St. Jude Medical, Inc. (NYSE:STJ) announced the results from the Substrate versus Trigger Ablation for Reduction of Atrial Fibrillation (STAR-AF) trial. The findings were presented during a late-breaking clinical trials session at Heart Rhythm 2009, the annual Heart Rhythm Society's Scientific Sessions in Boston.

The STAR-AF trial, sponsored by St. Jude Medical, was an open, randomized, prospective, multicenter clinical trial involving 108 patients, administered in several Canadian and European centers. Designed as a three arm trial, it compared the generally accepted treatment approach of pulmonary vein isolation (PVI), with complex fractionated electrogram (CFE) guided therapy, and with a third arm that combined the two therapies. The primary endpoint of the trial was relief of atrial fibrillation (AF) episodes of 30 seconds duration or greater, up to 12 months after treatment.

Study results indicate that after one ablation procedure, a combination of PVI and CFE guided therapy demonstrated significantly higher freedom from AF, at 74 percent, as compared to PVI alone at 47 percent and CFE guided therapy alone at 29 percent. Importantly, 94 percent of patients who received the combination of these treatments remained off any anti-arrhythmic medications at the end of the 12-month follow-up period.

Atrial fibrillation is a condition in which the upper chambers of the heart (atria) beat rapidly and erratically, affecting the heart's ability to adequately pump blood to its lower chambers (ventricles) and subsequently to the rest of the body. The STAR-AF trial studied patients with both symptomatic high burden paroxysmal (intermittent, but frequent and prolonged AF) and those with persistent AF. These two groups represent the largest subset of patients with AF; they experience varying degrees of intermittent AF episodes. The study participants had been unresponsive to medication that is meant to alleviate symptoms or the abnormal heart rhythm itself.

"While many unanswered questions remain about the origins of and best treatment options for AF, the results of STAR-AF indicate that perhaps traditional pathways are not the optimal ones. By mapping for the areas of CFE during AF ablation, we have demonstrated an incremental benefit for patients who historically may have undergone only a PVI," said Atul Verma, M.D., an electrophysiologist in the Heart Rhythm Program at Southlake Regional Health Centre in Newmarket, Ontario, Canada, who was the principal investigator in the study. "Moreover, I feel that using an automated method for identifying the areas of CFE removes some of the subjectivity that exists in accurately targeting those regions of interest, and may be useful to physicians as they perform AF ablation."

CFEs are highly random and chaotic electrical signals in the atria that may be a source of origin or perpetuation of AF - they are extremely difficult to identify accurately by visual inspection alone. Therefore, an automatic algorithm from St. Jude Medical's EnSite™ System was used to identify these regions in the patients randomized to receive this treatment course. The CFE guided therapy alone and hybrid PVI and CFE guided therapy strategies were being studied because often a PVI alone will result in either recurrence of AF or another complicated atrial rhythm that requires additional patient intervention.

"The results of the STAR-AF trial represent an important step toward understanding the best set of tools and therapies for treating cardiac arrhythmias, such as AF, and highlights St. Jude Medical's commitment to providing pioneering research to improve treatment of this condition," said Denis Gestin, president of the St. Jude Medical International Division. "Our sponsorship of this trial demonstrates our dedication to partnering with physicians to answer the many questions that exist about the treatment of AF."

AF is the most common abnormal heart rhythm and affects an estimated 2.3 million people in North America and 4.5 million Europeans. AF is responsible for 15 to 20 percent of all strokes, is a contributor to heart failure and is a leading cause of hospitalizations.

Heart Rhythm 2009 takes place May 13-16 at the Boston Exhibition and Convention Center. The meeting is the most comprehensive educational event on heart rhythm disorders, offering approximately 250 educational opportunities in multiple formats. The world's most renowned scientists and physicians will present a wide range of heart rhythm topics including cardiac resynchronization therapy, catheter ablation, cardiac pacing and heart failure and the latest technology, including state-of-the-art pacemakers and defibrillators. http://www.HRSonline.org.

Source
St. Jude Medical