Ventricular arrhythmias: use of electrophysiologic studies

The clinical utility of electrophysiologic testing in assessing the long-term efficacy of amiodarone for treatment of life-threatening ventricular arrhythmias is controversial, most investigators reporting little or no correlation between the early effects of the drug on arrhythmia inducibility and subsequent prognosis. We have evaluated 69 consecutive patients given amiodarone for ventricular tachycardia (VT) or fibrillation (VF). All patients underwent provocative electrophysiologic testing with programmed electrical stimulation before and after amiodarone loading. After a standardized amiodarone loading regimen, the patients' arrhythmias were not inducible in 22 patients (group 1) and remained inducible in 47 patients (group 2). No patient in group 1 has had a recurrence of VT/VF, whereas 15 (32%) of 47 patients in group 2 have had recurrences. The characteristics of the arrhythmia induced by programmed stimulation in group 2 accurately predicted the severity of the recurrence. We conclude that electrophysiologic testing may be useful in evaluating the efficacy of amiodarone for the long-term treatment of VT/VF and that its precise role in this context should be further investigated by stringently controlled studies.