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 (I_Kur), acetylcholine-regulated inward rectifying potassium current (I_K-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 I_K-ACh inhibition are lacking at this time. The available data suggest that atrial-selective approaches involving a combination of I_Na, I_Kur, I_Kr, and, erhaps, I_to block may be more effective in the management of AF than pure IKur or I_Na 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.