Tuesday, July 15, 2008

Design of an Outpatient Atrial Fibrillation Center of Excellence: Current Experience with the Delivery of Pre-Procedure and Post Procedure Care

The population of patients with atrial fibrillation (AF) continues to expand and emerges to be the most common arrhythmia we deal with.Referrals to centers performing catheter based ablation procedures for AF also continue to grow as catheter ablation becomes an increasingly accepted therapeutic approach.

In this article we will describe the infrastructure we have developed to manage our atrial fibrillation ablation population at the Richard and Annette Bloch Heart Rhythm Center at the University of Kansas Hospital.Our goal is to provide a “nuts and bolts” overview from the allied health professional perspective.For concise reviews of AF management we recommend the ACC/AHA/EFC 2006 guidelines and the HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation

Atrial Fibrillation and Heart Failure

Atrial fibrillation is common in heart failure patients and is associated with increased mortality.Pharmacologic trials have not shown any survival benefit for a rhythm control over a rate control strategy.It has been suggested that sinus rhythm is associated with a survival benefit, but that the risks of anti-arrhythmic drug treatment and poor efficacy offset the beneficial effect.Catheter ablation for atrial fibrillation can establish sinus rhythm without the risks of anti-arrhythmic drug therapy.Data from randomized trials demonstrating a survival benefit for patients undergoing an ablation procedure for atrial fibrillation are still lacking.

Ablation of the AV junction and permanent pacing remain a treatment alternative in otherwise refractory cases.Placement of a biventricular system may prevent or reduce negative consequences of chronic right ventricular pacing.Current objectives and options for treatment of atrial fibrillation in heart failure patients are reviewed.

Catheter ablation for atrial fibrillation in patients with obesity

Obesity is a risk factor for atrial fibrillation (AF) and common comorbid conditions such as hypertension, sleep apnea, and structural heart disease. This study was designed to determine whether catheter ablation of AF can be performed safely and effectively in obese and overweight patients compared with patients with normal body weight.

Is Empirical Four Pulmonary Vein Isolation Necessary for Focally Triggered Paroxysmal Atrial Fibrillation?

In this study the authors compared two different ablation strategies for the treatment of paroxysmal atrial fibrillation (AF): selective isolation of the pulmonary vein triggering AF (SePVI) versus empirical isolation of all the four pulmonary veins (EmPVI).

Skin Burn at the Site of Indifferent Electrode after Radiofrequency Catheter Ablation of AV Node for Atrial Fibrillation.

Radiofrequency Ablation of AV node with permanent pacemaker has been used to achieve rate control in persistent symptomatic atrial fibrillation. Although RF Ablation is safe, complications may occur in up to 3% of the procedures. A rare complication of 2nd degree skin burn at indifferent electrode site has been described here. This report highlights the rare but possible complication in patients undergoing such a procedure and help in preventing by taking appropriate measures.

Are Atrial-Selective Drugs Superior to Currently Available Antiarrhythmic Drugs Used in the Treatment of Atrial Fibrillation?

Current pharmacologic strategies for the management of atrial fibrillation (AF) include use of

1) sodium channel blockers, which are contraindicated in patients with coronary artery or tructural heart disease because of their potent effect to slow conduction in the ventricles,

2) potassium channel blockers, which predispose to acquired long QT and Torsade de Pointes arrhythmias because of their potent effect to prolong ventricular repolarization, and

3) mixed ion channel blockers such as amiodarone, which are associated with multi-organ toxicity.Accordingly, recent studies have focused on agents that selectively affect the atria but not the ventricles.

Several atrial-selective approaches have been proposed for the management of AF, including inhibition of the atrial-specific ultrarapid delayed rectified potassium current (IKur), acetylcholine-regulated inward rectifying potassium current (IK-ACh), or connexin-40 (Cx40).

All three are largely exclusive to atria.Recent studies have proposed that an atrial-selective depression of sodium channel-dependent parameters with agents such as ranolazine may be an alternative approach capable of effectively suppressing AF without increasing susceptibility to ventricular arrhythmias.

Clinical evidence for Cx40 modulation or IK-ACh inhibition are lacking at this time. The available data suggest that atrial-selective approaches involving a combination of INa, IKur, IKr, and, erhaps, Ito block may be more effective in the management of AF than pure IKur or INa block. The anti-AF efficacy of the atrial-selective/predominant agents appears to be similar to that of conventionally used anti-AF agents,with the major difference being that the latter are associated with ventricular arrhythmogenesis and extracardiac toxicity.

Trigger Versus Substrate Ablation for Atrial Fibrillation.

Elimination of triggers has become the hallmark of catheter ablation of atrial fibrillation (AF). In particular, much attention has been paid to the elimination of triggering impulses from the pulmonary veins via pulmonary vein ablation procedures. While this approach has a proven track record for paroxysmal AF, the efficacy in non-paroxysmal AF has been less convincing. Thus, attention has been paid to elimination of the substrate responsible for AF perpetuation, including complex fractionated electrograms, dominant frequency sites, and autonomic ganglionated
plexi. None of these targets has yet become mainstream, but they are all under active investigation. As our knowledge of these targets increases and clinical studies are performed, a more refined approach to AF ablation will surely emerge.

Pre-Procedural Imaging to Direct Catheter Ablation of Atrial Fibrillation: Anatomy and Ablation Strategy.

Successful catheter ablation of atrial
fibrillation (AF) requires a detailed understanding of left atrial anatomy in
order to maximize the safety and efficacy of the procedure. Common and rare variants of left atrial and
pulmonary venous anatomy have been described which can affect the optimal
ablation strategy for each individual patient. These variants include the presence of a right or left middle pulmonary
vein, a left or right common pulmonary vein, a common inferior pulmonary vein,
a right top pulmonary vein, and other rare forms of anomalous pulmonary venous
drainage. There are also important
patient-specific differences in pulmonary venous ridges and left atrial roof
morphology. Pre-procedural CT or MR
imaging can define these anatomic variants in exquisite detail and be used with
image-integration strategies to direct the ablation procedure. In this review, we describe common and
uncommon variants that can be identified by pre-procedural imaging, and suggest
ablation strategies tailored to these anatomic variants.

Atrial Fibrillation Ablation In Obesity , Size Matters

Both obesity and atrial fibrillation (AF) have a significant negative impact on morbidity and mortality. In recent times, these conditions have become growing public health problems, being described separately as emerging epidemics. Obesity is increasingly recognized as a risk factor for developing AF, with the risk escalating with increasing body mass index (BMI). In addition, this association is greater for long-standing and permanent AF, suggesting a possible role for obesity in the maintenance of AF as well.


Review of "Long-term endurance sport practice increases the incidence of lone atrial fibrillation in men: a follow-up study"


The study is aimed to determine the incidence of lone atrial fibrillation in males according to sport practice levels and to identify possible clinical markers that increase the risk of lone atrial fibrillation (LAF) among marathon runners.

more ...

Review of "Antiarrhythmic Effect of Statin Therapy and Atrial Fibrillation : A Meta-Analysis of Randomized Controlled Trials"


The aim of this meta-analysis was to improve the evaluation of the possible antiarrhythmic effect of statins on atrial fibrillation (AF) incidence or recurrence.


Success of Radiofrequency Catheter Ablation of Atrial Fibrillation: Does Obesity Influence the Outcomes?

Background: Catheter ablation of atrial fibrillation (AF) is an increasingly popular therapeutic option for symptomatic patients who have failed multiple antiarrhythmic medications. Patients of higher body mass index often fail direct current cardioversion. The role of body mass index (BMI) on the success of AF ablation is not well understood.

Methods: We prospectively studied 893 patients who underwent AF ablation at the Cleveland Clinic Foundation between 1999 and 2003. Patients were divided into four classes based on their BMI: Class I (≤ 25); Class II (25.1-30); Class III (30.1-35) and Class IV (>35). They were compared for baseline demographic and clinical characteristics. Any recurrence of AF after 3 months of ablation was considered as failure. All classes were followed for at least 12 months and rates of failure were compared.

Results: Based on their BMI, 25% of patients were assigned to class I, 37% in class II, 21% in class III and 16% in class IV. Patients of higher classification (class III or IV) were more likely to be male (p<0.001), diabetic (p<0.001), smokers (p=0.002), with coronary artery disease (=0.018), echocardiographic evidence of left atrial enlargement (p=0.015) and longstanding AF (p=0.007). We found a significant correlation between long-term (one-year) AF recurrence after catheter ablation and BMI classification with recurrence rates of 5.2% in class I, 7.5% in class II, 14.1% in class III and 8.4% in class IV (p=0.01). The short-term recurrence rates of 12.7% in class I, 19.1% in class II, 23.0% in class III and 17.4% in class IV did not achieve statistical significance (p=0.05) .

Conclusion: Obesity is significantly associated with long-term AF recurrence after catheter ablation. Higher incidence of systemic inflammation, smoking & left atrial enlargement possibly contribute to higher failure rates in this sub-group of patients.

Characterization of Left Atrial Tachyarrhythmias in Patients Following Atrial Fibrillation Ablation: Correlation of surface ECG with Intracardiac Mapping

Catheter based ablation has become a popular treatment strategy in the management of patients with atrial fibrillation (AF). Although patients undergoing AF ablation can expect success rates in excess of 80%, 1-3 the procedure is associated with a small risk of complications, the commonest of which is the development of organized atrial tachyarrhythmias i.e., atrial tachycardias (AT) and / or flutters.4 The latter includes both typical (isthmus dependent) and atypical (usually left atrial) flutter circuits. Common to all of these tachycardias is the presence of well defined, regularly occurring “P” waves which may help with localization as well as provide insights into arrhythmia mechanism(s). Ultimately this information has implications for successfully mapping and ablating the tachycardia. The purpose of this paper is to provide the readers with a concise overview on the various organized atrial tachyarrhythmias seen post AF ablation and discuss their ECG manifestations vis-à-vis information obtained from intracardiac mapping / ablation.

Preparing The Electrophysiology Lab to Treat Atrial Fibrillation

In the past few years every lab has been looking for new procedures to perform. The latest procedure is Atrial Fibrillation due to the number of patients which has this arrhythmia. Besides just ordering the catheters needed for treatment of atrial fibrillation, the equipment in the electrophysiology lab is another important aspect of performing this procedure safely and efficiently.

Rate versus Rhythm Control Pharmacotherapy for Atrial Fibrillation: Where are We in 2008?

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance encountered by physicians. The management of AF is focused on control of heart rate, correction of rhythm disturbance, and risk-determined prophylaxis of thromboembolism. The goals of AF therapy are, as with other serious disorders, to reduce mortality (if possible) and mortality (improve quality of life, [QOL]). To this end, several large studies have examined rhythm-control versus rate-control strategies. Although a survival advantage to using rhythm control with currently available antiarrhythmic drugs has not been proven, neither has there been a significant excess risk versus rate control. Therefore, using our current therapies, the results have not supported rate control or rhythm control as being a preferable first-line therapy for AF as regards survival; importantly, neither do they disprove the hypothesis that maintenance of sinus rhythm is preferable to the continuation of AF, particularly if rate control fails to restore adequate QOL. Many post-hoc analyses and substudies have assessed QOL, functional status, and exercise tolerance, with the majority demonstrating important benefits associated with achievement of rhythm control. This review examines rate and rhythm control options, the clinical outcomes of several important AF trials, discusses the limitations in applying the major morbidity/mortality findings to everyday clinical practice, and summarizes the lessons learned.

Surgical Treatment of Atrial Fibrillation.

Atrial fibrillation (AF) is now commonly treated
at the time of valvular heart surgery or coronary artery bypass grafting. Surgical
ablation of AF, which is predicated upon the Maze procedure, includes creation
of lines of conduction block and excision of the left atrial appendage. A full bi-atrial lesion set is associated
with success in 80% to 95% of patients and virtually eliminates the risk of
late stroke. A complex but safe
operation, the classic cut-and-sew Maze procedure has been applied by
relatively few surgeons. However, recent
advances in understanding of the pathogenesis of AF and development of new
ablation technologies enable surgeons to perform pulmonary vein isolation,
create linear left and right atrial lesions, and remove the left atrial
appendage rapidly and safely. Lesions
are created under direct vision, minimizing the risk of damage to the pulmonary
veins and adjacent mediastinal structures. Recently developed instrumentation now enables thoracoscopic and keyhole
approaches, facilitating extension of epicardial AF ablation and excision of
the left atrial appendage to patients with isolated AF and no other indication
for cardiac surgery. In addition, novel
devices designed specifically for minimally invasive epicardial exclusion of
the left atrial appendage will broaden the range of treatment options for
patients with AF, possibly eliminating the need for anticoagulation in selected

Evaluation of Atrial Fibrillation

Identification of Atrial

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia
characterized by uncoordinated atrial activation. On the ECG fibrillatory (f)
waves (rapid oscillations with variable amplitude, shape and timing) replace
normal P waves. Ventricular response becomes irregular and rapid depending of
the intrinsic electrophysiological properties of the AV node
1 and the balance between vagal and sympathetic

The presence of an irregularly pulse is a clinical sign that can be
quickly and reliably identified in any healthcare situation and, indicates AF with
a high sensitivity and specificity (95% and 75%, respectively). If the
irregularity last for more than 20 seconds the specificity reaches 98%
2-4. Identification of AF can be done by using
manual pulse palpation in those presenting with a variety of symptoms. It is
desirable to check the blood pressure and pulse in all patients who present
with breathlessness, dyspnea, palpitations, syncope, dizziness or chest
discomfort. Furthermore, many patients presenting with an acute stroke are
found to be in AF albeit asymptomatic with respect to non-neurologic

The finding of a sustained irregular wide QRS complex tachycardia may be
suspicious of AF conducted with bundle brunch aberrancy or over an accessory pathway,
and in patients with A-V sequential pacemakers can reflect an inadequate
configuration with ventricular tracking of sensed atrial activity.

Transesophageal echocardiography for detection of left atrial appendage thrombi: Is it good enough?

Transesophageal echocardiography (TEE) has been considered the gold standard for visualization of left atrial appendage thrombi prior to electrocardioversion in patients with atrial fibrillation1.We report two cases in which 64-slice computed tomographic angiography (CTA) demonstrated prominent left atrial appendage thrombi in spite of a negative transesophageal echocardiogram.