2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Updating the 2006 Guideline)

Efficacy and safety profile of dronedarone in clinical practice. Results of the Magdeburg Dronedarone Registry (MADRE study)

BACKGROUND

Dronedarone is a new antiarrhythmic agent that has only recently been approved for the therapy of atrial fibrillation (AF). Results regarding a broader spectrum of patients and experience accumulated in clinical practice are still very scarce. Therefore, we prospectively investigated the efficacy and tolerance of dronedarone in a real life setting.

METHODS AND RESULTS

The study included 191 patients (85 women) aged 63 ± 9.9 years with a history of paroxysmal or persistent AF. Follow-up time was 14.3 ± 4.9 months. In patients with persistent AF, sinus rhythm was restored using electrical cardioversion prior to dronedarone administration. Each patient underwent standard ECG on a daily basis during the first 4 days of treatment, and on days 7, 30 and 90, resp. After that, the patients had a follow-up visit every three months. Creatinine, creatine kinase, and hepatic enzymes were closely monitored. Clinical history was meticulously taken at multiple follow-up visits. Dronedarone maintained sinus rhythm in 33.5% (95% CI: 27%-40%), and AF recurrence rate was high: 66.5% (95% CI: 60%-73%). Adverse effects occurred in 31.9% (95% CI: 27%-38%) of the patients and necessitated permanent discontinuation of dronedarone in 22% (95% CI: 17%-27%).

CONCLUSIONS

The results suggest that dronedarone may not be superior to available antiarrhythmic agents and caution against its use as a first line therapy in AF.

An evidence-based review of apixaban and its potential in the prevention of stroke in patients with atrial fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia, especially in the elderly population. It is associated with cardioembolic complications, particularly strokes, resulting in severe functional deficit or death. AF patients are first stratified into low, intermediate, and high risk for thromboembolic events using the CHADS(2) and CHA(2)DS(2)-VASc score systems. Depending on their risks, patients are treated with either therapeutic anticoagulation with warfarin or acetylsalicylic acid for stroke prevention. Although warfarin is the recommended therapy, it is underutilized clinically due to concern for narrow therapeutic window, drug-to-drug and drug-to-food interactions, and hemorrhagic complications. Newer anticoagulant agents such as dabigatran (a direct thrombin inhibitor) and rivaroxaban (a direct factor Xa inhibitor) have already been approved by US Food and Drug Administration for stroke prevention in patients with nonvalvular atrial fibrillation. Apixaban is the newest oral direct factor Xa inhibitor and it has been extensively studied in the AVERROES and ARISTOTLE trials. Apixaban demonstrated reduced incidence of primary outcome of stroke and bleeding events when compared with warfarin. Apixaban is currently being reviewed by the Food and Drug Administration as a stroke prophylactic agent. In addition, there are several other indirect factor Xa inhibitors and vitamin K antagonists under study presently. Results from these studies will provide us with information about possible alternatives to warfarin.

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.

Frequency and causes of stroke during or after transcatheter aortic valve implantation

Transcatheter aortic valve implantation (TAVI) is invariably associated with the risk of clinically manifest transient or irreversible neurologic impairment. We sought to investigate the incidence and causes of clinically manifest stroke during TAVI. A total of 214 consecutive patients underwent TAVI with the Medtronic-CoreValve System from November 2005 to September 2011 at our institution. Stroke was defined according to the Valve Academic Research Consortium recommendations. Its cause was established by analyzing the point of onset of symptoms, correlating the symptoms with the computed tomography-detected defects in the brain, and analyzing the presence of potential coexisting causes of stroke, in addition to a multivariate analysis to determine the independent predictors. Stroke occurred in 19 patients (9%) and was major in 10 (5%), minor in 3 (1%), and transient (transient ischemic attack) in 6 (3%). The onset of symptoms was early (≤24 hours) in 8 patients (42%) and delayed (>24 hours) in 11 (58%). Brain computed tomography showed a cortical infarct in 8 patients (42%), a lacunar infarct in 5 (26%), hemorrhage in 1 (5%), and no abnormalities in 5 (26%). Independent determinants of stroke were new-onset atrial fibrillation after TAVI (odds ratio 4.4, 95% confidence interval 1.2 to 15.6), and baseline aortic regurgitation grade III or greater (odds ratio 3.2, 95% confidence interval 1.1 to 9.3). In conclusion, the incidence of stroke was 9%, of which >1/2 occurred >24 hours after the procedure. New-onset atrial fibrillation was associated with a 4.4-fold increased risk of stroke. In conclusion, these findings indicate that improvements in postoperative care after TAVI are equally, if not more, important for the reduction of periprocedural stroke than preventive measures during the procedure.

Patient-Centered Management of Atrial Fibrillation: Applying Evidence-Based Care to the Individual Patient

Atrial fibrillation is the most common arrhythmia encountered in clinical practice, and it is one of the most common cardiac conditions requiring hospitalization of a patient. Several national organizations have developed guidelines for the management of atrial fibrillation. These guidelines were updated in 2011 to incorporate new advances in antiarrhythmic drug therapy and anticoagulant therapy, as well as progress in the field of catheter ablation. Many decisions about patient care involve consideration of issues related to lifestyle and quality of life rather than survival. These decisions also involve addressing the key topics of heart rate control, heart rhythm control, and stroke prevention. During the past decade, important advances in the management of atrial fibrillation have created a number of treatment options that have roughly equivalent therapeutic efficacies when they are used for several common clinical situations encountered in clinical practice. The range of available treatments for patients with atrial fibrillation provides an important opportunity for the physician to deliver patient-centered care, which uses patient values to determine the best course of treatment.

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.

Addressing the management of atrial fibrillation - a systematic review of the role of dronedarone

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia. It occurs in 1%-2% of the general population and its prevalence increases with age. Dronedarone, a noniodinated benzofuran similar to amiodarone, was developed as an antiarrhythmic agent for patients with atrial fibrillation. The aim of our systematic review was to critically evaluate randomized controlled trials that compared treatment with dronedarone versus placebo or amiodarone in patients with atrial fibrillation.

METHODS

Electronic databases (MEDLINE, Embase, and Central) were searched up to November 2011 with no language restrictions. We included randomized controlled trials in which dronedarone was compared to placebo or other drugs in patients with AF. Internal and external validity was assessed.

RESULTS

We identified seven papers corresponding to eight randomized controlled trials. The DAFNE, EURIDIS/ADONIS, and ATHENA trials demonstrated a reduction of AF recurrence with dronedarone as compared to placebo in patients with nonpermanent AF. The DIONYSOS study showed that dronedarone is less effective for the prevention of recurrent AF but improved tolerability as compared to amiodarone. Considering patients with permanent AF, the ERATO trial showed that dronedarone had rate-control effects while the PALLAS study was stopped early since stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes were significantly more frequent in subjects treated with dronedarone as compared to placebo. The ANDROMEDA trial included patients with recent hospitalization for heart failure and was terminated early because of excess of deaths in the dronedarone group.

CONCLUSION

Like most antiarrhythmic drugs, dronedarone reduces the recurrence of AF in patients with paroxysmal or persistent AF as compared to placebo. However, relapse rates in the first year of therapy are high. Moreover, dronedarone showed to be less effective than amiodarone. Finally, dronedarone should be avoided in patients with permanent AF and a high risk for cardiovascular events or severe congestive heart failure.

Thrombo-embolism and antithrombotic therapy for heart failure in sinus rhythm. A joint consensus document from the ESC Heart Failure Association and the ESC Working Group on Thrombosis

Chronic heart failure (HF) with either reduced or preserved ejection fraction is common and remains an extremely serious disorder with a high mortality and morbidity. Many complications related to HF can be related to thrombosis. Epidemiological and pathophysiological data also link HF to an increased risk of thrombosis, leading to the clinical consequences of sudden death, stroke, systemic thrombo-embolism, and/or venous thrombo-embolism. This consensus document of the Heart Failure Association (EHFA) of the European Society of Cardiology (ESC) and the ESC Working Group on Thrombosis reviews the published evidence and summarizes 'best practice', and puts forward consensus statements that may help to define evidence gaps and assist management decisions in everyday clinical practice. In HF patients with atrial fibrillation, oral anticoagulation is recommended, and the CHA(2)DS(2)-VASc and HAS-BLED scores should be used to determine the likely risk-benefit ratio (thrombo-embolism prevention vs. risk of bleeding) of oral anticoagulation. In HF patients with reduced left ventricular ejection fraction who are in sinus rhythm there is no evidence of an overall benefit of vitamin K antagonists (e.g. warfarin) on mortality, with risk of major bleeding. Despite the potential for a reduction in ischaemic stroke, there is currently no compelling reason to use warfarin routinely for these patients. Risk factors associated with increased risk of thrombo-embolic events should be identified and decisions regarding use of anticoagulation individualized. Patient values and preferences are important determinants when balancing the risk of thrombo-embolism against bleeding risk. New oral anticoagulants that offer a different risk-benefit profile compared with warfarin may appear as an attractive therapeutic option, but this would need to be confirmed in clinical trials.

Improving long-term ACS management: is there a role for the new antiplatelets?

Acute coronary syndrome (ACS) is a major health burden, resulting in increased hospital admissions and significant morbidity and mortality. Platelet activation, which leads to thrombin generation, is highly implicated in ACS, and antiplatelet agents represent the current standard of care. Established antiplatelet agents include acetylsalicylic acid (ASA), thienopyridines (clopidogrel, ticlopidine), and glycoprotein IIb/IIIa inhibitors. Recently, antiplatelet therapy for ACS has evolved to include more potent inhibitors (e.g., prasugrel, cangrelor, and ticagrelor). During the acute phase of an acute coronary event, both anticoagulation and dual antiplatelet therapy with aspirin and a thienopyridine are guideline recommended as first-line treatment. While anticoagulation is usually limited to the acute in-patient phase, dual antiplatelet therapy is recommended for 12 months. Despite the efficacy of antiplatelet agents in ACS, in many patients the residual risk of death from cardiac events, myocardial infarction, stroke, and refractory ischemia remains high. Dual therapy (i.e., ASA or clopidogrel plus a vitamin K antagonist [VKA]), and triple therapy (two antiplatelets plus a VKA) are associated with increases in bleeding complications. New oral anticoagulants that offer a novel mechanism of action may, when added to the current standard of care, provide a more comprehensive response to thrombin generation. In this review, we examine the pathology of ACS, investigate antiplatelet therapies and describe emerging anticoagulants that may be of benefit when used as combination therapy with antiplatelet agents for secondary prevention in ACS patients.

Spontaneous normal sinus rhythm conversion using integrative medicine in atrial fibrillation

The relationship between acute life stress and the development of atrial fibrillation (AF) has been noted in the literature. However, the use of integrative medicine (IM) in restoring cardiac rhythm has not been adequately studied. This case report describes how an IM approach was used in a patient with atrial fibrillation and acute pain. Spontaneous cardioversion to normal sinus rhythm occurred during the IM session, in addition to marked decreases in self-reported pain, anxiety, and nausea at the conclusion of IM treatment. These results provide initial support that for some cases of AF, IM therapies can help to reduce costs via avoidance of additional hospitalization, electrocardioversion, and general anesthesia.

Barriers to translating EU and US CVD guidelines into practice in China

With the increasing globalization of clinical research and evidence, clinical-practice guidelines (CPGs) developed by the European Union (EU) and the USA are also becoming increasingly international. However, these CPGs can encounter barriers to their practical application. In this Perspectives article, we analyze the main obstacles to the application of EU and US CPGs for cardiovascular diseases from the unique perspective of China, and highlight some potential problems in the globalization of CPGs. Currently, China and other countries with limited independent evidence for CPG development must localize or adapt the CPGs developed by the EU, the USA, or international medical organizations, with systematic consideration of cost-effectiveness and alternative strategies on the basis of the available evidence from the native populations. At the same time, comprehensive capabilities to collect and review clinical evidence to produce population-specific CPGs should be developed.

Dronedarone-current status in management of atrial fibrillation

Atrial fibrillation (AF) is the most common of the serious cardiac rhythm disturbances and is responsible for substantial morbidity and mortality. Available drug therapy for AF has modest efficacy and is associated with the risk of life-threatening pro-arrhythmic complications. Dronedarone is a newer therapeutic agent with a structural resemblance to amiodarone and a better side effect profile. It is a multichannel blocker with antiadrenergic properties and has been evaluated in both rate and rhythm control strategies in the management of AF. In this review, we discuss the current role of dronedarone in the contemporary management of AF.

Outcome of Patients Discharged after their First Detected Episode of Atrial Fibrillation

Atrial fibrillation (AF) is the most frequent supraventricular arrhythmia with an approximative prevalence of 1 % in the general population and above 6 % in the elderly. After a first AF diagnosis, the hospitalization rate is markedly increased. Management of a first AF episode is different depending on the clinical status of patients. Practical guidelines developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society are available for the management of these patients. A four-step decisional scheme must be followed in the management of a first recent AF episode: need for a short- and long-term anticoagulation, define a rythmologic strategy (rhythm or rate control), select the weapon (drug, device or ablation) and reconsider the strategy if needed. After a first uncomplicated paroxysmal AF episode, guidelines recommend that prescription of antiarrhythmics must be avoided and anticoagulation is optional. After a first persistent AF episode, guidelines recommend to either respect or reduce the arrhythmia. Prescription of antiarrhythmics and anticoagulation is also optional depending on the patient?s condition. In case of the AF reduction decision, anticoagulation must be tailored preliminary to this reduction. AF recurrence rate varies depending on the patient?s condition, and the risk of stroke assessed by the CHA₂DS₂-VASc score might be similarly considered for both paroxysmal and persistent AF.

Robotically controlled ablation for atrial fibrillation: the first real-world experience in Africa with the Hansen robotic system

Background

We report the first single-centre experience in Africa with the Sensei X robotic navigation system in an unselected subset of patients with atrial fibrillation (AF).

Methods

Data were recorded prospectively of all consecutive patients who underwent robotically assisted catheter ablation therapy using the Sensei X robotic navigation system at the Christiaan Barnard Memorial Hospital, Cape Town, South Africa, from July 2009 to July 2010. Outcomes were defined at one and nine months.

Results

A total of 95 patients were included: 63% had only AF and 37% had AF plus atrial flutter. AF was of the persistent type in 81% of patients. The mean procedure, fluoroscopy and ablation times were 220.6 ± 89.6 min, 31.0 ± 20.4 min, and 61.3 ± 28.1 min, respectively. Both fluoroscopy and procedure times were significantly longer for the first 19 patients compared with the remaining 76 patients (43.5 ± 22.7 vs 27.8 ± 18.5 min and 274.7 ± 90.2 vs 207.1 ± 84.7 min, respectively, p = 0.002). The procedural endpoint of the study was successfully achieved in all patients. After one attempt, 27% were discharged from hospital off anti-arrhythmic drugs (AADs). At a median of nine months’ follow up, 74% were AF-free off AADs, and 11% were AF-free on AADs, yielding a total freedom from AF of 84% without any redo procedures. Freedom from relapse after 1.12 procedures was 88%.

Conclusion

The Sensei X™ robotic navigation system offers a safe and effective approach for the treatment of AF. There was a learning curve with regard to fluoroscopy and procedure time, after which point reduction in radiation exposure and operator strain, as well as improvement in procedure throughputs were even more pronounced.

Highlights from the IV International Symposium of Thrombosis and Anticoagulation (ISTA), October 20-21, 2011, Salvador, Bahia, Brazil

To discuss and share knowledge about advances in the care of patients with thrombotic disorders, the Fourth International Symposium of Thrombosis and Anticoagulation was held in Salvador, Bahia, Brazil, from October 20-21, 2011. This scientific program was developed by clinicians for clinicians and was promoted by three major clinical research institutes: the Brazilian Clinical Research Institute, the Duke Clinical Research Institute of the Duke University School of Medicine, and Hospital do Coração Research Institute. Comprising 2 days of academic presentations and open discussion, the symposium had as its primary goal to educate, motivate, and inspire internists, cardiologists, hematologists, and other physicians by convening national and international visionaries, thought-leaders, and dedicated clinician-scientists. This paper summarizes the symposium proceedings.

Lone atrial fibrillation: where are we now?

There is a growing pandemic of atrial fibrillation (AF), affecting nearly 2% of the general adult population. Atrial fibrillation is commonly associated with structural heart disease, and AF itself causes a sequence of complex processes of electrical, contractile, and structural remodeling of the atrial myocardium, which facilitate further AF progression. Nonetheless, AF may also affect individuals aged ≤ 65 years who have no evidence of associated cardiopulmonary or other disease, including hypertension; this is otherwise referred to as "lone" AF and is considered to have a generally favorable prognosis. The true prevalence of lone AF is unknown. Growing insights into the diversity of numerous mechanisms involved in the pathogenesis of AF, including acute atrial stretch, structural and electrophysiological alterations, systemic inflammation, oxidative stress, autonomic imbalance, genetic predisposition, and many others, and increasing recognition of novel risk factors for AF, including obesity, metabolic syndrome, subclinical atherosclerosis, sleep apnea, alcohol consumption, and endurance sports, suggest that apparently lone AF might not be so "lone" in many patients, which could have important prognostic and therapeutic implications. In this article, we summarize the current knowledge of epidemiology, etiopathogenesis, and pathophysiology of so-called lone AF and discuss the issues of long-term prognosis and management of patients who have an apparently lone AF.

Role of inflammation in early atrial fibrillation recurrence

AIMS

Outcome of rhythm control in atrial fibrillation (AF) is still poor due to various mechanisms involved in the initiation and perpetuation of AF. Differences in timing of AF recurrence may depend on different types of mechanisms. The aim of this study was to assess the mechanisms involved in early AF recurrence in patients with short-lasting AF.

METHODS AND RESULTS

Patients with short-lasting persistent AF undergoing rhythm control (n= 100) were included. Markers of mechanisms involved in the initiation and perpetuation of AF were assessed, including clinical factors, echocardiographic parameters, and biomarkers. Primary endpoint was early AF recurrence (recurrence <1 month). Secondary endpoint was progression to permanent AF. Median total AF history was short: 4.2 months. Early AF recurrences occurred in 30 patients (30%) after a median of 6 (inter-quartile range 2-14) days. Baseline log(2) interleukin (IL)-6 [adjusted hazard ratio (HR) 1.3, 95% confidence interval (CI) 1.0-1.7, P= 0.02] and present or previous smoking (adjusted HR 3.6, 95% CI 1.2-10.9, P= 0.03) were independently associated with early AF recurrence, suggesting that inflammation played an important role in early recurrences. Atrial fibrillation became permanent in 29 patients (29%). Baseline transforming growth factor-β1, left ventricular ejection fraction, and early AF recurrence were independently associated with progression to permanent AF.

CONCLUSION

In patients with short-lasting AF, early AF recurrence seemed to be associated with inflammation as represented by IL-6. Treatment aimed against inflammation may therefore prevent early AF recurrences, which can improve rhythm control outcome.

Stroke prevention in elderly patients with atrial fibrillation: challenges for anticoagulation

Elderly patients with atrial fibrillation (AF), who constitute almost half of all AF patients, are at increased risk of stroke. Anticoagulant therapies, especially vitamin K antagonists (VKA), reduce the risk of stroke in all patients including the elderly but are frequently under-used in older patients. Failure to initiate VKA in elderly AF patients is related to a number of factors, including the limitations of current therapies and the increased risk for major haemorrhage associated with advanced age and anticoagulation therapy. Of particular concern is the risk of intracranial haemorrhages (ICH), which is associated with high rates of mortality and morbidity. Novel oral anticoagulant agents that are easier to use and might offer similar or better levels of stroke prevention with a similar or reduced risk of bleeding should increase the use of antithrombotic therapy in the management of elderly AF patients. Amongst these new agents, the recently approved direct thrombin inhibitor dabigatran provides effective stroke prevention with a significant reduction of ICH, and enables clinicians to tailor the dose according to age and haemorrhagic risk.

Identifying a high stroke risk subgroup in individuals with heart failure

BACKGROUND

Heart failure (HF) is associated with an overall stroke rate that is too low to justify anticoagulation in all patients. This study was conducted to determine if vascular risk factors can identify a subgroup of individuals with heart failure with a stroke rate high enough to warrant anticoagulation.

METHODS

The REGARDS study is a population-based cohort of US adults aged ≥45 years. Participants are contacted every 6 months by telephone for self- or proxy-reported stroke and medical records are retrieved and adjudicated by physicians. Participants were characterized into 3 groups: HF without atrial fibrillation (AF), AF with or without HF, and neither HF nor AF. Cardiovascular risk factors at baseline were compared between participants with and without incident stroke in HF and AF. Stroke incidence was assessed in risk factor subgroups in HF participants.

RESULTS

Of the 30,239 participants, those with missing/anomalous data were excluded. Of the remaining 28,832, 1360 (5%) had HF without AF, 2528 (9%) had AF, and 24,944 (86%) had neither. Previous stroke/transient ischemic attack (TIA; P = .0004), diabetes mellitus (DM; P = .03), and higher systolic blood pressure (P = .046) were associated with increased stroke risk in participants with HF without AF. In participants with HF without AF, stroke incidence was highest in those with previous stroke/TIA and DM (2.4 [1.1, 4.0] per 100 person-years).

CONCLUSIONS

The combination of previous stroke/TIA and DM increases the incidence of stroke in participants with HF without AF. No analyzed subgroup had a stroke rate high enough to make it likely that the benefits of warfarin would outweigh the risks.

Hypertension and atrial fibrillation: epidemiology, pathophysiology and therapeutic implications

Hypertension is one of the most important risk factors associated with atrial fibrillation (AF) and increased the risk of cardiovascular events in patients with AF. However, the pathophysiological link between hypertension and AF is unclear. Nevertheless, this can be explained by the hemodynamic changes of the left atrium secondary to long standing hypertension, resulting in elevated left atrium pressure and subsequently left atrial enlargement. Moreover, the activation of renin-angiotensin-aldosterone system (RAAS) activation in patients with hypertension induces left atrial fibrosis and conduction block in the left atrium, resulting in the development of AF. Accordingly, recent studies have shown that effective blockage of RAAS by angiotensin converting enzyme inhibitors or angiotensin receptor antagonist may be effective in both primary and secondary prevention of AF in patients with hypertension, although with controversies. In addition, optimal antithrombotic therapy, blood pressure control as well as rate control for AF are key to the management of patients with AF.

Radiofrequency catheter ablation and antiarrhythmic drug therapy: a prospective, randomized, 4-year follow-up trial: the APAF study

BACKGROUND

Information on comparative outcome between radiofrequency catheter ablation (RFA) and antiarrhythmic drugs (AADs) >1 year after randomization is important for clinical decision-making.

METHODS AND RESULTS

A total of 198 patients (age, 56 ± 10 years) with paroxysmal atrial fibrillation were randomly assigned to RFA (99 patients) or to AADs (99 patients). We evaluated efficacy of RFA or AADs in a comparable 48-month follow-up period according to intention-to-treat analysis. Cardiac rhythm was assessed with daily transtelephonic transmissions. Quality of life was also analyzed. At 4 years, among the 99 patients first assigned to RFA, the procedure was repeated because of recurrent atrial fibrillation/atrial tachycardia in 27 patients (27.3%). Among the 99 patients randomly assigned to AADs, 87 (87.9%) crossed over to undergo RFA and 4 years after random assignment only 12 (12.1%) were in sinus rhythm with AAD alone without ablation. Despite the high level of crossovers, at 4 years the intention-to-treat analysis showed that 72.7% of patients in the ablation arm and 56.5% of those initially randomly assigned to AADs were free of recurrent atrial fibrillation/atrial tachycardia (P=0.017). During the follow-up, 19.2% of AAD patients progressed to persistent atrial fibrillation before switching to RFA. RFA significantly improved quality of life (P<0.001), whereas before crossing over to RFA, patients receiving AADs showed poorer quality of life. Except for new left atrial tachycardia, there were no serious complications caused by RFA.

CONCLUSIONS

With follow-up extended to 4 years after randomly assigned, ablation remains superior to antiarrhythmic drug in these patients with paroxysmal atrial fibrillation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00340314.

Pharmacologic strategies for the prevention of stroke in patients with atrial fibrillation

OPINION STATEMENT

Stroke is a dreaded complication of atrial fibrillation. In the past, preventive therapy included aspirin and oral anticoagulation. Selected patients who are not suitable for oral anticoagulation may benefit from the addition of clopidogrel with aspirin. This combination, when compared with aspirin, offers a reduced risk of stroke at a cost of more major bleeding. We use this therapy in patients with atrial fibrillation who have unstable coronary syndromes or in patients who receive coronary artery stents who are not good candidates for "triple therapy" with aspirin, clopidogrel, and warfarin. The duration of therapy is tempered by many variables. In the case of coronary stents, we ask the interventionalist to consider a bare metal stent to shorten the duration of need for clopidogrel plus aspirin. After several months of combination therapy, we stop this therapy and begin warfarin therapy. Dabigatran is commercially available in the United States. In patients who have difficult to control International Normalized Ratio (INR) values or who do not wish to have regular coagulation monitoring, dabigatran offers a huge advantage. The benefit seems less if the INR is consistently within range. We are impressed with the superior reduction in stroke and systemic embolism with 150 mg of dabigatran twice daily compared to warfarin and also its low risk of intracranial hemorrhage. The results of clinical trials involving factor Xa agents are now being presented. How these agents fit into the marketplace remains to be seen but they will offer clinicians additional therapy for stroke prevention in atrial fibrillation.

Role of emerging antithrombotic therapy in the prevention of cardioembolic complications in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is an independent risk factor of potentially catastrophic cardioembolic strokes. AF patients are categorized into high-, intermediate-, and low-risk for thromboembolic complications using the CHADS(2) or CHA(2)DS(2)-VASc scoring system. Oral anticoagulation using warfarin has been the standard therapy for stroke prevention in intermediate- to high-risk AF patients. However, warfarin use has been limited by several factors such as narrow therapeutic windows, drug-drug and drug-food interactions, and hemorrhagic complications. Rigorous research evaluated dual antiplatelet therapy of clopidogrel and aspirin (acetylsalicylic acid) as a potential alternative to warfarin in the ACTIVE W trial. Dual antiplatelet therapy of clopidogrel and aspirin was found to be inferior to warfarin in preventing stroke and systemic embolism with increased bleeding risk. Other extensive research has led to the development of new antithrombotic agents. Recently, dabigatran etexilate 150 mg twice daily, a direct thrombin inhibitor, was approved by the US FDA for stroke prevention in patients with non-valvular AF after it was found to be superior to warfarin in preventing thromboembolic events and associated with less bleeding in the RE-LY trial. It was also cost effective when compared with warfarin. Dabigatran can be considered in high-risk AF patients who are unable or unwilling to comply with the frequent laboratory and clinic visits that are required when receiving treatment with warfarin. Factor Xa inhibitors are another class of new anticoagulants that have been developed. Oral rivaroxaban was non-inferior to warfarin in thromboprophylaxis and with similar bleeding in the ROCKET-AF trial (HR 0.88; p = 0.117). Apixaban, another factor Xa inhibitor, was superior to aspirin in reducing stroke and systemic embolism in patients with AF in the AVERROES trial (HR 0.45; p < 0.001). The results of the ARISTOTLE trial, which is evaluating apixaban against warfarin in ∼18 000 patients with AF, are expected to be available later this year. Edoxaban, another oral factor Xa inhibitor, is currently being evaluated against warfarin in the ENGAGE AF-TIMI 48 trial in ∼20 000 patients with AF. With these new developments, there is a necessity for the clinical practitioner to become familiar with these new and upcoming therapies and guidelines. This review provides an overview of the available data regarding the clinical usefulness of these agents.

Battle of oral anticoagulants in the field of atrial fibrillation scrutinized from a clinical practice (the real world) perspective

Warfarin has a long history of benefit and has become the gold standard medication for the prevention of ischemic stroke in patients with atrial fibrillation. Nevertheless, it is far from perfect and there is no doubt that new drugs must be found to replace warfarin. The new oral anticoagulants that are on the market or awaiting approval or under research offer some benefits but not enough to replace warfarin until results of additional studies can show an adequate balance between effectiveness/safety and cost/benefit. There are several issues concerning the new oral anticoagulants. It is essential that the effect of any anticoagulant can be measured in plasma. But to date, there is no test to assess the effect or therapeutic range for the new oral anticoagulants. There is no antidote to neutralize the action of the new drugs in cases of bleeding or when acute surgical intervention is necessary. Dabigatran requires dose adjustment in patients with moderate renal impairment and is contraindicated in patients with severe renal failure. Rivaroxaban should be used with caution in patients with severe renal impairment. Apixaban excretion is also partly dependent on renal function, although the impact of renal insufficiency has not yet been determined. How anticoagulant bridging can be done before surgery has not yet been established. In conclusion, although thousands of patients have been treated in phase III studies, additional data are necessary before conclusions can be drawn on the potential for these new anticoagulant drugs to replace warfarin in patients with atrial fibrillation.

Clopidogrel hydrogen sulphate for atrial fibrillation

INTRODUCTION

Atrial fibrillation is a common cardiac rhythm abnormality with a considerable cardiovascular disease burden worldwide. It is an independent major risk factor for stroke. Stroke prevention with anticoagulation or antiplatelet agents has been an important area of clinical research. Warfarin is the most widely used antithrombotic therapy for stroke prophylaxis for last several years, and now dabigatran (150 mg b.i.d.) is more effective than warfarin in stroke prevention in individuals at increased of stroke. In addition, several studies have evaluated the efficacy of clopidogrel for stroke prophylaxis either alone or in combination with aspirin.

AREAS COVERED

This review summarizes the key findings of the trials looking at the efficacy of clopidogrel in stroke prevention. A literature search was performed using PubMed and Google Scholar. The trials that evaluated the efficacy of clopidogrel in preventing atherothrombotic events or stroke were also included.

EXPERT OPINION

Clopidogrel prevents more vascular events, including stroke, in patients with a recent myocardial infarction, stroke or peripheral vascular disease than aspirin. Combination of clopidogrel and aspirin provides a greater reduction of stroke than aspirin or clopidogrel monotherapy, but at an increased risk of bleeding. Dual antiplatelet therapy (clopidogrel and aspirin) is inferior to warfarin in primary stroke prevention for patient with atrial fibrillation and thus should be considered for stroke prophylaxis only in patients ineligible for warfarin. However, with the advent of newer agents, like direct thrombin inhibitors and Factor Xa inhibitors, the role of antiplatelet therapy for stroke prevention in atrial fibrillation remains unclear.

Presentation of atrial fibrillation and its management by cardiologists in the ambulatory and hospital setting: MOVE cross-sectional study

OBJECTIVE

The aim of the study was to collect comprehensive data on atrial fibrillation (AF) in ambulatory and hospital-based management in Germany.

METHODS

Consecutive patients with ECG-confirmed AF in the previous 12 months were documented in a non-interventional study in 638 physician offices (78.0%) or hospitals (12.7%).

RESULTS

Of the 3354 patients (mean age 68.9 ± 10.1 years; CHADS(2) score 1.9 ± 1.3), a total of 1136 (33.9%) had paroxysmal, 899 (26.8%) persistent, 1295 (38.6%) permanent and 24 (0.7%) unspecified AF. In the 12 months prior to documentation, pharmacological conversion was attempted in 18.2%, electric cardioversion in 17.5%, the combination of both in 31.2%, and catheter ablation of AF in 5.5%. Only 41.4% of patients met the definition of stable disease (having neither AF related intervention nor change in antiarrhythmic therapy in the previous 12 months). As treatment strategy, physicians stated rate control in 64%, rhythm control in 8%, and both in 19% (not reported: 8%). Patients received antiarrhythmic drugs of class IA in 1.3%, IC in 13.8%, II in 78.1%, III in 17.9%, IV in 9.7% and digitalis in 26.7%. Drugs for thromboembolic prevention (oral anticoagulants and/or antithrombotics) were administered in 81.5%. Hospitalisations for AF or associated diseases in the previous 12 months were reported in 34.2%. Possible limitations include the open, observational design, selection of physicians with particular interest in the field and selection of patients (i.e. underrepresentation of critically ill individuals).

CONCLUSIONS

While treatment rates with regards to the prevention of thromboembolic events were among the highest reported to date, the low proportion of stable patients and in particular, the high hospitalisation rate hint at difficulties in the management of patients with AF in clinical practice.