Is the Atrial Neural Plexis a Therapeutic Target in Atrial Fibrillation?

Circumferential pulmonary vein isolation is the mainstay of atrial fibrillation (AF) ablation, but alternative approaches and techniques have been developed to improve the outcomes. One of these additional ablation targets are ganglionated plexi of the intrinsic cardiac autonomic system that contain a variety of sympathetic and parasympathetic neurons that communicate with the extrinsic cardiac autonomic nervous system. The ganglionated plexi of the heart do not serve as a simple relay station but could modulate the autonomic interaction between the extrinsic and intrinsic cardiac autonomic system. Intrinsic cardiac autonomic nerve activity is an invariable trigger of paroxysmal atrial tachyarrhythmia, including atrial fibrillation. Although multiple studies have shown that ganglionated plexi play an important role in initiating atrial fibrillation, there is no consensus on a standardized protocol for selecting target sites and determining how ganglionated plexi ablation can best be accomplished. Recent clinical trials have demonstrated the feasibility and efficacy of ganglionated plexi ablation in addition to pulmonary vein isolation, but novel technologies and strategies are necessary to improve the current ablation techniques in managing patients with atrial fibrillation. This review focuses on the relationship between atrial ganglionated plexi and atrial fibrillation and the potential benefits and limitations of ganglionated plexi ablation in the management of atrial fibrillation.     

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…     

Gene Expression of Atrial Calcium-Handling Proteins in Patients with Rheumatic Heart Disease and Atrial Fibrillation

Objectives To investigate the gene expression of calcium - handling proteins in patients with rheumatic heart disease (RHD) and atrial fibrillation (AF) . Methods A total of 50 patients with rheumatic mitral valve disease were included. According to cardiac rhythm and duration of episode of AF, patients were divided into four groups: sinus rhythm group, paroxysmal AF group, persistent AF for less than 6 months group and persistent AF for more than 6 months group. Atrial tissue was obtained from the right atrial appendage, the right atrial free wall and the left atrial appendage respectively during open heart surgery. Total RNA was isolated and reversly transcribed into cDNA. In a semi - quantitative polymerase chain reaction the cDNA of interest and of glyceralde-hyde3 - phosphate dehydrogenase (GAPDH) were amplified and separated by ethidium bromide - stained gel electrophoresis. Multiple liner regress was used for correlation between the mRNA amount and age, sex, right atrial diameter (RAd) and left a     

Effect of mmPs/TIMPs on Atrial Structural Remodeling in A Chronic Canine Atrial Fibrillation Model

Objective Atrial fibrillation (AF) is commonly associatedwith atrial dilation and fibrosis, but the mechanism underlying these abnormalities remains unclear. The purpose of this study is to investigate the effect of matrix metalloproteinase-9 (mmP-9)and tissue in hibitor metalloproteinase -1 (TIMP-1) on extracellular matrix of atrium.     

Elevated Incidence of Atrial Fibrillation and Stroke in Patients With Atrial Flutter—A Population-Based Study

Background

The risk of stroke from atrial flutter and its relationship with progression to atrial fibrillation (AF) is unclear. This study describes the incidence of AF and stroke in patients with atrial flutter, and whether atrial flutter ablation attenuates the incidence of AF and stroke.

Digoxin and Mortality in Patients With Atrial Fibrillation

Background

Digoxin is widely used in patients with atrial fibrillation (AF).

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.     

Atrial Fibrillation in Heart Failure: An Innocent Bystander?

Heart failure (HF) and atrial fibrillation (AF) frequently coexist and each complicates the course of the other. The purpose of this review is to analyse the prognostic impact of AF in patients with HF and assess whether there is an advantage in targeting therapies towards the maintenance of sinus rhythm (SR) in this cohort of patients. The presence of AF in patients with HF has been reported to be independently associated with an increase in mortality in many studies and this increased risk is observed in those with both preserved and impaired LV systolic function. The optimal strategy for targeting AF in patients with HF is unclear but recent randomised controlled studies indicate no significant prognostic advantage associated with a rhythm control strategy as compared to a rate control strategy. A number of small studies have investigated the role of both cardiac resynchronization therapy (CRT) and AF catheter ablation for the maintenance of / conversion to SR in patients with HF with initial promising results although larger randomised controlled studies will need to be performed to define the role of these modalities in the treatment of this cohort and whether preliminary benefits observed in these studies translate to improvements in longer term prognosis. Finally, there has been a focus on modifying the arrythmogenic atrial substrate and neurohormonal milieu by pharmacological means in order to prevent AF although it remains to be seen whether this approach proves to be efficacious with improvements in clinically relevant outcomes.     

Arrhythmia Recurrence After Atrial Fibrillation Ablation: Can Magnetic Resonance Imaging Identify Gaps in Atrial Ablation Lines?

After pulmonary vein isolation for the treatment of atrial fibrillation, clinical arrhythmia recurrence is often a result of vein reconnection. By selectively visualizing scarred tissue, delayed enhancement magnetic resonance imaging may provide for a noninvasive means to identify gaps in radiofrequency ablation lines. This report correlates three-dimensional magnetic resonance imaging with invasive electroanatomical mapping in a patient with recurrent atrial arrhythmia after multiple unsuccessful ablations for atrial fibrillation.     

Do the Left Atrial Substrate Properties Correlate with the Left Atrial Mechanical Function? A Novel Insight from the Electromechanical Study in Patients with Atrial Fibrillation

Background: The atrial substrate is the determinant of occurrence and maintenance of atrial fibrillation (AF), which can induce remodeling of atrial function and structure. This study investigated the relationship between the left atrial (LA) substrate properties and LA mechanical function.
Methods: Forty-four consecutive patients (50.3 ± 10.7 years old, 33 men) who presented with sinus rhythm during echocardiographic study before receiving catheter ablation for AF were enrolled. The LA diameter, LA volume, ratio of early and late transmitral filling flow velocities (E/A), LA appendage flow velocity, and transmitral velocity-time integral (VTI) were measured by the echocardiography. The LA empty fraction (LAEF), which was obtained via dividing the difference between maximal and minimal LA volume by maximal LA volume, was calculated as a parameter of the global LA contractile function. The LA global contact voltage mapping (NavX system) was performed before pulmonary vein isolation.
Results: Mean LA voltage and LA low voltage zone index (LVZ index, area with voltage < 0.5 mV, divided by total LA surface area) showed significant correlation with LA diameter and volume, but only the LA LVZ index showed significant correlation with A-wave velocity, transmitral A-wave VTI, and LAEF (r =–0.340, –0.411, –0.426; P = 0.024, 0.006, 0.005, respectively). We divided the LA LVZ index into three groups (< 10%, 10–20%, > 20%). The LAEF got worse and the transmitral A-wave VTI percentage (divided by transmitral VTI) decreased as LA LVZ index increased.
Conclusions: The LA substrate properties showed close correlation with LA size, but only the LA LVZ index correlated with the LA mechanical function.     

Atrial fibrillation in a tertiary care institute – A prospective study

ObjectiveAtrial fibrillation is the commonest sustained arrhythmia. In western countries the common causes of atrial fibrillation are hypertensive heart disease, dilated cardiomyopathy, and coronary heart disease. Rheumatic heart disease being still common in India, we studied its contribution to atrial fibrillation.Material and methods137 consecutive patients of atrial fibrillation coming to our hospital were subjected to echocardiography to determine the cause.ResultsOut of 137 patients with atrial fibrillation, 76 were female (55.47%) and 61 were male (44.43%). Mean age was 51.24 ± 15.36 years. Commonest cause of AF was rheumatic heart disease found in 84 (61.31%) patients. Next common causes were hypertensive heart disease in 14 (10.2%) patients and chronic obstructive pulmonary disease (COPD) in 14 (10.2%) patients. Mean left atrial size was 47.8 ± 12.25 mm.ConclusionIn our study of patients coming from a rural back ground of North India, more than 60% patients of AF are due to RHD. Hypertensive heart disease and COPD are the next common causes.