Predictive value of electrophysiologic testing in the treatment of drug-refractory ventricular arrhythmias with amiodarone

The value of serial electrophysiologic testing in predictingthe outcome of patients receiving amiodarone is controversial.Thirty-six patients with drug-refractory sustained ventriculartachyarrhythmias underwent serial electrophysiologic drug testing.All patients had inducible sustained ventricular tachyarrhythmiasoff any antiarrhythmic medication. After an oral amiodaroneloading regimen there was no change in inducibility in 23 patients(group I), whereas ventricular tachycardia was made more difficultto induce in 5 patients, i.e. sustained ventricular tachycardiawas only inducible using a basic drive which was 40 bpm fasterthan during control (group II). In the remaining 8 patients,induction of ventricular tachycardia was suppressed (group III).During follow-up of II ± 12.3 months, 6 patients in groupI had a recurrence of ventricular tachycardia and 2 died suddenly,whereas the course of groups II and III patients was uneventful(P<0.03, Breslow; P<0.01, Mantel–Cox). The predictiveaccuracy of the response to serial electrophysiologic testingduring amiodarone therapy was 64%, the sensitivity was 46% andthe specificity 100%. Thus, serial electrophysiologic drug testingis useful in determinating prognosis and predicts the long-termresponse to amiodarone therapy in patients with ventriculartachyarrhythmias using a graded stimulation protocol.