Catheter Ablation for Atrial Fibrillation

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Catheter ablation for atrial fibrillation (AF) is investigational and has not been approved for treatment by the US Food and Drug Administration.

Catheter ablation has been used on various types of cardiac arrhythmias since the 1980s, but has been effective on only certain heart arrhythmias. On arrhythmias such as Wolff-Parkinson-White (WPW) syndrome, right atrial flutter and supraventricular tachycardia (SVT), catheter ablation has been a successful form of treatment. The procedure was introduced as a treatment option for atrial fibrillation in the 1990s; however, in this capacity it has been less effective.61, 62

Catheter Ablation Procedures

Based on the classification of atrial fibrillation being treated, the catheter being used, the type of blood thinners introduced during the procedure, technique preferences of the electrophysiologists, and other variations, there are varying techniques and procedures for catheter ablation. However, even varying procedures generally follow the same protocol.  Multiple catheters are surgically inserted into a femoral vein in the leg or groin area and are then moved through the circulatory system up into the chambers of the heart. 

Once the catheters reach the heart, the septal wall (the wall between the two atria of your heart) is punctured and a guide wire is advanced into the left superior vena cava. The catheter tip is then advanced into the left atrium using the guide wire, and the catheter tip creates a lesion, usually using an energy source to isolate the pulmonary veins.  Catheter ablation can also be used in right atrial compartmentalization, left atrial compartmentalization, and to ablate focal triggers in both atria. 

 

 

Catheter Ablation Success Rates64

There have been no large, randomized multi-center trials to determine the safety and efficacy of catheter ablation as a treatment option for atrial fibrillation. Therefore, the success rates for this procedure vary based on different aspects of the individual trials. The most important aspect that can influence trial results is the patient population. The outcomes of AF ablation differ considerably depending on whether patients have paroxysmal, persistent or long-standing persistent atrial fibrillation. Other factors that can affect trial outcomes include age, concomitant cardiac disease, and LA (left atrium) size. 

To compensate for the variation among trials, the 2007 HRS guidelines looked at results from three sources when compiling success rate information for catheter ablation of atrial fibrillation. The three sources were non-randomized clinical trials, randomized clinical trials, and a physician survey. 

Non-randomized Clinical Trials

Each of these trials reported results from multiple ablation strategies or from single ablation strategies. For patients who underwent a single ablation, success rates ranged from 16% to 84% for mixed types of atrial fibrillation. In looking at specific types of AF, success rates ranged from 38% to 78% for paroxysmal patients (with the majority at 60% or greater) and 22% - 45% for persistent patients (with the majority at 30% or less).64 

Randomized Clinical Trials

Five randomized clinical trials for catheter ablation of atrial fibrillation have been performed since 2005. The most recent trial compared catheter ablation to drug therapy in a group of patients with paroxysmal AF. Success was defined as absence of symptomatic or documented atrial fibrillation for greater than or equal to three minutes. Patients were monitored at three, six, and twelve months after having up to three ablation procedures. At one year, the trial reported that 75% of patients were successfully free from atrial fibrillation as compared with only 7% success for those patients treated only with drug therapy.82

Physician Survey Results

In 2005, a worldwide survey completed by more than 180 centers on the methods, efficacy, and safety of catheter ablation was published. Each center that participated performed catheter ablations on paroxysmal patients; 53% performed ablations on persistent AF; and 20% performed ablations on permanent AF. In 27% of patients, more than one procedure was performed. The overall success rate, defined as freedom from symptomatic atrial fibrillation in the absence of antiarrhythmic therapy was 52%. An additional 24% of patients were free from symptomatic AF in the presence of a previously ineffective antiarrhythmic drug.64 

Summary of Results

The studies reviewed by the HRS guidelines provide evidence that catheter ablation is an effective means of treatment for atrial fibrillation. However, they also show that outcomes of this procedure can vary considerably depending on a number of factors. It is also important to recognize that catheter ablation of atrial fibrillation is a demanding technical procedure that may result in complications. Patients should only undergo AF catheter ablation after carefully weighing the risks and benefits of the procedure.64

Your electrophysiologist will be able to discuss all of the risks involved with a catheter ablation procedure and can help you decide if it is a viable treatment option based on the type of atrial fibrillation you have, your overall health, and medical history.