Are Transthoracic Echocardiographic Parameters Associated With Atrial Fibrillation Recurrence or Stroke?: Results From the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Study

OBJECTIVES: The purpose of this study was to evaluate the associations of transthoracic echocardiographic parameters with recurrent atrial fibrillation (AF) and/or stroke. BACKGROUND: The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study, an evaluation of elderly patients with AF at risk for stroke, provided an opportunity to evaluate the implications of echocardiographic parameters in patients with AF. METHODS: Transthoracic echocardiographic measures of mitral regurgitation (MR), left atrial (LA) diameter, and left ventricular (LV) function were evaluated in the AFFIRM rate- and rhythm-control patients who had sinus rhythm resume and had these data available. Risk for recurrent AF or stroke was evaluated with respect to transthoracic echocardiographic measures. RESULTS: Of 2,474 patients studied, 457 had > or =2(+)/4(+) MR, and 726 had a LA diameter >4.5 cm. The LV ejection fraction was abnormal in 543 patients. The cumulative probabilities of at least one AF recurrence/stroke were 46%/1% after 1 year and 84%/5% by the end of the trial (> 5 years), respectively. Multivariate analysis showed that randomization to the rhythm-control arm (hazard ratio [HR] = 0.64; p < 0.0001) and a qualifying episode of AF being the first known episode (HR = 0.70; p < 0.0001) were associated with decreased risk. Duration of qualifying AF episode >48 h (HR = 1.55; p < 0.0001) and LA diameter (p = 0.008) were associated with an increased risk of recurrent AF. Recurrent AF was more likely with larger LA diameters (HR = 1.21, 1.16, and 1.32 for mild, moderate, and severe enlargement, respectively). No transthoracic echocardiographic measures were associated with risk of stroke. CONCLUSIONS: In the AFFIRM study, large transthoracic echocardiographic LA diameters were associated with recurrent AF, but no measured echocardiographic parameter was associated with stroke.     

Is There Still a Role for Digoxin in the Management of Atrial Fibrillation?

Purpose of Review

A number of recent observational analyses have assessed clinical outcomes associated with digoxin use in patients with atrial fibrillation. In this review, we review these data and provide suggestions on the contemporary use of digoxin in patients with atrial fibrillation as supported by the recent evidence.

Recent Findings

Observational data from clinical trials and registries have provided variable results on the safety and efficacy of chronic digoxin use in patients with atrial fibrillation. In general, results have been consistent with an associated increase in adverse clinical outcomes with digoxin use in atrial fibrillation patients without heart failure. In atrial fibrillation patients with heart failure, while the weight of evidence suggested an associated risk with digoxin therapy, the results are inconsistent.

Summary

In patients with atrial fibrillation without heart failure, digoxin should generally be avoided. In atrial fibrillation patients with heart failure, digoxin should generally be reserved for patients that do not achieve adequate rate control or are not tolerant of other rate control therapies.

     

Can Ablation Prevent the Excess Mortality of Atrial Fibrillation?

The relative merits of rate and rhythm control in the treatment of patients with atrial fibrillation have been compared in several major clinical trials, none of which demonstrated a significant difference in all-cause mortality. Yet, there is clear evidence that restoration and maintenance of sinus rhythm is associated with beneficial reverse atrial remodeling. These apparently contradictory findings may reflect the combination of serious adverse effects coupled with limited efficacy of currently available antiarrhythmic drugs, counterbalancing their beneficial effect in restoring sinus rhythm. Catheter ablation offers an alternative means of restoring sinus rhythm in patients with atrial fibrillation, and several clinical trials have indicated its superior outcomes and improved benefit/risk profile. Ongoing trials will soon determine its overall impact on survival.     

Antiarrhythmic Surgery to Cure Atrial Fibrillation—Subgroups and Postoperative Management

Antiarrhythmic surgical procedures to cure atrial fibrillation (AF) are widely used in cardiac surgery. Whereas the Cox maze procedure remains the highly effective gold-standard a variety of different antiarrhythmic procedures aim at reducing the extent and duration of the procedure. Antiarrhythmic procedures are especially effective in patients undergoing mitral valve surgery. In 110 patients with permanent AF undergoing various surgical procedures sinus rhythm was re-established in 75%. Subgroup analyses revealed no significant differences in rhythm or survival after antiarrhythmic intraoperative ablation indicating the usefulness and feasibility of this procedure in patients with a wide range of characteristics. Because conversion usually occurs spontaneously within the first 6 months and antiarrhythmic medication does not increase the incidence of conversion it seems reasonable to wait for spontaneous occurrence of sinus rhythm after antiarrhythmic intraoperative ablation. In patients with permanent AF undergoing open heart surgery additional antiarrhythmic procedures have been shown to be safe and effective.     

Assessment and Impact of Cardiac Fibrosis on Atrial Fibrillation

Real-time magnetic resonance imaging (MRI) combines the advantages of excellent soft-tissue characterization in a true 3D anatomical and functional model with the possibility of lesion and gap visualization without the need of any radiation. Therefore, real-time MRI presents a particularly attractive imaging technology to guide electrophysiology studies and catheter ablation procedures. This article aims to provide an overview on current routine clinical application of MRI in the setting of interventional electrophysiology. Furthermore, development of real-time MRI guided electrophysiology studies and first experiences with MRI guided catheter ablation procedures are depicted. In this context advantages, challenges and limitations of real-time MRI guided catheter ablation as well as future perspectives are discussed.     

Results of Atrial Fibrillation Ablation in Patients With or Without a History of Atrial Flutter

INTRODUCTION There are two kinds of atrial flutter will meet during AF ablation. Left atrial flutter (LAFL) is a known complication of catheter-based therapies of atrial fibrillation (AF). Linear catheter ablation may lead to instances of“gap”within the…     

Is It Time to Move on from Two-Dimensional Transesophageal to Three-Dimensional Transthoracic Echocardiography for Assessment of Left Atrial Appendage? Review of Existing Literature

Left atrial appendage (LAA) has unique anatomical and physiological properties, which make it a common site for thrombus formation in many cardiovascular and systemic diseases. Assessment of LAA for thrombus thus becomes important in many clinical situations and two-dimensional transesophageal echocardiography (2D TEE), which allows excellent quality images of LAA because of its close proximity to esophagus is routinely used for this purpose. However, it is a semiinvasive procedure, requires more time and involves some degree of patient discomfort. With some training and experience, two-dimensional transthoracic echocardiography (2D TTE) can visualize LAA in most patients with good acoustic windows. A disadvantage of both 2D TTE and 2D TEE is that they provide only a thin slice or section of cardiac structures at any given time limiting their utility in comprehensively assessing the LAA for thrombus. On the other hand, live/real time three-dimensional (3D) TTE overcomes this limitation of both 2D TTE and 2D TEE because of its ability to encompass whole of the LAA in three-dimensions in the acquired data set, which can then be cropped and sectioned systematically at any desired angulation to more definitively look for clot. 3D TTE is also useful in differentiating a clot from pectinate muscles in the LAA, which can mimic a thrombus resulting in patient mismanagement. In addition, 3D TTE is helpful in sectioning a clot for lysis, which has implications in clot resolution. We reviewed the existing literature comparing the relative advantages and disadvantages of 3D TTE versus 2D TEE and found that in patients with good acoustic windows 3D TTE had similar efficacy for detecting LAA thrombus. (Echocardiography 2012;29:112-116)     

The Relation of Atrial Fibrillation and Inflammation Do Inflammation Imply the Pathogenesis of Atrial Fibrillation？

Atrial fibrillation （AF）, the most commonly encountered arrhythmia in clinical practice, is associated with a 2-fold increase in total cardiovascular mortality, as well as the potential for substantial morbidity, including stroke, congestive heart failure, and cardiomyopathy. Its incidence and prevalence are increasing, and it represents a growing clinical and economic burden. Owing to relative inefficacy and side effects of current pharmacological and non-pharmacological therapy for AF, it remains a great challenge to improve primary and secondary AF prevention strategies to reduce this potentially enormous health burden.     

What Is the Role of Left Atrial Appendage Closure in the Rhythm Control of Atrial Fibrillation?

Interventional catheter ablation approaches to the rhythm control of atrial fibrillation (AF) have advanced significantly in the past decade. The foundation of the catheter ablation in AF is electrical isolation of the pulmonary veins (PVI). However, PVI only in more advanced stages of AF (persistent AF) has only modest to poor success rates prompting a search for alternative and adjunctive procedures to improve the outcomes of ablation in persistent AF. The left atrial appendage (LAA) is well understood to be a primary source of emboli in AF but less well known be a trigger or driver for AF. Therefore, LAA exclusion is an attractive target to potentially improve AF ablation outcomes in more advanced stages of AF and possibly as an alternative to chronic oral anticoagulation in the prevention of stroke and systemic embolism in AF. However, the precise role of LAA closure in the interventional approach to AF is still to be elucidated with ongoing clinical investigations.     

Is Bachmann's Bundle the Only Right Site for Single-Site Pacing to Prevent Atrial Fibrillation? Results of a Multicenter Randomized Trial

The site of atrial pacing influences atrial activation patterns. It is believed that disparities in atrial activation and repolarization are contributors to the development and recurrence of atrial arrhythmias. We hypothesized that pacing from Bachmann's Bundle would improve clinical outcomes in patients with paroxysmal atrial fibrillation compared to right atrial appendage pacing. Pacing from Bachmann's Bundle results in a significant reduction in P wave duration and improvement in biatrial activation symmetry compared to right atrial appendage pacing. Compared to right atrial appendage pacing, Bachmann's bundle pacing improves sinus rhythm (75% vs. 47% at two years, p < 0.01) in patients with a history of paroxysmal atrial fibrillation. Recent studies have confirmed the benefits of Bachmann's Bundle pacing on atrial activation and rhythm regulation. Thus, Bachman's Bundle should be considered the preferred site for atrial pacing in patients with a history of paroxysmal atrial fibrillation.