Ventricular fibrillation in patients without significant structural heart disease: A multicenter experience with implantable cardioverter-defibrillator therapy

Objectives. This study was undertaken to characterize the outcome of survivors of ventricular fibrillation with no or minimal structural heart disease who received an implantable cardioverter-de fibrillator. Background. The prognosis among survivors of ventricular fibrillation with minimal or no structural cardiac abnormalities remains unclear. Since the advent of implantable cardioverter-de fibrillators, this question takes on added importance. Methods. This 10-center retrospective study provided information on 28 survivors of ventricular fibrillation (mean age 42 years) with minimal or no structural abnormalities who were treated with an implantable cardioverter-defibrillator. Results. Ventricular tachyarrhythmias (polymorphic in all but one patient) were induced during baseline programmed stimulation in 39% of patients. During a median 30.6-month follow-up period after importable cardioverter-defibrillator implantation, there were no cardiac deaths and two noncardiac deaths. Sixteen patients experienced 36 shock episodes (total 88 shocks). The majority of shocks were classified as "indeterminate"; one patient received 47 "spurious" shocks during one shock episode and each of four patients received one "appropriate" shock. Ventricular arrhythmias were not inducible in any of these latter four patients. Conclusions. Survivors of ventricular fibrillation with minimal or no structural cardiac abnormalities receiving an implantable cardioverter-defibrillator have an excellent 3-year survival rate. The occurrence, albeit infrequent, of appropriate implantable cardioverter-deflbrillator shocks in this group suggests that these patients have a potential risk of recurrent cardiac arrest whose fatal outcome may be avoided by implantable cardioverter-defibrillator therapy.