associated with an increased incidence of congestive heart failure, renal insufficiency, and stroke that prolongs hospitalization and increases rates of readmission after discharge. Consequently, there has been great interest in strategies to prevent this arrhythmia. When both safety and efficacy are considered, the available evidence to date suggests that only beta-blockers can be recommended for the prevention of atrial fibrillation after cardiac surgery. Other treatments might be considered on an individual basis after careful consideration of the patient's potential for side effects.

Pharmacologic Strategies for Prevention of Atrial Fibrillation After Open Heart Surgery

Postoperative atrial fibrillation is a common complication after open heart surgery; it increases morbidity, hospital stay, and costs. In an analysis of 8 large cardiac surgery trials totaling 20,193 patients, the incidence of postoperative atrial fibrillation was estimated to be 26% and ranged from 17% to 35%. We reviewed the results of 52 studies published between 1966 and 2003 that evaluated pharmacologic strategies to prevent postoperative atrial fibrillation in nearly 10,000 patients undergoing open heart operations. Supraventricular tachyarrhythmias, including atrial fibrillation, after open heart operations occurred in 29% of patients who did not receive prophylactic drugs, compared with 12% in patients who received intravenous followed by oral amiodarone, 15% in those given sotalol, 16% in those given oral amiodarone, and 19% in those given beta-blockers. Pharmacologic strategies and regimens aimed at preventing postoperative atrial fibrillation are necessary to optimize the postoperative care of patients undergoing open heart operations. Although no strategy has consistently been shown to be superior to another, the most effective approach to preventing postoperative atrial fibrillation likely involves multiple interventions. In the absence of contraindications, all patients should receive beta-blocker therapy before and after the operation. For patients with 1 or more risk factors for postoperative atrial fibrillation, regimens consisting of either sotalol (beta-blocker with class III antiarrhythmic properties) alone or beta-blockers in combination with amiodarone seem to be the safest, most effective pharmacologic strategies for preventing postoperative atrial fibrillation.

Pharmacological management of atrial fibrillation following cardiac surgery

Atrial fibrillation (AF) is the most common complication following coronary artery bypass graft surgery (CABG). Post-CABG AF occurs most commonly on the second postoperative day and declines in incidence thereafter. A number of risk factors have been found to be associated with a higher frequency of post-CABG AF. These risk factors include advanced age, a prior history of AF, hypertension, and heart failure. Postoperative complications--including low cardiac output, use of an intra-aortic balloon pump, pneumonia, and prolonged mechanical ventilation--are also associated with higher rates of post-CABG AF. Post-CABG AF increases the risk of stroke, and the length and cost of hospitalization. Prophylactic administration of conventional beta-adrenoceptor antagonists (beta-blockers) or sotalol produces a consistent and significant reduction in the incidence of post-CABG AF; however, results with prophylactic amiodarone or magnesium are less consistent. Termination of post-CABG AF, once it occurs, can be accomplished with a number of antiarrhythmic agents. Ibutilide has been the most widely studied agent for this indication. Sotalol is not indicated for cardioversion of AF and has not been studied in the post-CABG setting. Electrical cardioversion and biatrial pacing have also been used to terminate post-CABG AF. Ventricular rate is best controlled with beta-blockers and calcium channel antagonists. Esmolol has a rapid onset of action and is easily titrated to effect. Digoxin can control the ventricular rate, but has a slow onset of action. There are limited data available to guide decisions regarding the optimal management of post-CABG AF.

Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery

BACKGROUND

Post-operative atrial fibrillation is a common complication of cardiac surgery and has been associated with increased incidence of other complications including post-operative stroke, increased hospital length of stay and increased cost of hospitalisation. Prevention of atrial fibrillation is a reasonable clinical goal and, consequently, many randomised trials have evaluated the effectiveness of pharmacological and non-pharmacological interventions. We systematically reviewed the literature and prepared meta-analyses to better understand the role and effects of various prophylactic therapies against post-operative atrial fibrillation.

OBJECTIVES

To assess the effects of pharmacological and non-pharmacological interventions for preventing post-cardiac surgery atrial fibrillation.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE and CINAHL from earliest achievable date to June 2003. We hand searched references from reports and earlier reviews. We searched abstract books and CD-ROMs from annual scientific meetings of American College of Cardiology, American Heart Association, North American Society of Pacing and Electrophysiology and European Heart Organization between 1997-2003. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials comparing pharmacological interventions or non-pharmacological interventions with control treatment, placebo or usual care for the prevention of post-operative atrial fibrillation in post-coronary artery bypass grafting or combined CABG and valvular surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Fifty eight studies were included with a total of 8565 participants. Interventions included were amiodarone, beta blockers, solatol and pacing. Results favoured treatment for post-operative atrial fibrillation. The data for stroke favoured treatment by a non-significant effect size of 0.81, 95% confidence interval 0.51 to 1.28. Similarly, a positive indication for length of stay was derived but it too was not significant with a weighted mean difference of -0.66, 95% confidence interval -0.95 to -0.37. A positive result for cost of hospitalisation in favour of treatment was achieved, but the statistic is not significant due to low power and large standard deviations: a weighted mean difference of -2717, 95% confidence interval 7518 to 2084. Beta-blockers had the greatest magnitude of effect across 28 trials (4074 patients) with an odds ratio (random) of 0.35, 95% confidence interval 0.26 to 0.49. Across all treatment, the odds ratio favoured treatment with a ratio (random) of 0.43, 95% confidence interval 0.37 to 0.51.

REVIEWERS' CONCLUSIONS

Intervention is favoured across the three pharmacological interventions studied and the one non-pharmacological intervention, pacing. The length of stay data favoured treatment (-0.66, 95% confidence interval -0.95 to -0.37).

Amiodarone versus sotalol for the treatment of atrial fibrillation after open heart surgery: the Reduction in Postoperative Cardiovascular Arrhythmic Events (REDUCE) trial

OBJECTIVES

This prospective, randomized, double-blind, placebo-controlled study compared the efficacy and safety of amiodarone and sotalol in the prevention of atrial fibrillation (AF) following open heart surgery.

BACKGROUND

The incidence of supraventricular arrhythmias following open heart surgery ranges from 20% to 40%, with AF being the most common. Both amiodarone and sotalol have been shown to be effective in reducing postoperative arrhythmias, but no direct comparison of these agents has been conducted.

METHODS

A total of 160 patients were randomized, of whom 134 underwent coronary artery bypass graft surgery (CABG) alone, 17 underwent CABG and concomitant aortic valve replacement surgery (AVR), 9 underwent AVR only, and 1 patient's surgery was canceled. Patients with signs or symptoms of congestive heart failure (CHF), ejection fraction < or =30%, estimated creatinine clearance <30 mL/min, or serum creatinine > or =2.5 mg/dL were excluded. Patients were randomized to receive either sotalol 80 mg 2 times per day (n = 76) or intravenous amiodarone 15 mg/kg over 24 hours followed by oral amiodarone 200 mg 3 times per day (n = 83). Study drug was started at the time of surgery and continued for 7 days or until discharge, whichever came first.

RESULTS

AF occurred in 17% of patients randomized to amiodarone and 25% of the patients randomized to sotalol (P =.21). However, the duration of AF was significantly shorter in amiodarone-treated patients (169 +/- 224 min) compared to sotalol treated patients (487 +/- 505 min; P =.04). In a subgroup analysis, the incidence of AF in patients undergoing AVR or CABG with AVR was significantly less with amiodarone (1/15, 7%) compared to sotalol (9/11, 82%) (P <.001). Blood pressure was lower immediately after surgery with amiodarone but comparable to sotalol at 24 hours. Of the hemodynamic indices measured, only stroke volume was significantly lower in patients randomized to sotalol at 24 hours (P =.035).

CONCLUSIONS

Amiodarone and sotalol share similar efficacy and safety in reducing postoperative AF. Hemodynamic effects were similar between both drugs at 24 hours, with the exception that stroke volume was lower in sotalol-treated patients. In patients undergoing more complex surgery, postoperative AF occurred more frequently with sotalol than with amiodarone.

Efficacy of nonsteroidal anti-inflammatory medications for prevention of atrial fibrillation following coronary artery bypass graft surgery

This study was designed to test whether nonsteroidal anti-inflammatory medications could reduce the frequency of atrial fibrillation after coronary artery bypass graft surgery. The study was designed as an open-label, randomized trial. Patients undergoing first-time coronary artery bypass graft surgery were considered eligible. Patients with a history of atrial fibrillation, serum creatinine >2.0 mg/dL, on antiarrhythmic treatment, and those undergoing concomitant valvular surgery were excluded. The study was conducted in a single, university-affiliated community hospital. The researchers' role in the study was restricted to randomizing the patients and collecting data. The primary clinical care team made all decisions regarding patient care. One hundred patients were randomized to two groups: one received 30 mg ketorolac intravenously every 6 hours until able to take oral medications, at which point the patients were switched to 600 mg ibuprofen orally three times a day; the other group received conventional treatment. The primary end point of the study was incidence of atrial fibrillation in the immediate postoperative period. Atrial fibrillation occurred in 14 patients (28.6%) in the conventional treatment group vs. five patients (9.8%) in the ibuprofen group (p<0.017). Nonsteroidal anti-inflammatory medications were relatively safe and effective in significantly reducing the incidence of atrial fibrillation after coronary artery bypass graft surgery.

A comparison between oral antiarrhythmic drugs in the prevention of atrial fibrillation after cardiac surgery: the pilot study of prevention of postoperative atrial fibrillation (SPPAF), a randomized, placebo-controlled trial

BACKGROUND

Atrial fibrillation (AF) frequently occurs after cardiac surgical procedures, and beta-blockers, sotalol, and amiodarone may reduce the frequency of AF after open heart surgery. This pilot trial was designed to test whether each of the active oral drug regimens is superior to placebo for prevention of postoperative AF and whether there are differences in favor of 1 of the preventive strategies.

METHODS AND RESULTS

We conducted a randomized, double-blinded, placebo-controlled trial in which patients undergoing cardiac surgery in the absence of heart failure and without significant left ventricular dysfunction (n = 253; average age, 65 +/- 11 years) received oral amiodarone plus metoprolol (n = 63), metoprolol alone (n = 62), sotalol (n = 63), or placebo (n = 65). Patients receiving combination therapy (amiodarone plus metoprolol) and those receiving sotalol had a significantly lower frequency of AF (30.2% and 31.7%; absolute difference, 23.6% and 22.1%; odds ratios [OR], 0.37 [95% CI, 0.18 to 0.77, P <.01 vs placebo] and 0.40 [0.19 to 0.82, P =.01 vs placebo]) compared with patients receiving placebo (53.8%). Treatment with metoprolol was associated with a 13.5% absolute reduction of AF (P =.16; OR, 0.58 [0.29 to 1.17]. Treatment effects did not differ significantly between active drug groups. Adverse events including cerebrovascular accident, postoperative ventricular tachycardia, nausea, and dyspepsia, in hospital death, postoperative infections, and hypotension, were similar among the groups. Bradycardia necessitating dose reduction or drug withdrawal occurred in 3.1% (placebo), 3.2% (combined amiodarone and metoprolol; P =.65 vs placebo), 12.7% (sotalol; P <.05 vs placebo), and 16.1% (metoprolol; P <.05 vs placebo). Patients in the placebo group had a nonsignificantly longer length of hospital stay as compared with the active treatment groups (13.1 +/- 8.9 days vs 11.3 +/- 7; P =.10), with no significant difference between the active treatment groups.

CONCLUSIONS

Oral active prophylaxis with either sotalol or amiodarone plus metoprolol may reduce the rate of AF after cardiac surgery in a population at high risk for postoperative AF. Treatment with metoprolol alone resulted in a trend to a lower risk for postoperative AF.

Management of atrial fibrillation in the post-cardiac surgery setting

New onset postcardiac surgery AF is a prevalent problem associated with increased morbidity, hospital expense, and length of stay. Those agents that inhibit beta-adrenergic receptors (class II beta-blockers, sotalol, and amiodarone) have been demonstrated to be successful prophylaxis against postoperative AF. Furthermore, those therapies that do not inhibit beta-receptors are not effective prophylactic agents. Until comparative trials demonstrate a significant reduction in postoperative AF without additional adverse effects for sotalol or amiodarone compared with beta-blockers, class II beta-blockers are the preferred prophylactic therapy. If patients are deemed unable to take beta-blockers, amiodarone is likely the best alternative. Although prophylaxis against postoperative AF seems prudent, the impact of prophylactic therapy on length of stay and hospital costs has not been a primary objective of any randomized trial. Furthermore, no studies have compared prophylactic therapy for every patient versus therapy only for those patients who experience AF after heart surgery. In the absence of data from randomized clinical trials, postoperative AF should be managed in a similar fashion to clinical AF with attention to rate control, anticoagulation, and restoration of sinus rhythm.

Atrial fibrillation and cardiac surgery

PURPOSE OF REVIEW

To discuss the pathophysiology, risk factors, and treatments for atrial fibrillation occurring after cardiac surgery.

RECENT FINDINGS

Atrial fibrillation occurs frequently after cardiac surgery and it may lead to patient morbidity. Many variables have been suggested to be associated with this arrhythmia, but only advanced patient age can consistently identify risk for this complication. Immediate electrical cardioversion is indicated when the arrhythmia leads to hemodynamic instability or myocardial ischemia. Otherwise treatment is aimed at heart rate control, elective cardioversion with drugs or electrical means, and anticoagulation when the arrhythmia persists. Multiple investigations have evaluated methods for preventing postoperative atrial fibrillation, but only beta-adrenergic receptor blocking drugs have been consistently shown to be effective, and then not in all patients. Surgical treatments are increasingly being considered as a therapeutic means for ameliorating chronic atrial fibrillation. The use of these procedures has been simplified with the development of devices that can generate linear scars in the atrium and around the pulmonary vein orifices. These simplifications will allow for broader application of these techniques to patients undergoing other cardiac surgery (e.g. mitral valvular surgery).

SUMMARY

Atrial fibrillation is one of the most common complications of cardiac surgery. There are three major aims for treating atrial fibrillation: conversion to sinus rhythm, heart rate control, and anticoagulation. Only beta-blockers can be recommended for prophylaxis against postoperative atrial fibrillation. Further refinements in surgical treatments for atrial fibrillation may allow for wider applications of this therapy with lower rates of complications.

Double-blind, placebo-controlled, randomized trial of prophylactic metoprolol for reduction of hospital length of stay after heart surgery: the beta-Blocker Length Of Stay (BLOS) study

BACKGROUND

Atrial fibrillation (AF) is a common complication of heart surgery. Previous studies have shown that there is an association between postoperative AF and prolongation of hospital length of stay. No previous trials have been primarily directed at demonstrating that the use of drugs that prevent AF would shorten length of stay and reduce the costs of postoperative care.

METHODS

A randomized, double-blind, placebo-controlled trial of metoprolol was performed in patients immediately after nonemergent heart surgery. Metoprolol was given orally at a dose of 100 mg per day after the patient's arrival in the intensive care unit until hospital discharge or 14 days, whichever was sooner. This dose was increased to 150 mg per day after the enrollment of 411 patients. The primary outcome measure of the study was hospital length of stay from admission to intensive care unit until hospital discharge. There were 1000 patients enrolled, evenly distributed to the metoprolol and placebo groups.

RESULTS

There was a 20% reduction in the risk of AF developing with metoprolol, from 39% of patients to 31% of patients (P =.01). There was no effect of treatment on hospital length of stay, which was 152 +/- 61 hours for placebo and 155 +/- 90 hours for metoprolol (P = 0.79). The cost of postoperative care in the 2 treatment groups was similar.

CONCLUSION

Prophylactic metoprolol reduces the risk of AF after heart surgery. It does not reduce hospital length of stay. Although it is cost effective for the reduction of AF, it did not reduce the overall cost of care.

Combination of sotalol and magnesium prevents atrial fibrillation after coronary artery bypass grafting

BACKGROUND

Atrial fibrillation (AF) is a common complication reported in 20% to 40% of patients after coronary operations. Sotalol alone and magnesium alone have been shown to partially decrease the incidence of AF. The goal of this study was to evaluate the efficacy of these two pharmacological agents, used alone or in combination, to reduce postoperative AF.

METHODS

Two hundred seven consecutive coronary artery bypass patients (mean age 62 +/- 11 years) were randomized to receive sotalol alone (80 mg twice daily for 5 days starting from the morning of the first postoperative day) (group S), magnesium alone (1.5 g daily for 6 days starting in the operating room just before cardiopulmonary bypass) (group M), both pharmacologic agents at the same dosages (group S+M), or no antiarrhythmic agents (group CTR). All patients with an ejection fraction less than 0.40 were excluded.

RESULTS

The incidence of postoperative AF was 11.8% (6/51) in the S group, 14.8% (8/54) in the M group, 1.9% (1/52) in the S+M group, and 38% (19/50) in the CTR group. The following differences were significant: group CTR versus groups S, M, and S+M with values of p = 0.002, p = 0.007 and p < 0.0001, respectively; and group S+M versus groups S and M with p = 0.04 and p = 0.01, respectively.

CONCLUSIONS

Incidence of AF after coronary operation was significantly reduced by the administration of sotalol alone and magnesium alone; more importantly, the incidence was further reduced by combining these agents.

Interventions on prevention of postoperative atrial fibrillation in patients undergoing heart surgery: a meta-analysis

BACKGROUND

Postoperative atrial fibrillation (AF) is a common complication of cardiac surgery and has been associated with increased incidence of other complications and increased hospital length of stay (LOS). Prevention of AF is a reasonable clinical goal, and, consequently, many randomized trials have evaluated the effectiveness of pharmacological and nonpharmacological interventions for prevention of AF. To better understand the role of various prophylactic therapies against postoperative AF, a systematic review of evidence from randomized trials was performed.

METHODS AND RESULTS

Fifty-two randomized trials (controlled by placebo or routine treatment) of beta-blockers, sotalol, amiodarone, or pacing were identified by systematic literature search. The 3 drug treatments each prevented AF with the following odds ratios (ORs): beta-blockers, 0.39 (95% CI, 0.28 to 0.52); sotalol, 0.35 (95% CI, 0.26 to 0.49); and amiodarone, 0.48 (95% CI, 0.37 to 0.61). Pacing was also effective; for biatrial pacing, the OR was 0.46 (95% CI, 0.30 to 0.71). The influence of pharmacological interventions on LOS was as follows: -0.66 day (95% CI, 2.04 to 0.72) for beta-blockers; -0.40 day (95% CI, 0.87 to 0.08) for sotalol; and -0.91 day (95% CI, 1.59 to -0.23) for amiodarone. The influence for biatrial pacing was -1.54 day (95% CI, -2.85 to -0.24). The incidence of stroke was 1.2% in all the treatment groups combined and 1.4% in controls (OR, 0.90; 95% CI, 0.46 to 1.74).

CONCLUSIONS

Beta-blockers, sotalol, and amiodarone all reduce risk of postoperative AF with no marked difference between them. There is evidence that use of these drugs will reduce LOS. Biatrial pacing is a promising new treatment opportunity. There was no evidence that reducing postoperative AF reduces stroke; however, data on stroke are incomplete.

Amiodarone vs. sotalol as prophylaxis against atrial fibrillation/flutter after heart surgery: a meta-analysis

BACKGROUND

The incidence of supraventricular arrhythmias remains high following open-heart surgery. The most common of these arrhythmias are atrial fibrillation and flutter (AFF), for which treatment is not well defined. Recent studies have focused on prophylactically treating patients in an attempt to reduce postoperative AFF. Several studies have shown that sotalol and amiodarone are both effective in reducing AFF following heart surgery. However, no studies have been done comparing both drugs.

METHODS

A meta-analysis was done to compare the efficacy of sotalol and amiodarone after bypass graft surgery. Randomized controlled trials were included if patients were clearly monitored, and the incidence of AFF was noted. Ten studies were included in the final analysis.

RESULTS

Both amiodarone and sotalol were more effective than placebo treatment in reducing the incidence of postoperative AFF. However, when the data were pooled, no differences were noted between amiodarone and sotalol for efficacy (sotalol, - 21.5%; 95% confidence interval [CI], - 28.3 to - 14.6; amiodarone, - 14.1%; CI, - 20.1 to - 8.1), length of stay (sotalol, - 0.13 d; CI, - 0.33 to 0.07 d; amiodarone, - 0.18; CI, - 0.38 to 0.02 d), or adverse drug reactions causing drug termination (sotalol, 9.7%; CI, 0.086 to 19.3; amiodarone, 1.95%; CI, - 0.48 to 4.38).

CONCLUSIONS

This data would suggest that either drug could be used in a prophylactic regimen to reduce the incidence of AFF following heart surgery.

Current management of symptomatic atrial fibrillation

Atrial fibrillation (AF) is the commonest arrhythmia. It presents in distinct patterns of paroxysmal, persistent and chronic AF, and patient management aims differ according to the pattern. In paroxysmal AF, drug treatment with beta-blockers, class Ic and class III agents reduce the frequency and duration of episodes. In persistent AF (recent onset, non-paroxysmal), early cardioversion with either pharmacological agents or by direct current (DC) cardioversion should be actively considered, in those patients who are suitable. Patients most likely to cardiovert and remain in sinus rhythm include those with duration of AF of <1 year, an acute reversible cause, left atrial diameter <50 mm and good left ventricular function on echocardiography. Recent data show that maintenance of sinus rhythm after successful cardioversion is enhanced by the use of class III drugs including amiodarone and dofetilide. In chronic or permanent AF, management is aimed at controlling the ventricular rate response with combinations of digoxin, beta-blockers and calcium antagonists with atrio-ventricular nodal activity (diltiazem and verapamil). There is some debate about the prognostic significance of AF. Certainly AF is associated with an excess mortality but this is largely accounted for by its association with serious intrinsic heart disease and the thrombo-embolic complications of the arrhythmia. Atrial fibrillation is a common default arrhythmia for the sick heart.

Effect of Sotalol in the prevention of atrial fibrillation following coronary artery bypass grafting

OBJECTIVE

We assessed the efficacy of postoperatively administered oral Sotalol in preventing the occurrence of postoperative atrial fibrillation.

METHODS

Subjects were 80 consecutive patients undergoing coronary artery bypass grafting (CABG) randomized alternately into a Sotalol group (40 patients) administered 80 mg of oral Sotalol daily starting on the postoperative day 1 and continued for 14 days, and a control group (40 patients) matched for age and gender.

RESULTS

The incidence of postoperative atrial fibrillation (21 patients) was significantly lower in the Sotalol group (6/40 patients; 15%) than in controls (15/40; 37.5%) (p < 0.05). Significant bradycardia or hypotension, necessitating drug withdrawal, occurred in 3 of 40 (7.5%) patients in the Sotalol group. None in the Sotalol group developed Torsardes de Pointes or sustained ventricular arrhythmias or other severe side effects. The sinus heart rate increased in both groups but less in the Sotalol group. QT, QRS, and QTc durations did not differ between groups. Postoperative hospital stay did not differ between groups.

CONCLUSIONS

Oral Sotalol administration of 80 mg daily was associated with a significant decrease in postoperative atrial fibrillation in patients undergoing CABG without appreciable side effects. Sotalol should thus be considered in preventing postoperative atrial fibrillation in patients undergoing CABG in the absence of heart failure and significant left ventricular dysfunction.

Predictors of conversion of atrial fibrillation after cardiac operation in the absence of class I or III antiarrhythmic medications

BACKGROUND

Although risk factors for the development of atrial fibrillation (AF) after cardiac operations have been studied extensively, predictors of conversion to sinus rhythm within 24 hours of onset have not been examined.

METHODS

Eleven hundred consecutive adults undergoing cardiovascular operations from July 1997 to June 1998 were screened for new onset AF after operation. Patients with chronic persistent preoperative AF or those who died within 48 hours of the operation were excluded.

RESULTS

Three hundred fifty-three patients develop

Single-day loading dose of oral amiodarone for the prevention of new-onset atrial fibrillation after coronary artery bypass surgery

BACKGROUND

Various regimens have been proposed for the prevention of postoperative atrial fibrillation, including the use of intravenous and oral amiodarone. The purpose of this study was to determine the effectiveness of a single-day loading dose of oral amiodarone in prophylaxis of atrial fibrillation during the 7 days after coronary artery bypass surgery.

METHODS

We conducted a double-blind, randomized, placebo-controlled study encompassing 315 consecutive patients who underwent coronary artery bypass surgery. They received either amiodarone (159 patients) or placebo (156 patients). Therapy consisted of a single oral loading dose of 1200 mg of amiodarone 1 day before surgery, followed by the maintenance dose of 200 mg daily during the next 7 days. Only episodes of atrial fibrillation lasting more than 1 hour or associated with hemodynamic compromise were taken into consideration.

RESULTS

Overall, the incidence of atrial fibrillation was similar in patients who received amiodarone (31/159, 19.5%) and placebo (33/156, 21.2%) (P = .78). However, amiodarone reduced the incidence of atrial fibrillation in elderly patients (age > or = 60 years): it occurred in 20 of 75 (26.7%) patients on amiodarone and in 28 of 65 (43.1%) patients in the placebo group (P = .05). There were no differences between the study groups regarding the postoperative intrahospital morbidity and mortality and the duration of hospital stay.

CONCLUSIONS

A single-day loading dose of oral amiodarone (1200 mg) does not prevent postoperative atrial fibrillation in a general population of patients undergoing coronary artery bypass surgery. However, it appears that this regimen reduces the occurrence of postoperative atrial fibrillation in elderly patients.

Atrial fibrillation after minimally invasive direct coronary artery bypass surgery

OBJECTIVES

The study compared the adjusted risk for developing atrial fibrillation (AF) after minimally invasive direct coronary artery bypass surgery (MIDCAB) and coronary artery bypass graft surgery (CABG).

BACKGROUND

Atrial fibrillation results in increased morbidity and delays hospital discharge after CABG. Recently, MIDCAB has been explored as an alternative to CABG. Because of differences in surgical approach between the two procedures, the incidence of AF may differ.

METHODS

Randomly selected patients undergoing CABG and MIDCAB were examined. Baseline variables and postoperative course were recorded through review of medical record data.

RESULTS

The MIDCAB patients were younger than CABG patients (64+/-12 vs. 67+/-10, p<0.04) and had less extensive coronary artery disease (53% of MIDCAB vs. 3% of CABG had single-vessel disease, while 15% of MIDCAB vs. 69% of CABG had triple-vessel disease, p<0.001 for overall group comparisons). No other differences in clinical or treatment data were noted. Postoperative AF occurred less often after MIDCAB (23% vs. 39%, p = 0.02). Other significant factors associated with postoperative AF included age (p = 0.0024), prior AF (p = 0.0007), left main disease (p = 0.01), number of vessels bypassed (p = 0.009), absence of postoperative beta-blocker therapy (p = 0.0001), and a serious postoperative complication (p = 0.0018). Because of differences between CABG and MIDCAB patients, multivariate logistic analysis was performed to determine independent predictors of postoperative AF. The type of surgery (CABG vs. MIDCAB) was no longer a significant predictor of postoperative AF (estimated relative risk for AF in CABG vs. MIDCAB patients: 1.57, 95% confidence interval (0.82-2.52).

CONCLUSIONS

Although AF appears to be less common after MIDCAB than after CABG, the lower incidence is due to different clinical characteristics of patients undergoing these procedures.

Intravenous amiodarone or magnesium sulphate is not cost-beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery

Our aims were to examine whether the administration of amiodarone or magnesium sulphate after coronary artery bypass graft surgery (CABG) could reduce the occurrence of atrial fibrillation, and to identify the risk factors associated with atrial fibrillation after CABG. Patients scheduled for elective CABG (n = 155) were allocated randomly, in a controlled double-blind study, to receive immediately after surgery a 72-h infusion of amiodarone (900 mg per 24 h), magnesium (4 g per 24 h) or placebo (0.9% NaCl; 50 ml per 24 h) intravenously. A 72-h Holter ECG was recorded concomitantly. The primary end-point was the prevention of atrial fibrillation; its onset was considered as prophylactic failure. An interim safety analysis was performed in 147 patients. The cumulative occurrence of atrial fibrillation was 27% in the placebo group, 14% in the amiodarone group (P = 0.14) and 23% in the magnesium group (P = 0.82). Although amiodarone delayed the onset of the first tachyarrhythmic episode (P = 0.02), it was associated with the need for longer periods of vasoactive drug infusion and invasive monitoring and a longer stay in the intensive care unit. Variables associated with the onset of atrial fibrillation were older age (odds ratio 1.9) and a plasma magnesium concentration at 24 h of less than 0.95 mmol litre-1 (odds ratio 6.7). Postoperative administration of amiodarone reduced the occurrence of atrial fibrillation after elective CABG surgery, but was associated with a longer duration of cardiovascular instability and longer need for intensive care; magnesium prophylaxis had no effect. Advanced age and a low plasma magnesium concentration are risk factors for postoperative atrial fibrillation.

Randomized controlled study investigating the effect of biatrial pacing in prevention of atrial fibrillation after coronary artery bypass grafting

BACKGROUND

Atrial fibrillation (AF) is a common problem after CABG. Prevention with prophylactic drug therapy has had limited success, therefore alternative approaches are required. This study investigated the role of biatrial pacing compared with no pacing on AF incidence after isolated first-time CABG.

METHODS AND RESULTS

During surgery, temporary pacing leads were placed in the lateral wall of the right atrium and at the roof of the left atrium in Bachmann's bundle to allow bipolar pacing and sensing at each site. After surgery, all patients were connected to an external pacemaker (Chorum ELA) that also acted as a Holter monitor. Patients were consecutively randomized to either 4 days of biatrial pacing at a base rate of 80 bpm or to no pacing (control group, base rate 30 bpm). End points included an episode of AF lasting >1 hour on pacemaker Holter, clinically detected AF, intensive care unit (ICU) and hospital stay, and postoperative complications. One hundred thirty patients were randomized. Biatrial pacing significantly reduced both monitored (13.8% versus 38.5%, P:=0.001) and clinical (10.8% versus 33.8%, P:=0.002) episodes of AF. Median ICU (19 versus 24 hours, P:=NS) and mean hospital stay (7.7+/-6.9 versus 9.7+/-10, P:=NS) did not significantly change. The number of postoperative complications was lower in the biatrial group (13 versus 35, P:=0. 001).

CONCLUSIONS

Biatrial pacing after CABG significantly decreases the incidence of AF. This is associated with reduced postoperative complications and a trend toward reduced ICU and hospital stay.

Prophylaxis of supraventricular and ventricular arrhythmias after coronary artery bypass grafting with low-dose sotalol

BACKGROUND

Supraventricular tachyarrhythmia (SVT) commonly occurs shortly after coronary artery bypass grafting (CABG), but ventricular arrhythmias are less documented.

METHODS

On the 1st postoperative day, 206 consecutive eligible patients were prospectively randomized to a sotalol group (80 mg b.i.d.; n = 103) or a control group without beta-blockade or antiarrhythmic drugs (n = 103).

RESULTS

The SVT incidence (predominantly atrial fibrillation) accounted for 16% in the sotalol group versus 48% (p < 0.00001). Multivariate analysis showed that sotalol reduced the SVT incidence (p < 0.00001, odds ratio, 0.20; 95% confidence interval, 0.09 to 0.42), whereas a lower preoperative left ventricular ejection fraction (p = 0.019) and older age (p = 0.031) were independent risk factors of SVT occurrence. The Holter electrocardiographic analysis (24 hours) demonstrated that sotalol (32 versus 92; p = 0.031) decreased the median number of ventricular events, mostly isolated premature ventricular beats. Neither ventricular proarrhythmia effect nor "torsades de pointes" were detected. Despite strict hemodynamic-based selection, sotalol had to be discontinued in 8 patients (7.8%), for reasons related to asthma in 3 or cardiac reasons in 5.

CONCLUSIONS

Oral low-dose sotalol provided considerable and reliable protection in selected nondepressed cardiac function patients, reducing the occurrence of both supraventricular and ventricular arrhythmias after CABG.

Management and prevention of atrial fibrillation after cardiovascular surgery

Atrial arrhythmias occur frequently after cardiac surgery. This article discusses the incidence of postoperative atrial arrhythmia as well as its prognosis, potential mechanisms of pathogenesis, and management. Prophylactic therapy for postoperative atrial arrhythmia is recommended because of the frequency of occurrence and the ease with which therapies can often be implemented. Treatments with pharmacologic and nonpharmacologic modalities are described. Management strategies for atrial arrhythmias that occur postoperatively, including pharmacologic and nonpharmacologic measures as well as anticoagulation recommendations, are discussed.

Drug choices in the treatment of atrial fibrillation

When considering therapy for atrial fibrillation (AF), the dominant issues are rate control, anticoagulation, rhythm control, and treatment of any underlying disorder. Drug choices for rate control include beta-blockers, verapamil and diltiazem, and digitalis as first-line agents, with consideration of other sympatholytics, amiodarone, or nonpharmacologic approaches in resistant cases. Anticoagulation may be accomplished with aspirin or warfarin, with the latter preferred in all older or high-risk patients. Antiarrhythmic drug therapy may be used (1) to produce cardioversion (most effective with ibutilide or class IC agents in recent onset AF); (2) to facilitate electrical conversion (class III agents); (3) to prevent early reversion after cardioversion; (4) to maintain sinus rhythm during chronic therapy; and/or (5) to facilitate conversion of fibrillation to flutter, which may then be amenable to termination or prevention with antitachypacing or ablative techniques. Antiarrhythmic drug selection for AF is guided by efficacy considerations (most drugs are similar), by convenience, cost, and discontinuation considerations; and, most importantly, by safety considerations. When possible, agents with serious organ toxicity potential and proarrhythmic risk should be avoided as first-line choices. In structurally normal hearts, class IC antiarrhythmic drugs are least proarrhythmic and least organ toxic (when considered together). In normal hearts, sotalol, dofetilide, and potentially azimilide also appear to have attractive profiles. Amiodarone has low proarrhythmic risk but can produce bradyarrhythmias and toxicity. In hypertrophied hearts, the risk of torsade de pointes with class III/IA agents is enhanced, whereas in ischemia or conditions with impaired cell contact, whether functionally (as by ischemia) or anatomically (as by fibrosis, infiltration, etc), proarrhythmic risk with class I antiarrhythmic drugs (sustained ventricular fibrillation/flutter) is greatly increased. The class I drugs should be avoided in these circumstances. Additional issues to consider are where to initiate therapy (in- or outpatient), what follow-up protocols to use, and whether to limit therapy to proprietary drugs or to allow generic formulation substitution. Each of these considerations is detailed in this article.

Appropriate outcome measures in trials evaluating treatment of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a widespread disease that has only recently received the focused attention of arrhythmia specialists despite being the most frequently occurring significant cardiac arrhythmia.

METHODS AND RESULTS

The wide variety of trial designs used to evaluate AF treatment is a reflection of the diverse outcomes associated with this condition. The best trials assess the impact of treatment on a clearly measured outcome that is of clinical relevance to patients. This review discusses the different designs of AF treatment trials and analyzes the utility of the various outcomes that can be assessed.

CONCLUSIONS

A sensible goal of AF treatment is to reduce the frequency of recurrences and to prolong the time between them. The most appropriate trials focus on AF recurrences that are symptomatic and therefore relevant to the patient. We still do not know if there is value in AF prevention, beyond preventing symptoms. However, ongoing and future studies will show whether AF suppression reduces the longer-term risks of stroke or death and improves patient quality of life. Cost of care will increasingly be studied in future trials of AF management.

Atrial fibrillation after coronary artery bypass surgery: a model for preoperative risk stratification

BACKGROUND

Atrial fibrillation (AF) occurs in 20% to 40% of patients after CABG. Identification of patients vulnerable for arrhythmia will allow targeting of those most likely to benefit from prophylactic therapy. The aim of the present study was to evaluate accuracy of a prospectively defined signal-averaged P-wave duration (SAPD) cutoff and additional preoperative characteristics for the prediction of AF after CABG.

METHODS AND RESULTS

Patients undergoing elective isolated CABG were recruited to the present prospective study. SAPD was recorded in all patients. Filtered signals from 3 orthogonal leads were combined in a vector analysis, and total SAPD was measured preoperatively. Postoperative in-hospital AF occurred in 92 (28.2%) of 326 patients. Patients who developed AF were older (65.9 versus 61.7 years of age; P<0.0005) and had longer SAPD (158 versus 145 ms; P<0.0005) than non-AF patients. Incidence of AF increased in patients > or =75 years of age and increased progressively throughout the range of SAPD. Stepwise logistic regression analysis of preoperative variables identified that SAPD >155 ms (odds ratio, 5.37; 95% CI, 3.10 to 9.30; P<0.0005), advanced age (odds ratio, 1. 53; 95% CI, 1.26 to 1.86 per 5-year increase in age; P<0.0005), and male sex (odds ratio, 2.88; 95% CI, 1.30 to 6.40; P<0.01) independently predicted AF. Prospectively defined SAPD >155 ms predicted AF with positive and negative predictive accuracy of 49% and 84%, respectively.

CONCLUSIONS

A combination of prolonged SAPD, advanced age, and male sex identifies patients at high risk for development of AF after CABG.

Review of methods to predict and detect atrial fibrillation in post-cardiac surgery patients

Atrial fibrillation (AF) is the most common sustained arrhythmia after cardiac surgery. Postoperative AF is known to substantially lengthen hospital stay and affect patient recovery. Identification of those at risk of developing AF after surgery and early detection of AF during recovery would be extremely helpful in effective management of these patients, including targeting prophylactic therapy to prevent AF in high-risk patients. In this communication, diagnostic methods to identify those at risk of developing AF after surgery and early identification of AF before, during, and after surgery have been reviewed. Signal-averaged P wave analysis, done before surgery, identifies patients who are likely to develop AF during recovery. When combined with low ejection fraction, signal-averaged P wave can discriminate those who develop AF from those who do not. During recovery, AF can be detected early either from a detailed analysis of atrial activity in a 10-second electrocardiogram or an analysis of R-to-R intervals from an extended rhythm strip (1 minute or longer). Analysis of the 10-second electrocardiogram includes median QRST subtraction from rhythm data and detection and analysis of atrial signals in the resulting residual. AF is detected from extended rhythm strips by using a statistical model to identify the presence of characteristic irregular patterns of R-to-R intervals.

Atrial fibrillation after cardiac operation: risks, mechanisms, and treatment

Atrial fibrillation (AF) is a common complication of cardiac operations that leads to increased risk for thromboembolism and excessive health care resource utilization. Advanced age, previous AF, and valvular heart operations are the most consistently identified risk factors for this arrhythmia. Dispersion of repolarization leading to reentry is believed to be the mechanism of postoperative AF, but many questions regarding the pathophysiology of AF remain unanswered. Treatment is aimed at controlling heart rate, preventing thromboembolic events, and conversion to sinus rhythm. Multiple investigations have examined methods of preventing postoperative AF, but the only firm conclusions that can be drawn is to avoid beta-blocker withdrawal after operation and to consider beta-blocker therapy for other patients who may tolerate these drugs. Preliminary investigations showing sotalol and amiodarone to be effective in preventing postoperative AF are encouraging, but early data have been limited to selective patient populations and have not adequately evaluated safety. Newer class III antiarrhythmic drugs under development may have a role in the treatment of postoperative AF, but the risk of drug-induced polymorphic ventricular tachycardia must be considered. Nonpharmacologic interventions under consideration for the treatment of AF in the nonsurgical setting, such as automatic atrial cardioversion devices and multisite atrial pacing, may eventually have a role for selected cardiac surgical patients.

Prevention of atrial fibrillation in the postoperative cardiac patient: significance of oral class III antiarrhythmic agents

Atrial fibrillation is a frequent complication of cardiac surgery and the most common reason for delay in discharge from the hospital after open-heart surgery. This review summarizes the results of studies that have examined the prophylactic value of orally administered sotalol and amiodarone in preventing atrial fibrillation after open-heart surgery. The reduction in the prevalence of postoperative atrial fibrillation is 50-90% for sotalol compared with 50-60% for amiodarone. Sotalol has a rapid onset of action, allowing it to be efficacious when used orally shortly after surgery. In contrast, amiodarone has a slow onset of action that necessitates either oral loading for several days before surgery or intravenous loading shortly before or after surgery. However, although patients who are poor candidates for beta blockade may not tolerate sotalol, amiodarone does not have this limitation. Although both sotalol and amiodarone have relative advantages and disadvantages, available data indicate that either agent can be used effectively in selected patients to reduce the risk of postoperative atrial fibrillation. Larger controlled comparative trials are needed to define the precise magnitude of benefit from these compounds relative to their side effect profiles.

Oral d,l sotalol reduces the incidence of postoperative atrial fibrillation in coronary artery bypass surgery patients: a randomized, double-blind, placebo-controlled study

OBJECTIVES

The purpose of this prospective, randomized, double-blind, placebo-controlled study was to assess the efficacy of preoperatively and postoperatively administered oral d,l sotalol in preventing the occurrence of postoperative atrial fibrillation (AF).

BACKGROUND

Atrial fibrillation is the most common arrhythmia following coronary artery bypass surgery (CABG). Its etiology, prevention and treatment remain highly controversial. Furthermore, its associated morbidity results in a prolongation of the length of hospital stay post-CABG.

METHODS

A total of 85 patients, of which 73 were to undergo CABG and 12 CABG plus valvular surgery (ejection fraction > or = 28% and absence of clinical heart failure), were randomized to receive either sotalol (40 patients; mean dose = 190 +/- 43 mg/day) started 24 to 48 h before open heart surgery and continued for four days postoperatively, or placebo (45 patients, mean dose = 176 +/- 32 mg/day).

RESULTS

Atrial fibrillation occurred in a total of 22/85 (26%) patients. The incidence of postoperative AF was significantly (p = 0.008) lower in patients on sotalol (12.5%) as compared with placebo (38%). Significant bradycardia/hypotension, necessitating drug withdrawal, occurred in 2 of 40 (5%) patients on sotalol and none in the placebo group (p = 0.2). None of the patients on sotalol developed Torsade de pointes or sustained ventricular arrhythmias. Postoperative mortality was not significantly different in sotalol versus placebo (0% vs. 2%, p = 1.0). Patients in the sotalol group had a nonsignificantly shorter length of hospital stay as compared with placebo (7 +/- 2 days vs. 8 +/- 4 days; p = 0.24).

CONCLUSIONS

The administration of sotalol, in dosages ranging from 80 to 120 mg, was associated with a significant decrease (67%) in postoperative AF in patients undergoing CABG without appreciable side effects. Sotalol should be considered for the prevention of postoperative AF in patients undergoing CABG in the absence of heart failure and significant left ventricular dysfunction.

Intravenous amiodarone for the prevention of atrial fibrillation after open heart surgery: the Amiodarone Reduction in Coronary Heart (ARCH) trial

OBJECTIVES

This study was designed to test whether intravenous (i.v.) amiodarone would prevent atrial fibrillation and decrease hospital stay after open heart surgery.

BACKGROUND

Atrial fibrillation commonly occurs after open heart procedures and is thought to be a significant determinant for prolongation of hospitalization. Oral amiodarone given preoperatively appears to reduce the incidence of atrial fibrillation. This study was designed to test whether the more rapid-acting i.v. formulation of amiodarone given postoperatively would reduce the incidence of atrial fibrillation.

METHODS

Three hundred patients undergoing standard open heart surgery were randomized in a double-blind fashion to i.v. amiodarone (1 g/day for 2 days) versus placebo immediately after open heart surgery. The primary end points of the trial were incidence of atrial fibrillation and length of hospital stay. Baseline clinical variables and mortality and morbidity data were collected.

RESULTS

Atrial fibrillation occurred in 67/142 (47%) patients on placebo versus 56/158 (35%) on amiodarone (p = 0.01). Length of hospital stay for the placebo group was 8.2 +/- 6.2 days, and 7.6 +/- 5.9 days for the amiodarone group (p = 0.34). No differences were noted in baseline variables, morbidity or mortality.

CONCLUSIONS

Low-dose i.v. amiodarone was safe and effective in reducing the incidence of atrial fibrillation after heart surgery, but did not significantly alter length of hospital stay.

Prophylactic oral amiodarone compared with placebo for prevention of atrial fibrillation after coronary artery bypass surgery

BACKGROUND

Postoperative atrial fibrillation occurs in 20% to 40% of patients undergoing coronary artery bypass grafting (CABG) and contributes to delayed recovery, increased length of stay, and increased hospital cost. Measures at preventing postoperative atrial fibrillation have had mixed results. We report a double-blind trial comparing oral amiodarone with placebo for the prevention of atrial fibrillation after CABG.

METHODS AND RESULTS

All patients undergoing CABG were considered eligible. Exclusion criteria included bradycardia (<50 beats/min), prior Atrial fibrillation, concurrent therapy with antiarrhythmic drugs, or concomitant valve surgery. Patients were given 2 g of amiodarone (73 patients) or placebo (70 patients) in divided doses 1 to 4 days before surgery and 400 mg daily for 7 days postoperatively. Atrial fibrillation occurred in 24.7% (18 of 43) of patients receiving amiodarone and 32. 8% (23 of 70) of patients receiving placebo (P =.30). Heart rate at onset of atrial fibrillation was 133.4 +/- 26.6 beats/min for amiodarone compared with 152.9 +/- 31.6 beats/min for placebo (P =. 04). Duration of atrial fibrillation was 10.2 +/- 8.1 hours for amiodarone compared with 16.2 +/- 27.5 hours for placebo (P =.67). Patients receiving both beta-blockade and amiodarone had a 16.7% incidence of atrial fibrillation compared with 31.9% in the remaining patients (P =.10). Atrial fibrillation was associated with an increased cost of $7011 compared with those who remained in sinus rhythm ($23,869 +/- $20,894 vs $16,857 +/- $5401 in sinus rhythm). Hospital cost of those taking amiodarone was $18,895 +/- $13,267 compared with $18,839 +/- $11,537.18 for placebo (P =.42).

CONCLUSION

Postoperative CABG atrial fibrillation is associated with prolonged hospital stay and increased cost. Prophylactic oral amiodarone did not statistically alter the incidence or duration of atrial fibrillation after CABG, although favorable trends were noted. Hospital cost was not affected by therapy with amiodarone.

Sotalol: An important new antiarrhythmic

Sotalol, the most recently approved oral antiarrhythmic drug, has a unique pharmacologic profile. Its electrophysiology is explained by nonselective beta-blocking action as well as class III antiarrhythmic activity (including fast-activating cardiac membrane-delayed rectifier current blockade), which leads to increases in action potential duration and refractory period throughout the heart and in QT interval on the surface electrocardiogram. Its better hemodynamic tolerance than other beta-blockers may be a result of enhanced inotropy associated with class III activity. Sotalol's ability to suppress ventricular ectopy is similar to that of class I agents and better than that of standard beta-blockers. Unlike class I agents, its use in a postinfarction trial was not associated with increased mortality rate. Therapeutically, it has shown superior efficacy for prevention of recurrent ventricular tachycardia and ventricular fibrillation, which was the basis for its approval. In a randomized study, the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, sotalol was associated with an increased in-hospital efficacy prediction rate (by Holter monitor or electrophysiologic study), reduced long-term arrhythmic recurrence rate with superior tolerance, and lower mortality rate than class I ("standard") antiarrhythmic drugs. Sotalol was 1 of 2 drugs selected for comparison with implantable defibrillators in the recent National Institutes of Health Antiarrhythmics versus Implantable Defibrillator (AVID) study. Sotalol appears to be a preferred drug for use with implantable defibrillators; unlike some other agents (eg, amiodarone) it does not elevate and, indeed, may lower defibrillation threshold. Although unapproved for this use, sotalol is active against atrial arrhythmias. It has shown efficacy equivalent to propafenone and quinidine in preventing atrial fibrillation recurrence, but it is better tolerated than quinidine and provides excellent rate control during recurrence. Sotalol's major side effects are related to beta-blockade and the risk of torsades de pointes (acceptably small if appropriate precautions are taken). Unlike several other antiarrhythmics (eg, amiodarone), it has no pharmacokinetic drug-drug interactions, is not metabolized, and is entirely renally excreted. Initial dose is 80 mg twice daily, with gradual titration to 240 to 360 mg/day as needed. The daily dose must be reduced in renal failure. On the basis of favorable clinical trials and practice experience, sotalol has shown a steadily growing impact on the treatment of arrhythmias during its 5 years of market availability, a trend that is likely to continue.