The effectiveness of implantable cardioverter defibrillators (ICDs) implanted in the early postoperative period after cardiac surgery for ventricular tachyarrhythmias is unknown, because all of the major trials excluded this patient population. Thus, a 10-year retrospective study was conducted of patients who had ICDs implanted for de novo postoperative ventricular tachyarrhythmias during the index admission for cardiac surgery. There was a high rate of early recurrence of ventricular tachyarrhythmia treated by defibrillators, and this finding questions the exclusion of this important patient population from large trials.