Dear Readers,

In the United States (U.S.), ablation catheters are required to be approved by the Food and Drug Administration (FDA) before they can be used for cardiac ablation. However, as most electrophysiologists realize, most ablation catheters are approved for limited indications such as ablation of atrial flutter, or generically for ablation of cardiac tissue. There are no catheters specifically approved for use during ablation of atrial fibrillation (AF). Instead, AF ablation procedures are performed using catheters that are labeled for use for other indications.

So-called “off-label” use of drugs and devices is at the discretion of the physician and is common in the U.S. However, there are several problems introduced by this practice. One problem that is pertinent to the field of cardiac ablation is the problem faced by industry when trying to develop novel tools for AF ablation. At this time, companies designing a study to determine the safety and efficacy of a new ablation tool cannot perform a randomized trial comparing their new device to currently used devices, because the currently used devices are not approved by the FDA for AF ablation. Therefore, companies are left to perform a randomized trial with antiarrhythmic drug therapy as the control arm. Unfortunately, it can be very difficult to enroll patients in these types of trials, because a large number of patients with AF who are referred to an electrophysiologist are refractory to drug therapy and are often expecting to be offered an ablation procedure. Slow enrollment in AF ablation trials is one reason for the lack of progress over the past decade in the development of a better tool for AF ablation.

For various legitimate reasons, electrophysiologists performing AF ablation have moved toward the use of cooled tip ablation electrodes. In the recent A4 study that compared catheter ablation to antiarrhythmic drugs for AF (published in Circulation in December 2008), 88% of the cases were performed using an irrigated tip electrode. Although most of the procedures in the A4 study were performed outside the U.S., the saline open-irrigated RF ablation catheter has become the standard catheter for AF ablation at many U.S. centers. It is remarkable, however, that not only has this catheter never been approved by the FDA for AF ablation, it has been approved only for ablation of type I atrial flutter and recurrent drug/device refractory sustained monomorphic ventricular tachycardia due to prior myocardial infarction in adults.