Major European study of device therapy aimed at preventing permanent atrial fibrillation

ORLANDO, Nov. 6  – A multinational European study found that using a cardiac resynchronization therapy (CRT) device to provide overdrive atrial pacing does not prevent patients with heart failure (HF) from developing permanent atrial fibrillation (AF).  The results were presented in a late-breaking clinical trial session at the American Heart Association’s Scientific Sessions 2007.

MASCOT is a prospective, randomized, controlled trial of HF patients enrolled from centers in Italy, France, Belgium, Germany and Greece.  The study population was 79 percent male, with a mean age of 68 years.  There were 197 patients in the treatment arm and 197 patients in the control arm.  The treatment arm added atrial overdrive pacing (pacing above the patient’s own atrial rate) to CRT, which uses ventricular pacing to improve heart function.

“This is the first prospective randomized study to analyze the effects of using a CRT device to prevent the development of AF in HF patients,” said Luigi Padeletti, M.D., the study’s principal investigator and professor of cardiology and director of the Postgraduate School of Cardiology, University of Florence, Italy.

The one-year results of the two-year study demonstrate the device is safe, and the programmed algorithm is safe in patients with serious heart failure, New York Heart Class III or IV, and a left ventricular ejection fraction of 35 percent or less.  However, the study did not find any statistically significant difference between the development of permanent AF in the treated and control groups (3.3% in both).

Researchers found a trend toward reduced mortality in the treated versus control group, with 7.6 percent mortality in the treated group compared to 11.7 percent mortality in the control group, but the difference was not statistically significant.

Support for this study was provided by St Jude Medical.

Statements and conclusions of study authors that are presented at American Heart Association scientific meetings are solely those of the study authors and do not necessarily reflect association policy or position.  The American Heart Association makes no representation or warranty as to their accuracy or reliability.

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