Of the @ patients enrolled in the ADVANCE III trial , @ received a defibrillator for secondary prevention ; @ patients were randomly assigned to a long detection setting ( @ of @ intervals ) and @ to the nominal setting ( @ of @ intervals ) for ventricular arrhythmias with cycle length @ ms. Eight-five percent of patients were men , with a mean age of @ @ years , a previous history of ventricular fibrillation in @ % of the cases , and a mean ejection fraction of @ @ % .