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

The value of serial electrophysiologic testing in predicting the outcome of patients receiving amiodarone is controversial. Thirty-six patients with drug-refractory sustained ventricular tachyarrhythmias underwent serial electrophysiologic drug testing. All patients had inducible sustained ventricular tachyarrhythmias off any antiarrhythmic medication. After an oral amiodarone loading regimen there was no change in inducibility in 23 patients (group I), whereas ventricular tachycardia was made more difficult to induce in 5 patients, i.e. sustained ventricular tachycardia was only inducible using a basic drive which was 40 bpm faster than during control (group II). In the remaining 8 patients, induction of ventricular tachycardia was suppressed (group III). During follow-up of 11 +/- 12.3 months, 6 patients in group I had a recurrence of ventricular tachycardia and 2 died suddenly, whereas the course of groups II and III patients was uneventful (P less than 0.03, Breslow; P less than 0.01, Mantel-Cox). The predictive accuracy of the response to serial electrophysiologic testing during amiodarone therapy was 64%, the sensitivity was 46% and the specificity 100%. Thus, serial electrophysiologic drug testing is useful in determining prognosis and predicts the long-term response to amiodarone therapy in patients with ventricular tachyarrhythmias using a graded stimulation protocol.