Patients at lower risk of arrhythmia recurrence: A subgroup in whom implantable defibrillators may not offer benefit

OBJECTIVES The goal of this study was to identify subgroups of arrhythmia p atients who do not benefit from use of the implantable cardiac defibrillato r (ICD). BACKGROUND Treatment of serious ventricular arrhythmias has evolved toward more common use of the ICD. Since estimates of the cost per year of life sa ved by ICD therapy vary from $25,000 to perhaps $125,000, it is important t o identify patient subgroups that do not benefit from the ICD. METHODS Data for 491 ICD patients enrolled in the Antiarrhythmics Versus Im plantable Defibrillators Study were used to create a hazards model relating baseline factors to time to first recurrent arrhythmia. The model was used to predict the hazard for recurrent arrhythmia among all trial patients. A priori cut points provided lower and higher recurrent arrhythmia risk stra ta. For each stratum the incremental years of life due to ICD versus antiar rhythmic drug therapy were calculated. RESULTS Factors that predicted recurrent arrhythmia were: ventricular tachy cardia as the index arrhythmia, history of cerebrovascular disease, lower l eft ventricular ejection fraction, a history of any tachyarrhythmia before the index event and the absence of revascularization after the index event. Survival times (over a follow-up of three years) were identical in each ar m of the lowest risk sextile (survival advantage 0.03 +/- 0.12 [se] years), while the survival advantage for patients above the first sextile was 0.27 +/- 0.07 (se) pears (two-sided p = 0.05). CONCLUSIONS Patients presenting with an isolated episode of ventricular fib rillation in the absence of cerebrovascular disease or history of prior arr hythmia who have undergone revascularization or who have moderately preserv ed left ventricular function (left ventricular ejection fraction > 0.27) ar e not likely to benefit from ICD therapy compared with amiodarone therapy. (J Coll Cardiol 2001;37:1093-9) (C) 2001 by the American College of Cardiol ogy.