Medtronic on Monday announced the enrollment of the first patient in its Victory AF clinical trial, a study involving patients with persistent or long-standing persistent atrial fibrillation. Patients in the trial will undergo a procedure with Medtronic's Phased Radiofrequency (RF) system. The study will evaluate the safety of the system, while collecting data on the system's effectiveness.

The system delivers customized radiofrequency energy to eliminate or block abnormal electrical impulses in the left atrium that initiate or sustain atrial fibrillation. The multi-electrode catheters are intended to allow doctors to identify and selectively ablate a broad area of heart tissue without the need for single-point catheters or complex mapping and navigation equipment.

The Medtronic Phased RF System is currently approved for use in areas of Europe, Asia, Africa, Australia, and Canada. More than 20,000 patients in 26 countries have been treated since January 2009. The system is not yet approved for sale in the United States.

Up to 350 patients will enroll in the trial at 40 centers in the U.S., Canada and Europe. The trial will examine the 30-day procedure-related stroke rate and device-related stroke rate. Six-month effectiveness, as well as rates of pulmonary vein stenosis and acute procedural success, will also be measured.

The principal investigator is Dr. Greg Michaud, assistant professor, Harvard Medical School, and director of the Center for the Advanced Management of Atrial Fibrillation at Brigham and Women's Hospital in Boston. The first patient in this study was recently treated by Dr. David DeLurgio of Emory University Hospital Midtown in Atlanta.

"In strong collaboration with the [U.S. Food and Drug Administration], we designed the VICTORY AF trial to evaluate the safety of Phased RF ablation in patients who suffer with persistent or long-standing persistent AF," said Reggie Groves, vice president and general manager of the AF Solutions division at Medtronic. "We expect this trial will demonstrate its safety and benefit for this patient population."

Persistent atrial fibrillation is defined as lasting more than seven days but less than one year, or lasting fewer than seven days but requiring treatment with medication or electrical current. Long-standing persistent AF is defined as lasting more than one year but fewer than four years.

In the United States, AF ablation catheters currently are available only for treating the mildest form of AF, in which the heart's upper chambers beat rapidly and irregularly during episodes lasting from a few minutes to a few days. AF can progress into a persistent or long-standing persistent state, where patients often cannot be effectively treated with medication. Patients with persistent and long-standing persistent AF can have debilitating symptoms and are at elevated risk for stroke, hospitalizations and reduced quality of life.