EP Lab Digest - October 2007 - (Page 27)

OCTOBER 2007 CRYOTHERAPY UPDATE 27 because cryoablation has less risk of death and serious complications than radiofrequency ablation. Esophageal perforation has not been seen with cryoablation. In addition, pulmonary vein stenosis, which is another very difficult to treat problem that can occur with radiofrequency ablation, has not been seen with cryoablation. Although the mechanics of performing the procedure can be associated with certain complications, the more serious and difficult to manage complications do not appear to be occurring with cryo. Having said that, there is a risk of injury to the right phrenic nerve due to the proximity of the nerve to the right superior pulmonary vein. Freezeinduced palsy of that nerve can occur, as with other technologies.To mitigate the risk of damaging the phrenic nerve, we typically choose the larger 28 mm balloon and keep the balloon positioned as proximal as possible, and we continuously pace the phrenic nerve during any ablations that are in close proximity to the phrenic nerve. Nerve tissue also typically recovers well after freeze injury. I think the bottom line here is the potential simplicity of the procedure: by doing only a modest number of cryoapplications, one can get complete isolation of all 4 of the pulmonary veins in a very high percentage of patients. While it does require a considerable amount of operator skill in terms of performing a transseptal and manipulating catheters in the left atrium, I believe that the skill level is less than what is necessitated by some of the RF techniques, and certainly on a time basis, cryoablation techniques should allow the procedure to be performed much more rapidly simply because of the ability to cover larger areas and isolate a complete vein with perhaps as little as 1 or 2 applications of cryo energy. Ultimately, I believe we are on the cusp of a new technology. Hopefully balloon design enhancements will facilitate an even better balloon/vein interface for patients with challenging anatomies. Some patients have a common vein ostium that is larger than the 28 mm balloon. There are some unique challenges, but they are not insurmountable. also has a balloon as a component of the system; the difference is that in the case of cryo, the balloon itself is the delivery tool — that is what creates the freeze. Thus, the way that balloon interacts with the mouth of the pulmonary vein and the operator’s ability to create an occlusive seal to wedge the balloon up into the vein and produce a complete circumferential freeze is key to achieving a high degree of success with this technique. I believe other cryoballoons have been designed, although I’m not sure if any of those have progressed into human trials, and some of them have had problems with deployment and redeployment (i.e., pumping liquid nitrogen into the balloon, getting it back to the console, collapsing the balloon, and allowing it to be relatively easily manipulated to other vein locations in the atrium).This is the first product that I’m aware of where all of those elements have come together in a system that can be successfully used in people. This is a dramatically innovative product that may revolutionize how we in the electrophysiology lab manage AF patients. This is a dramatically innovative product that may revolutionize how we in the electrophysiology lab manage AF patients. I don’t think that paradigm is fully understood by many people, simply because the awareness of the data concerning Arctic Front and cryoablation hasn’t fully gotten out there. Although there are several hundred European patients who have been successfully treated at this time, there hasn’t been a large clinical trial such as this for the U.S. population. For someone like me, who runs an electrophysiology lab and has been doing AF ablation ever since 1999, it is incredibly exciting to use technology that has the potential to cure a very high percentage of patients.We’ve come to expect 95% success rates or greater with conventional ablations (e.g., AV node tachycardia or accessory pathways), and yet the field of atrial fibrillation has been very frustrating with success rates that can range anywhere from 50% up to 85%. A lot of this is because of the different subgroups of AF patients — paroxysmal, persistent and chronic. Having technology that levels that playing field and takes the average electrophysiologist and lets them become proficient at AF ablation is exciting. AF ablation is predominantly available now only in specialized centers, by electrophysiologists who have dedicated a significant amount of time learning the RF technique. Projecting forward into the future, I believe what we’ll see are hybridizations in which the Arctic Front approach of using a cryoballoon to create isolation of the pulmonary veins is done, and then concomitant with that, utilization of other ablative tools to create linear lines or perform adjunctive strategies such as fractionated potential ablation to deal with patients who have more persistent or permanent AF. In the end, the future is very exciting for this technology. What is the completion date for this trial? The completion date depends upon investigator enrollment. The company hoped that enrollment would be finished by the end of calendar year 2007; however, this is a complex protocol, and enrollment has been slower than predicted. It will take a year of follow up (after the last patient completes his follow up) until there is a complete data set to go to the FDA with for PMA approval. I would estimate that by early spring there is a good likelihood that all the patients will have been enrolled, and then we would have to wait for the follow up data to be collected. Therefore, it’s a product that the general electrophysiologist might not see available until potentially a couple of years. For more information about the STOP AF trial, please visit www.cryocath.com How can a doctor get a patient enrolled in this trial? In addition, how can a patient interested in the trial get information? The best way is for the physician to visit CryoCath’s website (www.cryocath.com) and click on the link to the STOP AF trial. There is a listing of the participating centers and the appropriate individuals to contact. There are centers all around the country that are offering this enrollment to their patients. Patients can also visit the website to get a trial description and a complete list of participating centers and contact information. Deadline for December Issue: Readers, there is still time to submit your article for our December 2007 issue of EP Lab Digest! To have your submission considered for publication, please email your article to “jelrod@hmpcommunications.com”. Have you visited “www.eplabdigest.com” lately? Use our site to: • Read the current EP Lab Digest issue online • Complete our salary survey (not much time left!) • Order reprints of articles • Submit a question and/or response to the Email Discussion Group • Download our Author Guidelines or Spotlight Interview Questionnaire • And much more! How is the STOP AF trial different from other balloon and AF trials? Let’s focus on cryo, because there are other balloons that have been used as part of the vehicle for delivering energy. One of the ongoing trials using laser has a balloon as an integral part of the system, and the high frequency ultrasound Is there anything else you’d like to add? http://www.cryocath.com http://www.eplabdigest.com http://www.cryocath.com http://www.cryocath.com

Table of Contents Feed for the Digital Edition of EP Lab Digest - October 2007

Finally! The New Registered Cardiac Electrophysiology Specialist (RCES) Credential: Interview with Christopher M. Nelson, RN, RCIS, FSICP ECG 101: Closing the Gap Phenomenon Contents Letter from the Editor ICD Patient Support Group: St. Peter’s Hospital Spotlight Interview: Community Healthcare System Use of Magnetic Catheter Navigation for Ablation of Focal Tachycardias Echocardiography: The Preeminent Front Line Screening and Diagnostic Tool for Cardiovascular Imaging and Physiological Assessment First Annual EP Lab Digest Salary Survey: Last Chance! Clinical Trial Update: 2007 Email Discussion Group Adopting and Implementing the AF Ablation Consensus Statement Electrophysiology in the West Summit Events Calendar The Sustained Treatment of Paroxysmal Atrial Fibrillation (STOP AF) Clinical Trial: Interview with Kevin Wheelan, MD Industry News and Products

EP Lab Digest - October 2007

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