Unfavorable outcome in patients with primary electrical disease who survived an episode of ventricular fibrillation.

BACKGROUND: Prognosis in patients with ventricular tachyarrhythmia without structural heart disease (primary electrical disease) has been described as excellent. However, prognosis may be less favourable in the subgroup surviving an episode of ventricular fibrillation. METHODS AND
RESULTS: We prospectively followed 19 consecutive patients (age, 13 to 66 years; mean age, 33 years) who had survived an episode of documented ventricular fibrillation. Structural heart disease, preexcitation, and long QT syndromes were excluded by thorough cardiologic evaluation. All patients underwent 24-hour Holter monitoring, exercise testing, and programmed electrical stimulation according to a standardized protocol. Holter monitoring revealed episodes of ventricular tachyarrhythmia in 5 patients. Exercise testing reproducibly provoked ventricular tachycardia in 2 patients. Baseline programmed electrical stimulation yielded inducibility of rapid ventricular tachyarrhythmia in 10 patients (53%) and noninducibility in 9 (47%). Nine patients were discharged on antiarrhythmic drug therapy. A defibrillator was implanted in 10 patients. During 43-month follow-up (range, 5 to 85 months; median, 41 months), major arrhythmic events recurred in 7 patients (37%). Four of these patients had noninducibility at baseline programmed electrical stimulation. Two patients on antiarrhythmic drugs had recurrent cardiac arrest: one died suddenly and the other was successfully resuscitated from ventricular fibrillation and subsequently underwent defibrillator implantation. In the other 5 patients, termination of (pre)syncopal episodes was associated with defibrillator shocks. Termination of ventricular fibrillation was documented by Holter recording in one of these patients. Specific markers predictive of a recurrent event could not be identified, although 6 of 7 patients with recurrent events had experienced at least one episode of cardiac arrest or (pre)syncope before the index episode.
CONCLUSIONS: Patients with primary electrical disease presenting with ventricular fibrillation are at high risk of recurrence of major arrhythmic events during long-term follow-up. Noninducibility at baseline study does not predict an uneventful course. Also, early defibrillator implantation should be considered in these patients.