Rate control vs rhythm control in patients with nonvalvular persistent atrial fibrillation: the results of the Polish How to Treat Chronic Atrial Fibrillation (HOT CAFE) Study

Role of left atrial speckle tracking echocardiography in predicting persistent atrial fibrillation electrical cardioversion success and sinus rhythm maintenance at 6 months

PURPOSE

We assessed the value of left atrium speckle tracking imaging (STI) indices, and clinical and other echocardiographic parameters in persistent atrial fibrillation (AF) patients to predict the efficacy of electrical cardioversion (EC) and sinus rhythm (SR) maintenance at 6 months.

MATERIAL/METHODS

Eighty persistent AF patients planned to receive EC, underwent echocardiography including STI. After 24h, patients with successful EC were examined to predict SR maintenance. After 6 months patients with no AF recurrence in electrocardiogram (ECG) underwent 7-day ECG to exclude silent AF. Every AF>1 min was a recurrence.

RESULTS

SR restored in 61 patients, 19 unsuccessful. Prior use of statins (68.8% vs. 42.1%, p=0.03) was the only factor, determined later by univariate analysis to be a significant EC success predictor (OR=1.09, CL ± 95% 1.001-1.019, p<0.03). Both groups received similar antiarrhythmics and had similar echocardiographic parameters. After 6 months, SR was maintained in 19 patients (31.1%, Group I); AF recurrences were registered in 42 patients (68.8%, Group II). In Group I, only the mitral valve deceleration time (MVDT) 224.18 ± 88.13 vs. 181.6 ± 60.6 in Group II, p=0.04) and the dispersion of time to peak longitudinal strain (dTPLS) (86.0 ± 68.3 vs. 151.8 ± 89.6, p=0.03) differed significantly. The univariate analysis revealed dTPLS as a significant predictor of SR maintenance.

CONCLUSION

High EC efficacy and frequent AF recurrences were observed. The dispersion of time to the maximal longitudinal strain (LS) of left atrial segments facilitated prediction of SR maintenance. The value of 7-day ECG monitoring for detection of arrhythmia after 6 months was limited.

AF Detected on Implanted Cardiac Implantable Electronic Devices: Is There a Threshold for Thromboembolic Risk?

OPINION STATEMENT

Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with elevated thromboembolism risk caused by multiple pathophysiologies, including a hypercoagulable state, structural heart changes, left atrial appendage stasis, inflammation, and endothelial dysfunction. With the exception of lone AF, most other categories of AF, whether paroxysmal or persistent, have been shown to share a high thromboembolism risk. Risk stratification schemes such as CHADS2 and CHA2DS2-VASc scores help to identify the level at which anticoagulation may mitigate thromboembolism risk. AF may be episodic and asymptomatic; therefore, AF diagnosis that depends entirely on office electrocardiogram (ECG) may be easily missed. With the increasing use of pacemakers, implantable cardioverter defibrillators (ICDs), and insertable loop recorders (ILRs) for diagnosis and treatment of arrhythmias, AF has been incidentally detected with increasing frequency. However, the sensitivity and specificity for detection of AF, especially brief episodes, vary from one type of device to another, and rhythm confirmation should be considered. Several recent studies have examined device-detected AF and have tried to follow associated clinical outcomes. In this paper, we review studies that have addressed device-detected AF and associated thromboembolism risk to try to identify the burden of AF that is associated with an elevated risk of thromboembolism and may therefore warrant anticoagulation therapy.

Atrial fibrillation and congestive heart failure

Heart failure (HF) and atrial fibrillation (AF) commonly coexist and adversely affect mortality when found together. AF begets HF and HF begets AF. Rhythm restoration with antiarrhythmic drugs failed to show a mortality benefit but can be effective in improving symptoms. Nonpharmacologic treatment of AF may be of value in the HF population.

Addressing the controversy of rate-versus-rhythm control in atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia and significantly increases patient risk of stroke, cardiomyopathy, and mortality. Rate versus rhythm control as the "best" treatment strategy remains an issue of considerable, ongoing debate. A multitude of clinical trials have compared the 2 strategies and have not shown any benefit of one approach over the other. However, the trials were conducted in specific subgroups of patients and demonstrated low success rates with antiarrhythmic drug (AAD) therapy and a high incidence of adverse AAD effects. Sub-analyses of the trials have confirmed that successful rhythm control with sinus rhythm restoration is associated with a significant reduction in patient mortality. More recently, radiofrequency ablation (RFA) has emerged as a relatively effective procedure for maintaining sinus rhythm compared with use of AADs. Prospective randomized studies have shown good treatment results after the use of RFA, with acceptable risk. Given the limitation of pharmacologic rate versus rhythm control studies, and the promise of RFA, rhythm control should again be reconsidered as the "best" approach for managing many subgroups of patients with atrial fibrillation.

Comparative effectiveness of antiarrhythmic drugs on cardiovascular hospitalization and mortality in atrial fibrillation

AIM

To assess, through a systematic review, evidence for the effects of antiarrhythmic drugs (AADs) on cardiovascular (CV) hospitalization and mortality.

MATERIALS & METHODS

English language articles were identified using MEDLINE, EMBASE and the Cochrane Clinical Trial Registry and were screened for study applicability and methodological quality.

RESULTS

Out of 3526 identified studies, 38 were selected for analysis (19 evaluated individual AADs, 13 compared rate- versus rhythm-control strategies, and 6 evaluated multiple AADs but did not report outcomes for individual agents). None of the studies examining individual AADs employed the CV hospitalization end point used in ATHENA (the reference trial). There were no head-to-head comparisons of individual AADs on CV hospitalization. Most high-quality studies used multidrug rate- versus rhythm-control strategies.

CONCLUSION

Assessment of the comparative effectiveness of individual AADs on CV hospitalization and mortality end points is not possible with the current evidence.

Atrial fibrillation in the elderly

Atrial fibrillation (AF) is the most common arrhythmia in older adults with a prevalence of 9 % in adults aged 80 years or older. AF patients have a five times greater risk of developing stroke than the general population. Using anticoagulants for stroke prevention in the elderly becomes a challenge because both stroke and bleeding complications increase with age. CHA₂DS₂-VASc and HAS-BLED scores are currently used as stroke and bleeding risk evaluations. When the HAS-BLED score is 3 or higher, caution and efforts to correct reversible risk factors are advised. Regardless of the HAS-BLED score, warfarin or novel oral anticoagulants are a IIa recommendation for CHA₂DS₂-VASc of 1, except for a score of 1 for females, and a IA recommendation for the score of 2 or higher. Aspirin is no longer recommended for AF thromboprophylaxis. In an elderly patient, lenient rate control is preferred over rhythm control owing to fewer adverse drugs effects and hospitalizations. When rhythm control is needed, dronedarone is a new antiarrhythmic drug that can be considered in patients who have paroxysmal AF and no history of heart failure. Although less efficacious than amiodarone, dronedarone has a fewer thyroid, neurologic, dermatologic, and ocular side effects than amiodarone.

Practical Issues to Prevent Stroke Associated with Non-valvular Atrial Fibrillation

Stroke associated with non-valvular atrial fibrillation (NVAF) is one of the most important subtypes of ischemic stroke, and its importance is becoming even more apparent in an aging population. To assess the risk of stroke associated with NVAF, the CHADS2 and CHA2DS2-VASc scores are mainly used. Such scores can be used to predict the recurrence and prognosis of ischemic stroke. In addition, new oral anticoagulants (NOACs) and devices are being evaluated in the prevention of stroke associated with NVAF in addition to treatment with the conventional oral anticoagulant, warfarin. Since clinical experience with NOACs is not globally sufficient, a cautious approach is needed.

Surgical treatment of atrial fibrillation in the heart failure population

Surgery to correct a structural heart valve problem can restore sinus rhythm in approximately one-fifth of patients with atrial fibrillation (AF), and the addition of a maze procedure will increase this proportion. Evidence shows that the maze procedure may restore atrial function in some patients and may have beneficial effects on functional symptoms and prognosis. The role of the maze procedure as an isolated treatment for lone AF in the context of heart failure with no structurally correctable cause is unknown. Future progress will determine the appropriate indications for treatment and the risks and benefits of any intervention.

Improving outcomes in patients with atrial fibrillation: rationale and design of the Early treatment of Atrial fibrillation for Stroke prevention Trial

BACKGROUND

Even on optimal therapy including anticoagulation and rate control, major cardiovascular complications (stroke, cardiovascular death, and acute heart failure) are common in patients with atrial fibrillation (AF). Conceptually, maintenance of sinus rhythm could prevent adverse outcomes related to AF. Rhythm control therapy has been only moderately effective in published trials, and its potential benefit was offset by side effects of repeated interventions.

RATIONALE

Rhythm control therapy applied early after the first diagnosis of AF could preserve atrial structure and function and maintain sinus rhythm more effectively than the current practice of delayed rhythm control (when symptoms persist after otherwise effective rate control). Furthermore, catheter ablation and new antiarrhythmic drugs have enhanced the potential effectiveness and safety of rhythm control therapy. The EAST will test whether an early, modern rhythm control therapy can reduce cardiovascular complications in AF.

DESIGN

The EAST (Early treatment of Atrial fibrillation for Stroke prevention Trial) will randomize approximately 3,000 patients with recent onset AF at risk for stroke (CHA₂DS₂VASc score ≥2) to either guideline-mandated usual care or to usual care plus early rhythm control therapy in a prospective, randomized, open, blinded outcome assessment trial. All patients will be followed up until the end of the trial for the composite primary outcome of cardiovascular death, stroke, worsening of heart failure, and myocardial infarction. Nights spent in hospital will be counted as a coprimary outcome. Usual care will consist of anticoagulation, therapy of underlying heart disease, and rate control as an initial approach. Early rhythm control therapy will consist of usual care plus rhythm control therapy by antiarrhythmic drugs, catheter ablation, and a patient-operated electrocardiographic device to monitor the ongoing rhythm. Key secondary outcomes include cognitive function and quality of life.

CONCLUSION

EAST will determine whether rhythm control therapy, when applied early after the initial diagnosis of AF, can prevent cardiovascular complications associated with AF.

Ventricular rate control of atrial fibrillation in heart failure

In the last few years, there has been a major shift in the treatment of atrial fibrillation (AF) in the setting of hear failure (HF), from rhythm to ventricular rate control in most patients with both conditions. In this article, the authors focus on ventricular rate control and discuss the indications; the optimal ventricular rate-control target, including detailed results of the Rate Control Efficacy in Permanent Atrial Fibrillation: a Comparison Between Lenient versus Strict Rate Control II (RACE II) study; and the pharmacologic and nonpharmacologic options to control the ventricular rate during AF in the setting of HF.

Antiarrhythmic drugs in atrial fibrillation: do they have a future?

Atrial fibrillation (AF) is a common arrhythmia associated with significant morbidity and mortality. There has been much debate about the relative merits of rate vs rhythm control strategies, and studies to date have failed to show advantage with a rhythm-control strategy using antiarrhythmic drugs (AADs). This is likely because of the inadequacies of our current AADs and the limitations of study designs. However, there is evidence that AADs improve symptoms and quality of life (QOL). Until trials are performed with more appropriate patient selection, and end points and better AADs and strategies for their use, rhythm control should not be abandoned and may continue to be beneficial in selected patients.

Benefit-risk assessment of dronedarone in the treatment of atrial fibrillation

Rhythm control in atrial fibrillation (AF) can be achieved using pharmacological therapy. Amiodarone is the most efficacious anti-arrhythmic agent; however, its use is limited due to an unfavourable safety profile, including pro-arrhythmia, thyroid, liver, skin and pulmonary complications. Dronedarone, which is structurally similar to amiodarone, was developed to try and achieve a favourable balance of efficacy and risk. Dronedarone has been evaluated in several large clinical trials, which have shown reduced mortality and hospitalization rates in patients with non-permanent AF. In patients with permanent AF and/or heart failure, dronedarone has been shown to cause increased mortality and morbidity and should not be used in these groups. Compared with amiodarone, dronedarone has fewer toxic effects (thyroid, skin, pulmonary) and, although less efficacious, may be used as first-line therapy for maintenance of sinus rhythm in patients with non-permanent AF. Clinicians must be vigilant in monitoring their patients to ensure they do not develop permanent AF or heart failure.

Cost-Effectiveness of Atrial Fibrillation Ablation

Atrial fibrillation (AF) is a frequently encountered rhythm disorder, characterized by high recurrence rate, frequent hospitalizations, reduced quality-of-life and increased the risk of mortality, heart failure and stroke. Along with these clinical complications this type of arrhythmia is the major driver of health-related expenditures. Radiofrequency catheter ablation (RFA) of atrial fibrillation has been shown to improve freedom from arrhythmia survival, reduce re-hospitalization rate and provide better quality-of-life as compared with rate control and rhythm control with antiarrhythmic therapy. Efficacy of AF ablation in terms of outcomes and costs has an evolving importance. In this review, we aimed to highlight current knowledge on AF ablation clinical outcomes based on results of randomized clinical trials and community-based studies, and overview how this improvement in clinical end-points affects costs for arrhythmia care and cost-effectiveness of AF ablation.

Atrial Fibrillation and Heart Failure: A Review of the Intersection of Two Cardiac Epidemics

Atrial fibrillation and heart failure are closely linked cardiac conditions that are both increasing in prevalence due to shared risk factors and common disease mechanisms. The presence of both disease entities portends an increase in morbidity and mortality. There are significant similarities in the treatment strategies of these conditions, and the adequate management of one disease may prevent the development of the other. To this date, a rhythm control strategy, even in the heart failure population, has not been proven to be superior to a rate control strategy. This may in large be due to study design coupled with deleterious effects of antiarrhythmic agents. There have been considerable advances over the past decade in catheter and device based management of atrial fibrillation and studies aimed to examine their long-term effect in patients with heart failure are underway.

Anti-Arrhythmic Agents in the Treatment of Atrial Fibrillation

Although atrial fibrillation (AF) is the most common sustained arrhythmia seen during daily cardiovascular physician practice, its management remained a challenge for cardiology physician as there was no single anti-arrhythmic agents proved to be effective in converting atrial fibrillation and kept its effectiveness in maintaining sinus rhythm over long term. Moreover all the anti-arrhythmic agents that are used in treatment of AF were potentially pro-arrhythmic especially in patients with coronary artery disease and structurally abnormal heart. Some of these drugs also have serious non cardiac side effects that limit its long term use in the management of atrial fibrillation. Several new and investigational anti-arrhythmic agents are emerging but data supporting their effectiveness and safety are still limited. In this systematic review we examine the efficacy and safety of these medications supported by the major published randomized trials, meta-analyses and review articles and conclude with a summary of guidelines recommendations.

Genetic mechanisms of atrial fibrillation: impact on response to treatment

Atrial fibrillation (AF) is the most-common sustained arrhythmia observed in clinical practice, but response to therapy is highly variable between patients. Current drug therapies to suppress AF are incompletely and unpredictably effective and carry substantial risk of proarrhythmia and noncardiac toxicities. The limited success of therapy for AF is partially the result of heterogeneity of the underlying substrate, interindividual differences in disease mechanisms, and our inability to predict response to therapies in individual patients. In this Review, we discuss the evidence that variability in response to drug therapy is also conditioned by the underlying genetic substrate for AF. Increased susceptibility to AF is mediated through diverse genetic mechanisms, including modulation of the atrial action-potential duration, conduction slowing, and impaired cell-to-cell communication, as well as novel mechanisms, such as regulation of signalling proteins important in the pathogenesis of AF. However, the translation of genetic data to the care of the patients with AF has been limited because of poor understanding of the underlying mechanisms associated with common AF-susceptibility loci, a dearth of prospective, adequately powered studies, and the challenges associated with determining efficacy of antiarrhythmic drugs. What is apparent, however, is the need for appropriately designed, genotype-directed clinical trials.

Comparing Antiarrhythmic Drugs and Catheter Ablation for Treatment of Atrial Fibrillation

In the past years, catheter ablation has evolved into an effective treatment option for symptomatic, drug-resistant atrial fibrillation (AF) and it has recently been implemented as a primary treatment strategy for patients with paroxysmal AF. Although a significant number of studies have evaluated the potential benefits of catheter ablation compared with anti-arrhythmic drug (AAD)-therapy, to date, there are only a small number of randomised controlled trials in the literature, and several issues remain unsolved. The aim of this review is to analyze the current literature regarding this important issue and further discuss the question, whether catheter ablation may be more beneficial when compared to AAD therapy.

Atrial fibrillation and heart failure in the elderly

Atrial fibrillation (AF) is a common clinical problem in elderly patients and especially in those with heart failure (HF). It is a major risk factor for serious cardiovascular events, such as stroke, HF and premature death. Both the prevalence and incidence of AF increase with age and its prevalence in the United States are estimated at more than 2.2 million, with nearly 75% of patients aged >65 years. Aging-related atrial remodeling with fibrosis, dilation and mitochondrial DNA mutations predispose elderly patients to AF. Current management options for AF, including rate control and anticoagulation therapy, can be successfully applied to the elderly population. New antiarrhythmic and anticoagulation medications such as dronedarone and dabigatran, respectively, can impact the approach to therapy in the elderly. Non-pharmacological options such as catheter-based ablation have also gained prominence and have been incorporated into the guidelines for management of AF. However, more trials in the elderly and very elderly segments are needed to clarify the safety and long-term efficacy of the new treatment options.

Current Evidence and Recommendations for Rate Control in Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice, which is associated with substantial risk of stroke and thromboembolism. As an arrhythmia that is particularly common in the elderly, it is an important contributor towards morbidity and mortality. Ventricular rate control has been a preferred and therapeutically convenient treatment strategy for the management of AF. Recent research in the field of rhythm control has led to the advent of newer antiarrhythmic drugs and catheter ablation techniques as newer therapeutic options. Currently available antiarrhythmic drugs still remain limited by their suboptimal efficacy and significant adverse effects. Catheter ablation as a newer modality to achieve sinus rhythm (SR) continues to evolve, but data on long-term outcomes on its efficacy and mortality outcomes are not yet available. Despite these current developments, rate control continues to be the front-line treatment strategy, especially in older and minimally symptomatic patients who might not tolerate the antiarrhythmic drug treatment. This review article discusses the current evidence and recommendations for ventricular rate control in the management of AF. We also highlight the considerations for rhythm control strategy in the management of patients of AF.

Management strategies in atrial fibrillation in patients with heart failure

Atrial fibrillation (AF) and heart failure (HF) frequently occur together, and their coexistence is associated with a poor prognosis. AF and HF share risk factors, but their relationship involves complex hemodynamic, neurohormonal, inflammatory, ultrastructural, and electrophysiologic processes that extend beyond epidemiological associations. The shared mechanisms underlying AF and HF have important implications for the treatment of AF in patients with HF. This article focuses on reviewing contemporary data as it pertains to AF management in patients with HF and provides insight into investigational therapies currently under development.

Cardiac ion channels and mechanisms for protection against atrial fibrillation

Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a different ion channel composition in the atria and ventricles. The present text will review the aetiology of arrhythmias with focus on AF and include a description of cardiac ion channels. Channels that constitute potentially atria-selective targets will be described in details. Specific focus is addressed to the recent discovery that Ca(2+)-activated small conductance K(+) channels (SK channels) are important for the repolarisation of atrial action potentials. Finally, an overview of current pharmacological treatment of AF is included.

Atrial fibrillation and stroke: the evolving role of rhythm control

OPINION STATEMENT

Atrial fibrillation (AF) remains a major risk factor for stroke. Unfortunately, clinical trials have failed to demonstrate that a strategy of rhythm control--therapy to maintain normal sinus rhythm (NSR)--reduces stroke risk. The apparent lack of benefit of rhythm control likely reflects the difficulty in maintaining NSR using currently available therapies. However, there are signals from several trials that the presence of NSR is indeed beneficial and associated with better outcomes related to stroke and mortality. Most electrophysiologists feel that as rhythm control strategies continue to improve, the crucial link between rhythm control and stroke reduction will finally be demonstrated. Therefore, AF specialists tend to be aggressive in their attempts to maintain NSR, especially in patients who have symptomatic AF. A step-wise approach from antiarrhythmic drugs to catheter ablation to cardiac surgery is generally used. In select patients, catheter ablation or cardiac surgery may supersede antiarrhythmic drugs. The choice depends on the type of AF, concurrent heart disease, drug toxicity profiles, procedural risks, and patient preferences. Regardless of strategy, given the limited effectiveness of currently available rhythm control therapies, oral anticoagulation is still recommended for stroke prophylaxis in AF patients with other stroke risk factors. Major challenges in atrial fibrillation management include selecting patients most likely to benefit from rhythm control, choosing specific antiarrhythmic drugs or procedures to achieve rhythm control, long-term monitoring to gauge the efficacy of rhythm control, and determining which (if any) patients may safely discontinue anticoagulation if long-term NSR is achieved.

MK-0448, a Specific Kv1.5 Inhibitor

Background—

We evaluated the viability of I Kur as a target for maintenance of sinus rhythm in patients with a history of atrial fibrillation through the testing of MK-0448, a novel I Kur inhibitor.

Methods and Results—

In vitro MK-0448 studies demonstrated strong inhibition of I Kur with minimal off-target activity. In vivo MK-0448 studies in normal anesthetized dogs demonstrated significant prolongation of the atrial refractory period compared with vehicle controls without affecting the ventricular refractory period. In studies of a conscious dog heart failure model, sustained atrial fibrillation was terminated with bolus intravenous MK-0448 doses of 0.03 and 0.1 mg/kg. These data led to a 2-part first-in-human study: Part I evaluated safety and pharmacokinetics, and part II was an invasive electrophysiological study in healthy subjects. MK-0448 was well-tolerated with mild adverse experiences, most commonly irritation at the injection site. During the electrophysiological study, ascending doses of MK-0448 were administered, but no increases in atrial or ventricular refractoriness were detected, despite achieving plasma concentrations in excess of 2 μmol/L. Follow-up studies in normal anesthetized dogs designed to assess the influence of autonomic tone demonstrated that prolongation of atrial refractoriness with MK-0448 was markedly attenuated in the presence of vagal nerve simulation, suggesting that the effects of I Kur blockade on atrial repolarization may be negated by enhanced parasympathetic neural tone.

Conclusions—

The contribution of I Kur to human atrial electrophysiology is less prominent than in preclinical models and therefore is likely to be of limited therapeutic value for the prevention of atrial fibrillation.

Rhythm versus rate control therapy and subsequent stroke or transient ischemic attack in patients with atrial fibrillation

BACKGROUND

Stroke is a debilitating condition with an increased risk in patients with atrial fibrillation. Although data from clinical trials suggest that both rate and rhythm control are acceptable approaches with comparable rates of mortality in the short term, it is unclear whether stroke rates differ between patients who filled prescriptions for rhythm or rate control therapy.

METHODS AND RESULTS

We conducted a population-based observational study of Quebec patients ≥65 years with a diagnosis of atrial fibrillation during the period 1999 to 2007 with the use of linked administrative data from hospital discharge and prescription drug claims databases. We compared rates of stroke or transient ischemic attack (TIA) among patients using rhythm (class Ia, Ic, and III antiarrhythmics), versus rate control (β-blockers, calcium channel blockers, and digoxin) treatment strategies (either current or new users). The cohort consisted of 16 325 patients who filled a prescription for rhythm control therapy (with or without rate control therapy) and 41 193 patients who filled a prescription for rate control therapy, with a mean follow-up of 2.8 years (maximum 8.2 years). A lower proportion of patients on rhythm control therapy than on rate control therapy had a CHADS(2) (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and previous stroke or TIA) score of ≥2 (58.1% versus 67.0%, P<0.001). Treatment with any antithrombotic drug was comparable in the 2 groups (76.8% in rhythm control versus 77.8% in rate control group). Crude stroke/TIA incidence rate was lower in patients treated with rhythm control in comparison with rate control therapy (1.74 versus 2.49, per 100 person-years, P<0.001). This association was more marked in patients in the moderate- and high-risk groups for stroke according to the CHADS(2) risk score. In multivariable Cox regression analysis, rhythm control therapy was associated with a lower risk of stroke/TIA in comparison with rate control therapy (adjusted hazard ratio, 0.80; 95% confidence interval, 0.74, 0.87). The lower stroke/TIA rate was confirmed in a propensity score-matched cohort.

CONCLUSIONS

In comparison with rate control therapy, the use of rhythm control therapy was associated with lower rates of stroke/TIA among patients with atrial fibrillation, in particular, among those with moderate and high risk of stroke.

Rate or rhythm control for atrial fibrillation: update and controversies

Atrial fibrillation is associated with increased mortality and considerable morbidity, including stroke, heart failure, and diminished quality of life. Despite these adverse outcomes, rhythm control has not demonstrated benefit in clinical trials. Antiarrhythmic medications, including recently developed agents, have limited efficacy in achieving durable sinus rhythm and substantial toxicity. A rate-control strategy is therefore more attractive for minimally symptomatic patients, but younger and more symptomatic patients may benefit from restoration of sinus rhythm. Catheter ablation is more effective than medications in preventing arrhythmia recurrence, avoids adverse effects associated with antiarrhythmic drugs, and should be considered early in symptomatic patients when success is likely. However, more definitive data are needed from randomized trials assessing long-term outcomes after ablation, including stroke risk and mortality. Clinical decision tools help select the appropriate management for individual patients. Lenient rate management is easy to achieve and seems reasonably safe for certain patients, although the optimum rate varies with individual comorbidities. Because safer and more effective pharmacologic and interventional therapies are now available, an individualized approach to atrial fibrillation management is essential.

Atrial fibrillation and atrial flutter: medical management

Atrial fibrillation (AF) and atrial flutter (AFL) are common cardiac arrhythmias in older adults. Medical management focuses on rate and rhythm control of AF and AFL to promote symptomatic relief and avoid tachycardia-mediated cardiomyopathy. Pharmacologic treatment of AF and AFL is especially challenging in the elderly because of the presence of comorbidities that may affect drug kinetics, and polypharmacy, which may lead to drug interactions. The potential for complications from medications and procedures required to achieve and maintain sinus rhythm must be carefully balanced against the benefits of therapy. This article reviews medical management of AF and AFL specifically relating to rate and rhythm control. The controversy of rate versus rhythm control is also discussed.

Heart rate control in patients with chronic atrial fibrillation and heart failure

The goal of this study was to determine whether aggressive heart rate (HR) control in patients with both chronic atrial fibrillation (AF) and heart failure (HF) is associated with improved outcomes. HR control is one of the mainstays in management of patients with AF. However, rate control can be challenging in patients with HF. This study was designed as an interventional clinical trial, using patients with chronic AF and left ventricular systolic dysfunction with left ventricular ejection fraction ≤40% (n=20) as their own controls. Intervention consisted of increasing doses of metoprolol succinate to achieve target resting HR <70 beats per minute. Clinical data were collected at baseline and after intervention, with paired t test used to evaluate statistically significant change. After 3 months of intervention, average resting HR decreased from 94±14 beats per minute to 85±12 beats per minute. Average metoprolol succinate dose at the end of the study was 121 mg. None of the outcomes improved significantly after the intervention, including exercise tolerance (meters walked on 6-minute walk test 326±83 vs 330±86), quality of life (Minnesota Living With Heart Failure Questionnaire score of 42.5±19 vs 38±21), and brain natriuretic peptide (242±306 pg/mL vs 279±395 pg/mL). Aggressive HR control was difficult in this group of patients with chronic AF and HF due to patient intolerance of increasing doses of β-blockade, and not associated with improved outcomes. Further studies are needed to establish guidelines for target HR in patients with chronic AF who also have significant HF.

Real-life global survey evaluating patients with atrial fibrillation (REALISE-AF): results of an international observational registry

Despite being one of the most studied arrhythmias, there is paucity of information regarding atrial fibrillation (AF) control in the general population and the treatment strategies utilized by healthcare providers. REALISE-AF is an ongoing international registry investigating the management of AF and its control in nonhospitalized subjects. The registry has enrolled patients in 26 countries worldwide with the primary aim to determine the control of AF. This article presents a review of the initial results from the REALISE-AF registry and compares it to major practice-changing clinical trials conducted in the past. It also gives an overview of the current management strategies, recent updates in treatment and what further developments portend in the future.

Atrial fibrillation, stroke, and quality of life

Contemporary management of atrial fibrillation imposes many challenges, particularly in the setting of our aging population. In addition to well-recognized consequences, such as stroke and mortality, emerging evidence relates atrial fibrillation to elevated risk of dementia, posing further therapeutic challenges. As the incidence of atrial fibrillation rises with age, the balance of controlling stroke risk and limiting major hemorrhage on anticoagulation has become increasingly critical in elderly patients. Appreciation of more extensive risk factors has made it possible to identify patients at very low risk of thromboembolism and higher risk of bleeding. However, practice guidelines in the United States and abroad have occasionally divergent viewpoints regarding how to best manage patients in various risk strata. Options for stroke prevention have expanded with novel antithrombotics and promising mechanical alternatives to anticoagulation, which may be at least as effective in preventing stroke without increasing bleeding risk. Catheter ablation has demonstrated impressive success at preventing atrial fibrillation recurrence in selected patients, and has the potential to further improve outcomes. In addition, the role of antiplatelet medications in patients deemed unsuitable for anticoagulation has been better clarified, although novel agents require further study to assess their impact on thromboembolism. High-bleeding risks associated with the concomitant use of multiple antithrombotics remains a major obstacle in patients with indications for both antiplatelet and anticoagulant therapy.

[Therapy of atrial fibrillation in the critically ill]

Atrial fibrillation (AF) is the most common form of arrhythmia in the intensive care unit (ICU) and is associated with increased mortality. A total of five types of AF can be distinguished: initially diagnosed, paroxysmal, persistent, long-standing persistent and permanent AF. In addition to the initial treatment, antithrombotic therapy, rate and rhythm management can be used. The treatment of comorbidities is part of the patient management and for patients with increased risk of thromboembolic events anticoagulation is recommended. The simplest risk assessment scheme is the CHADS score. In the acute setting rate control is important. Direct current cardioversion is urgently recommended for patients with AF when hemodynamic instability is present even in patients with AF and pre-excitation in Wolff-Parkinson-White syndrome. Pharmacological cardioversion may be considered in patients with AF when hemodynamic stability is present. When choosing the antiarrhythmic agent for critically ill patients only amiodarone can be considered with some exceptions due to the specific contraindications.

Do the benefits of anti-arrhythmic drugs outweigh the associated risks? A tale of treatment goals in atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac rhythm disorder and places a substantial burden on the US healthcare system. Unfortunately, there is no consensus as to whether patients should be treated with a primary rate- or rhythm-control strategy. The use of anti-arrhythmic drugs in the treatment of AF is discussed in the broader context of AF disease-management strategies with a focus on rhythm control. Outside of rhythm/ECG, AF treatment targets and cardiovascular outcomes are highlighted.