Medical Device Daily Contributing Writer

LA JOLLA, California — Former New York Yankee catcher and manager Yogi Berra, who was inducted into baseball's Hall of Fame in 1972, was famous for his many humorous expressions, sometimes known as "Yogi-isms." One of his best may have been that "you observe a lot by watching."

If Yogi has been watching recent developments in the field of atrial fibrillation (AFib), he would be observing a segment of the medical device industry that is emerging as a very hot area for investment and product development.

Within the last year, St. Jude Medical (SJM; St. Paul, Minnesota) has acquired EP MedSystems (West Berlin, New Jersey), which has a growing franchise in electrophysiology (EP) workstations and intracardiac echo (ICE), for $92 million and MediGuide (Haifa, Israel), which has developed a unique and proprietary tracking technology for a wide variety of interventional procedures, for more tan $300 million.

Meanwhile, its cross-town archrival, Medtronic (MDT; Minneapolis), purchased CryoCath (Montreal) late last year, which has developed a balloon catheter for atrial fibrillation ablation, for about $400 million and in February it announced the acquisition of novel AFib catheter developer Ablation Frontiers (Carlsbad, California). The latter deal was for $225 million in cash plus an estimated $175 million in additional milestone payments based on achieving various regulatory approvals.

Medical device industry observers have been stunned by the huge valuation premiums relative to comparable companies paid by SJM and MDT. However, the buying spree by these two cardiovascular juggernauts may ultimately be justified by the attractive dynamics of the global AFib market.

At St. Jude's annual investor conference, held in New York in early February, the president of the company's atrial fibrillation division, Jane Song, said that "after heart failure, atrial fibrillation represents the largest unmet clinical need in cardiovascular medicine today."

She indicated that the market for AFib procedures is barely penetrated by ablation-based therapies and that the number of procedures continues to grow rapidly. Specifically, Song estimated that the overall domestic cardiac ablation market which includes surgical ablations as well had nearly doubled from 40,200 procedures in 2005 to 78,000 in 2008. Despite the impressive 19% compound annual growth, this represented a mere 2.5% of the total number of AFib patients

There is no method to accurately tally AFib ablation procedures since all domestic AFib ablations have been performed off-label. Medical Device Daily estimates that roughly two-thirds of these ablations are catheter-based, with nearly all the remaining occurring concomitant to an open-heart revascularization or valve replacement procedure.

The first FDA AFib catheter approval was granted in early February (MDD, Feb. 9, 2009) to the Biosense Webster (Diamond Bar, California) division of Johnson & Johnson (New Brunswick, New Jersey). Its Navistar Thermocool catheter was cleared for the treatment of drug refractory recurrent symptomatic paroxysmal (intermittent) atrial fibrillation

The audience that gathered last Saturday to attend the Scripps Clinic (La Jolla, California) Percutaneous Catheter Ablation of Atrial Fibrillation conference heard from several of the world's experts in the AFib field. It was clear from their presentations that the AFib opportunity is huge and that technological developments are occurring at a speedy pace.

Course director Douglas Gibson, MD, director of the cardiac electrophysiology laboratory at Scripps Green Hospital (La Jolla), said that "percutaneous catheter ablation of AFib has conclusively proven to successful and ... has enjoyed tremendous growth in the last 10 years."

There has been rapid evolution of AFib mapping and ablation technologies in recent years, which has yielded new clues about this extraordinarily complex disease. Nevertheless, the protocols have evolved significantly and the procedure is still undergoing many changes.

Gregory Feld, MD, director of the EP program at the University of California San Diego Medical Center, gave a comprehensive review of the various ablation techniques for treating atrial fibrillation, noting that triggering of AFib from the pulmonary veins (PVs) is now "a well-accepted fact in the EP community."

He described three common approaches to treating AFib with catheter ablation, with two of them involving PV isolation. A third and emerging approach is doing a complex fractionated arterial electrogram (CFAE) ablation either alone or in combination with PV isolation.

Feld expressed caution on both the newly-approved Thermocool catheter, which he said "does not address the important question of tissue temperature" and the CryoCath/Medtronic balloon catheter, which he said does not appear to work in all pulmonary veins.

Andrea Natale, MD, executive medical director at St. David's Medical Center (Austin, Texas) and widely-regarded as one of the world leaders in this evolving field, spoke highly of a new ablation catheter, trade-named TactiCath, which has been developed by EndoSense (Geneva, Switzerland).

One of the key challenges that limits catheter ablation safety and efficacy is the physician's inability to accurately measure the contact force between the catheter and the beating heart wall. Without this measure, the physician has to estimate the level of force required. If the contact force is too great, the catheter tip may perforate the heart wall, which can create a serious problem. If it is too light, the procedure may be ineffective because the lesion is inadequate to stop the irregular electrical signals from being conducted in the atria.

In October 2008, EndoSense commenced the TOCCATA (TOuCh+ for CATheter Ablation) trial, a 70-patient European multi-center clinical study designed to evaluate the safety of the TactiCath. The company hopes that this trial will result in CE-mark approval later this year.

Another expert in the EP field, Vivek Reddy, MD, director of cardiac electrophysiology at the University of Miami Miller School of Medicine in Florida, delivered an outstanding talk on emerging ablation technologies. He was equally enthusiastic about the EndoSense catheter.

In addition, he praised the CryoCath balloon catheter because of its superb safety, but noted that its clinical efficacy was widely variable from one center to the next. Data from the pivotal trial, called STOP-AF, are expected in 2H09.

Reddy also had positive comments about the CardioFocus (Marlborough, Massachusetts) visually-guided laser balloon, which he said has been redesigned and now is much softer and compliant for better fitting into the pulmonary vein ostia. Initial clinic results look very promising and Reddy said he believes that this product could be a potential winner in this field.

He commented that the Ablation Frontiers data from Europe in treating persistent AFib is "encouraging, but safety issues are yet to be resolved."

Finally, a unique catheter that uses radiofrequency energy to heat up saline within a balloon was discussed. This device was developed by the medical division of the Toray Group (Tokyo).

Preliminary data from a group of Japanese EPs was presented at the November 2008 annual scientific sessions of the American Heart Association (Dallas). According to both Reddy and Natale, Toray has recently applied to the FDA to begin a U.S. feasibility trial.

In an interview with MDD after the conference, Feld said, "While we have made tremendous progress in recent years, there still is opportunity for further improvements in atrial fibrillation catheter technologies."

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