IDIOPATHIC VENTRICULAR-FIBRILLATION IN OUT-OF-HOSPITAL CARDIAC-ARRESTSURVIVORS

This study examined diagnostic and therapeutic roles of electrophysiol ogical testing and long-term clinical outcome after out-of-hospital ca rdiac arrest due to idiopathic ventricular fibrillation. This is defin ed as ventricular fibrillation occurring in the absence of detectable underlying heart disease or metabolic or electrolyte disturbance. Out- of-hospital cardiac arrest resulting from idiopathic ventricular fibri llation is uncommon. Records of all patients who underwent electrophys iological testing between June 1979 and June 1992 were reviewed. Patie nts with out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation were identified. Follow-up information was obtained by te lephone interview in June 1992. Of 194 patients who underwent electrop hysiological study after out-of-hospital cardiac arrest not associated with acute myocardial infarction, only six (4 male and 2 female) had idiopathic ventricular fibrillation. It was induced in only two patien ts by programmed ventricular stimulation. No sustained ventricular arr hythmias were induced in the remaining four patients. Four patients re ceived implantable cardioverter defibrillators, one was treated with a beta-adrenergic blocker, and one received no treatment. All patients were alive at a mean follow-up of 50 months. Two of the four patients without inducible sustained ventricular arrhythmias had events during follow-up. Of the two patients with inducible ventricular fibrillation , one experienced a cardiac arrest and documented ventricular fibrilla tion at 41 months after the index event and the other had had no recur rence at 15-month follow-up. All four patients with implantable cardio verter defibrillators were alive at last follow-up, and two had device discharges. In survivors of out-of-hospital cardiac arrest due to idi opathic ventricular fibrillation: (1) programmed electrical stimulatio n is of limited value for evaluating cause and guiding therapy; (2) a high rate of recurrent events is observed (50%); and (3) an implantabl e cardioverter defibrillator is effective for preventing a fatal outco me.