ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation

Concomitant ablation of atrial fibrillation in octogenarians: an observational study

BACKGROUND

Cardiac surgery is increasingly required in octogenarians. These patients frequently present atrial fibrillation (AF), a significant factor for stroke and premature death. During the last decade, AF ablation has become an effective procedure in cardiac surgery. Because the results of concomitant AF ablation in octogenarians undergoing cardiac surgery are still not clear, we evaluated the outcome in these patients.

METHODS

Among 200 patients undergoing concomitant AF ablation (87% persistent AF), 28 patients were >/= 80 years (82 +/- 2.4 years). The outcome was analysed by prospective follow up after 3, 6, 12 months and annually thereafter. Freedom from AF was calculated according to the Kaplan-Meier method.

RESULTS

Octogenarians were similar to controls regarding AF duration (48 +/- 63.2 versus 63 +/- 86.3 months, n.s.) and left atrial diameter (49 +/- 6.1 versus 49 +/- 8.8 mm, n.s.), but differed in EuroSCORE (17.3 +/- 10.93 versus 7.4 +/- 7.31%, p < 0.001), prevalence of paroxysmal AF (25.0 versus 11.0%, p = 0.042) and aortic valve disease (67.8 versus 28.5%, p < 0.001). ICU stay (8 +/- 16.9 versus 4 +/- 7.2 days, p = 0.027), hospital stay (20 +/- 23.9 versus 14 +/- 30.8 days, p < 0.05), and 30-d-mortality (14.3 versus 4.6%, p = 0.046) were increased. After 12 +/- 6.1 months of follow-up (95% complete), 14 octogenarians (82%) and 101 controls (68%, n.s.) were in sinus rhythm; 59% without antiarrhythmic drugs in either group (n.s.). Sinus rhythm restoration was associated with improved NYHA functional class and renormalization of left atrial size. Cumulative freedom from AF demonstrated no difference between groups. Late mortality was higher in octogenarians (16.7 versus 6.1%, p = 0.065).

CONCLUSION

Sinus rhythm restoration rate and functional improvement are satisfactory in octogenarians undergoing concomitant AF ablation. Hence, despite an increased perioperative risk, this procedure should be considered even in advanced age.

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.

Short-term effects of cilazapril and atenolol on P-wave dispersion in patients with hypertension

INTRODUCTION

P-wave dispersion (PWD) has been shown to be a non-invasive electrocardiographic predictor for development of atrial fibrillation (AF). Thus, it may be possible to decrease AF risk through improvement in PWD. Our objective was to compare the effects of cilazapril and atenolol on P-wave duration and dispersion in patients with hypertension.

METHODS

A total of 38 newly diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either cilazapril (5 mg) or atenolol (50 mg). Doppler echocardiographic examination, P-wave durations and PWD were measured before and 1 mo after treatment

RESULTS

Both drugs reduced blood pressure significantly (P<0.001). Posttreatment heart rate was significantly lower in the atenolol group (P=0.01). The change in maximum P-wave duration was not significant. However, both agents decreased PWD (P=0.001 and P<0.001) and increased the minimum P-wave duration (P=0.004 and P=0.02).

CONCLUSION

Both cilazapril and atenolol treatments resulted in improvement in PWD.

Artificial muscles to restore transport function of diseased atria

Surgical treatment of persistent atrial fibrillation often fails to restore the transport function of the atrium. This study first introduces the concept of an atrial assist device to restore the pump function of the atrium. A micro motorless pump based on artificial muscle technology, is positioned on the external surface of the atrium to compress it and restore its muscular activity. A bench model reproduces the function of fibrillating atrium to assess the circulatory support that this pump can provide. The Atripump is a dome shape silicone coated nitinol actuator mounted on a plastic ring. A pacemaker-like control unit drives the actuator, which compresses the atrium, providing the mechanical support to the blood circulation. The bench model consists of an open circuit made of latex bladder 60 mm in diameter filled with water. The Atripump is placed on the outer surface of the bladder. Pressure, volume, and temperature changes were recorded. The contraction rate was 1 Hz with power supply of 12 V, 400 mA for 200 milliseconds. Preload ranged from 15 to 21 cm H20. The pump produced a maximal work of 16 x 10(-3) J. Maximal volume pumped was 492 ml/min. This artificial muscle pump is compact, and reproduces the hemodynamic performances of normal atrium.

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.

Catheter ablation of atrial fibrillation

Atrial fibrillation is a common arrhythmia associated with significant morbidity including angina, heart failure and stroke. Medical therapy remains suboptimal with significant side effects and toxicities, as well as a high recurrence rate. Catheter ablation or modification of the atrio-ventricular node with pacemaker implantation provides rate control but subjects the patient to the risks of an implantable device and does nothing to reduce the risk of stroke. Pulmonary vein antrum isolation offers a nonpharmacologic means of restoring sinus rhythm, thereby eliminating the morbidity of atrial fibrillation and the need for anti-arrhythmic drugs.

Emergency department use of intravenous procainamide for patients with acute atrial fibrillation or flutter

OBJECTIVES

Acute atrial fibrillation and flutter are very common arrhythmias seen in emergency department (ED) patients, but there is no consensus for their optimal management. The objective of this study was to examine the efficacy and safety of intravenous (IV) procainamide for acute atrial fibrillation or flutter.

METHODS

This health records review included a consecutive cohort of ED patients with acute-onset atrial fibrillation or atrial flutter who received IV procainamide at one university hospital ED during a five-year period. The standard clinical protocol involved IV infusion of 1 g of procainamide over 60 minutes, followed by electrical cardioversion if necessary. A trained observer extracted data from the original clinical records. Outcome measurements included conversion to sinus rhythm, adverse events, and relapse up to seven days.

RESULTS

The 341 study patients had a mean age of 63.9 years (SD +/- 15.5 years), and 56.6% were male. The conversion rates were 52.2% (95% confidence interval = 47% to 58%) for 316 atrial fibrillation cases and 28.0% (95% confidence interval = 13% to 46%) for 25 atrial flutter cases. Mean dose given was 860.7 mg (SD +/- 231.2 mg), and median time to conversion was 55 minutes. Adverse events occurred in 34 cases (10.0%): hypotension, 8.5%; bradycardia, 0.6%; atrioventricular block, 0.6%; and ventricular tachycardia, 0.3%. There were no cases of torsades de pointes, cerebrovascular accident, or death. Most patients (94.4%) were discharged home, but 2.9% of patients returned with a recurrence of atrial fibrillation within seven days.

CONCLUSIONS

This study of acute atrial fibrillation or flutter patients treated in the ED with IV procainamide suggests that this treatment is safe and effective in this setting. Procainamide should be prospectively compared with other ED strategies.

The incidence of ischemic stroke in chronic heart failure: a meta-analysis

BACKGROUND

There is marked variability in the reported stroke rates among persons with heart failure (HF). We performed a meta-analysis to provide summary estimates of the stroke rate in HF and to explain heterogeneity in the existing literature. We will summarize the ischemic stroke rate at various time points during follow-up among adults with chronic heart failure.

METHODS AND RESULTS

A systematic review of the electronic literature in Medline and PubMed as well as hand searching of the reference lists of identified articles and of the meeting abstracts for the 1995-2004 American College of Cardiology and American Heart Association scientific sessions was performed to identify qualifying studies. Articles were included if they included a population with chronic HF and reported the number (or percent) of persons with HF who experienced an ischemic stroke during follow-up. Studies were excluded if the study population included > or = 50% of persons with acute (postmyocardial infarction) HF, or if > or = 50% of the study population required artificial support with a ventricular assist device or parenteral inotropic medications. Case reports, case series, and nonoriginal research articles were not included. Determination of study eligibility and data extraction were conducted by 2 independent reviewers using standardized forms. Results are reported as stroke rate per 1000 cases of HF, with 95% Poisson confidence intervals. Pooled estimates of the stroke rate were calculated with fixed and random effects models. Heterogeneity was explored according to a priori specified subgroup analyses. Overall, 26 studies met inclusion criteria. Eighteen of every 1000 persons suffered a stroke during the first year after the diagnosis of HF. The stroke rate increased to a maximum of 47.4 per 1000 at 5 years. Studies with fewer women, those conducted in 1990 or earlier, and cohort studies reported higher stroke rates than studies with more women, those conducted after 1990, and clinical trials.

CONCLUSIONS

Stroke is an important complication among persons with HF. Variability among reported stroke rates can be explained in part by differences in study design, patient population, and HF standards of care at the time of the study. Despite the heterogeneity in reported stroke rates, this meta-analysis shows that stroke prevention in HF represents an opportunity to prevent morbidity and save many lives in this highly fatal disease.

Surgical Ablation of Atrial Fibrillation in Patients With Congestive Heart Failure

BACKGROUND

Congestive heart failure (CHF) and atrial fibrillation (AF), both of which cause morbidity and mortality, are mutually promoting diseases. We aimed to evaluate surgical AF ablation in CHF.

METHODS AND RESULTS

Among 212 patients (age 69 +/- 8.8 years, 87% with persistent AF) undergoing concomitant left atrial (LA) ablation, 79 (37.3%) presented CHF (n = 62 with a left ventricular ejection fraction [LVEF] 0.31-0.45, n = 17 with an LVEF < or = 0.30). Patients with CHF were similar to controls regarding AF duration (61 +/- 65.1 months vs. 54 +/- 67.2 months, not significant [NS]), LA diameter (49 +/- 7.5 mm vs. 50 +/- 9.2 mm, NS), and heart rate (78 +/- 18.4 min(-1) vs. 81 +/- 21.3 min(-1), NS), but they required more circulatory support (17.7% vs. 1.5%, P < .001) and a longer intensive care unit stay (6 +/- 9.5 days vs. 4 +/- 10.5 days, P = .032). At follow-up after 13 +/- 7.3 months, 42 patients (66%) with CHF and 81 controls (74%, NS) were in sinus rhythm (SR) (55% and 64% without antiarrhythmic drugs, respectively, NS). Univariate and logistic regression analysis revealed that AF duration and LA diameter predicted rhythm outcome but not CHF. In patients with an LVEF of 0.30 or less, SR conversion significantly improved LVEF, New York Heart Association class, and Minnesota Living with Heart Failure score. Kaplan-Meier estimates suggested superior survival of patients with stable SR (100% vs. 73%, log-rank P < .05).

CONCLUSIONS

If patients presenting with CHF and AF require cardiac surgery, concomitant AF ablation should be considered, especially if left ventricular function is severely impaired.

The effect of angiotensin receptor blockers for preventing atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia in clinical practice, and causes significant burden to patients and health care systems. Clinicians treat existing atrial fibrillation with anticoagulation and/or drugs that utilize either a rate or rhythm control strategy. It remains unclear how best to reduce cardiovascular morbidity and mortality in this population. Prevention of atrial fibrillation using angiotensin receptor blockers, which affect ion currents and refractoriness in atrial myocytes, regress or prevent atrial fibrosis, decrease left atrial size, regress left ventricular hypertrophy, modulate sympathetic nerve activity, reduce inflammation, and reduce blood pressure, may become an important and desirable alternative.

Racial/ethnic differences in the risk of intracranial hemorrhage among patients with atrial fibrillation

OBJECTIVES

This study was designed to study racial/ethnic differences in the risk for intracranial hemorrhage (ICH) and the effect of warfarin on ICH risk among patients with atrial fibrillation (AF).

BACKGROUND

Nonwhites are at greater risk for ICH than whites in the general population. Whether this applies to patients with AF and whether warfarin therapy is associated with comparable risk of ICH in nonwhites are unknown.

METHODS

We retrospectively identified a multiethnic stroke-free cohort hospitalized with nonrheumatic AF. Warfarin use and anticoagulation intensity were assessed by searching pharmacy and laboratory records. Crude ICH event rates were calculated by Poisson regression. Cox proportional hazard models were constructed to assess the independent effect of race/ethnicity on ICH after adjusting for age, gender, hypertension, diabetes, heart failure, and warfarin exposure.

RESULTS

Between 1995 and 2000, we identified 18,867 qualifying AF hospitalizations (78.5% white, 8% black, 9.5% Hispanic, and 3.9% Asian) and 173 qualifying ICH events over 3.3 years follow-up. Achieved anticoagulation intensity was lower among blacks but not different between the other groups. Warfarin was associated with increased ICH risk in all races, but the magnitude of risk was greater among nonwhites. There were no gender differences. The hazard ratio for ICH with whites as referent was 4.06 for Asians (95% confidence interval [CI] 2.47 to 6.65), 2.06 for Hispanics (95% CI 1.31 to 3.24), and 2.04 (95% CI 1.25 to 3.35) for blacks.

CONCLUSIONS

Nonwhites with AF were at greater risk for warfarin-related ICH. Blacks, Hispanics, and Asians were at successively greater ICH risk than whites.

Adjunctive Procedures in Degenerative Mitral Valve Repair: Tricuspid Valve and Atrial Fibrillation Surgery

Tricuspid regurgitation (TR) and atrial fibrillation (AF) are frequently encountered in patients with myxomatous mitral valve disease. Recent publications have indicated the seriousness of untreated TR, even in those with no TR but only annular dilation. If left untreated, the patients with annular dilation without TR were more prone to develop TR during follow-up and had worse New York Heart Association functional class. At the Bluhm Cardiovascular Institute, 39% of patients who had mitral valve surgery had a history of AF. This included 54.4% of patients who were undergoing a re-operation. Five randomized, prospective clinical trials have documented that patients with permanent AF who undergo mitral valve surgery are far more likely to return to sinus rhythm if AF is treated with ablation at the same time as the mitral valve operation. For the group of patients with permanent AF, sinus rhythm was restored in only 5% to 33% of patients in the control group versus 44% to 93% of those in whom ablation was applied. A variety of technologies are available to ablate AF. The basic lesion must electrically isolate the pulmonary veins. For patients with permanent AF, there is evidence that a connecting lesion to the mitral valve annulus will increase success and that biatrial lesion sets will provide the best long-term freedom from AF.

Guidelines for reporting data and outcomes for the surgical treatment of atrial fibrillation

Atrial fibrillation is the most common sustained cardiac rhythm disturbance, affecting an estimated 2.5 million people in the United States. Atrial fibrillation may occur with or without structural heart disease. The medical and surgical literature has seen an exponential growth in reports of ablation techniques and the Cox-Maze procedure to treat atrial fibrillation. There has been no agreement or standards on the proper reporting of these techniques and results. The current literature is in disarray, and this report is an attempt to provide a framework for the necessary elements to be included in reports on this subject. The Workforce on Evidence Based Surgery of the Society of Thoracic Surgeons encourages the adoption of these guidelines for reporting clinical results derived from patients undergoing surgical procedures for atrial fibrillation. Adoption of these guidelines will greatly facilitate the comparison between the reported experiences of various authors treating different cohorts of patients at different times with different techniques and energy sources. These guidelines are also appropriate for catheter-based treatment of atrial fibrillation. Thus, more reliable evaluation and comparisons of results will advance our knowledge and further the development and application of these procedures.

Do we need pharmacological therapy for atrial fibrillation in the ablation era?

Management of atrial fibrillation (AF) remains one of the most difficult problems of modern cardiology. Pharmacological antiarrhythmic therapy is used both for termination of episodes of AF and for prevention of AF recurrences. Recently, major trials have compared the strategy of maintenance of sinus rhythm, called rhythm control, with the strategy of heart rate control during AF and found that the rhythm control strategy was not superior to rate control in terms of mortality. Although subsequent analysis identified rhythm control as a factor of improved survival, these large trials have markedly influenced the management of AF. One of the hypotheses explaining the non-superiority of the rhythm control strategy was that the benefit of sinus rhythm was offset by the side effects of antiarrhythmic agents. As a consequence, attention was directed to non-pharmacological therapies, particularly to catheter ablation of the trigger or/and the atrial substrate using radiofrequency current or cryothermia. However, despite the reported good results of various types of interventions in the hands of highly qualified teams, catheter ablation cannot be applied to all patients with AF or to all types of AF. Furthermore, catheter ablation of AF requires sophisticated electrophysiologic laboratories equipped with expensive imaging techniques and a well-trained staff that cannot be available in sufficient number to cover the growing epidemic of AF with acceptable efficacy and safety even in rich countries. Therefore, there is still a need for pharmacological therapy aimed at the prevention of AF recurrences for the majority of AF patients. So far, attempts to provide the physician with efficient antiarrhythmic agents having a good safety profile have not been successful. However, recent research resulted in promising new approaches including prevention of AF using converting enzyme inhibitors or angiotensin 2 receptor blockers, new antiarrhythmic agents with multichannel effects such as dronedarone and tedisamil and atrial specific agents that theoretically should have no ventricular proarrhythmic effect as they target specific atrial channels such as I(KAch) and I(Kur) which are absent at the ventricular level. Other possible mechanisms of AF that represent potential targets, such as modification of stretch-activated ion channels, intervention of altered connexin expression and altered gap-junctional conductance, are currently investigated.

Dofetilide: a new class III antiarrhythmic agent

Dofetilide is a relatively new class III antiarrhythmic agent that selectively blocks the rapid component of the cardiac ion channel delayed rectifier current. This results in an increase in the action potential duration and effective refractory period of the myocyte, thereby terminating reentrant tachyarrhythmias and preventing their re-induction. Oral dofetilide is effective in the conversion of atrial fibrillation and flutter to sinus rhythm and in the maintenance of sinus rhythm after conversion. It is generally well tolerated but like other antiarrhythmic agents in its class, torsades de pointes may be induced as a consequence of therapy. This risk is minimized by dosage adjustment according to creatinine clearance and QT(c) interval, by selecting patients without known risk factors for torsades and by initiating treatment in a monitored hospital setting for the first 3 days. Unlike other antiarrhythmic agents, oral dofetilide did not increase mortality in patients with a recent myocardial infarction or congestive heart failure, hence its importance as an alternative medication for the pharmacological conversion of atrial fibrillation and flutter, and maintenance of sinus rhythm after conversion in patients at high risk of sudden death.

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.