CDU Executive Editor

BOSTON, Massachusetts – The biggest trial for many of those who gathered to hear presentations during the "Late-Breaking Trials" segment that highlighted the closing sessions of the North American Society for Pacing and Electrophysiology (NASPE; Natick, Massachusetts) annual meeting was finding a vantage point from which to see and hear the results.

A standing-room-only crowd in Ballroom A of the Hynes Convention Center in Boston's trendy Back Bay swelled to a sitting-in-the-aisles and straining-to-listen-from-outside-the-doors crowd by the time the presenters of findings in several key clinical studies hit full stride. What they heard is that electrophysiologists who may soon be able to ADOPT some recently developed therapies for their patients will get results that are, well, nothing short of a MIRACLE.

Mark Carlson, MD, of Case Western Reserve University and University Hospitals (Cleveland, Ohio), reported on the ADOPT-A (Atrial Dynamic Overdrive Pacing Trial) study involving St. Jude Medical's (St. Paul, Minnesota) Dynamic Atrial Overdrive (DAO) algorithm, designed to suppress both brief and persistent episodes of atrial fibrillation. The ADOPT-A trial studied use of the proprietary technology in pacing, and Carlson said that the 196 patients who had been implanted with a pacemaker in which the AF-suppression feature was turned on showed a decrease in AF burden compared to the 203 trial participants in which DAO was left off.

He noted that 90% of atrial episodes suffered by trial participants were due to atrial fibrillation, nearly 5% to atrial flutter and just over 5% to a variety of other causes. Carlson noted that DAO "adjusts the pacing rate to the patient's intrinsic pacing rate," and he emphasized in response to a question from the audience that "programming [of the device used] was particularly important to the effectiveness of this therapy."

In another presentation that drew obvious interest from the packed house, William Abraham, MD, of the University of Kentucky (Lexington, Kentucky), followed up on a presentation he had made at the American College of Cardiology's (ACC; Bethesda, Maryland) annual scientific sessions in Orlando, Florida, in March with some new data from the MIRACLE (Multi-center InSync Randomized Clinical Evaluation) trial.

That trial, studying the effectiveness of Medtronic's (Minneapolis, Minnesota) InSync biventricular pacing device in patients suffering from chronic heart failure, showed very positive results, both in the early results presented at ACC and in the extended results Abraham presented at NASPE.

He noted that the NASPE session featured results from 366 patients, representing the crossover of all trial participants to InSync therapy after the first six months of being randomized into "on" and "off" groups. Simply put, the results presented by Abraham show that cardiac resynchronization therapy (CRT) provided by the InSync biventricular pacing device works. "CRT has emerged as a promising new treatment for heart failure patients," he said, noting that the "device on" group experienced a 65% improvement in composite response to treatment, compared to a 39% improvement in the control arm, the latter of which may have been attributed in large measure to the placebo effect often experienced in clinical trials.

In what he termed "the most significant of the new data" presented for the first time at NASPE, Abraham said that those in the CRT arm of the trial had a 62% smaller total of "all-cause hospitalizations," compared to the control arm, and a whopping 81% reduction in hospital days for heart failure causes.

He noted that cardiac resynchronization therapy is well-tolerated and improves a patient's quality of life, functional classification under New York Heart Association guidelines, exercise capacity and cardiovascular structure and function.

In another report, this one on the MUSTIC (Multisite Stimulation in Cardiomyopathies) trial conducted at 17 centers in six European countries, Cecilia Linde, MD, PhD, of Karolinska Hospital (Stockholm, Sweden), said that patients undergoing biventricular pacing experience four times fewer hospitalizations for atrial fibrillation causes. She said that biventricular pacing "significantly improves exercise tolerance and quality of life and reduces the need for heart failure-related hospitalizations."

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