Ventricular Tachycardia: Prediction of Aprindine With Intravenous Aprindine BORIS STRASBERG, MD EDWIN PALILEO, MD DARREL PRECHEL, MS ROBERT BAUERNFEIND, MD, FACC STEVEN SWIRYN, MD, FACC CHRISTOPHER R. WYNDHAM, MD, FACC RAMESH C. DHINGRA, MD, FACC RICHARD KEHOE, MD KENNETH M. ROSEN, MD, FACC Chicago, Illinois From the Section of Cardiology, Department of Medicine, Abraham Lincoln School of Medicine, University of Illinois. Chicago, Illinois. This study was supported in part by Grants HL 18794, HL 23566 and Training Grant HL 17378 from the National Institutes of Health, Bethesda, Maryland, and a grant from the Eleanor B. Pillsbury Resident Trust Fund. Manuscript received July 7. 1980; revised manuscript received October 6, 1980, accepted October 9. 1980. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Aprindine is an experimental antiarrhythmic agent useful for manage- ment of recurrent drug-resistant ventricular tachycardia. The drug exists for human use as both an intravenous and oral formulation. The half-life of the oral preparation varies from 13 to 50 hours,l often necessitating a 1 to 2 week inpatient trial before the efficacy of its oral administration can be adequately assessed. Because of this long trial period, we hy- pothesized that perhaps the response to intravenous aprindine might predict the response to oral aprindine. If this were the case, then patients could be preselected for oral aprindine therapy based on response to intravenous aprindine, with expectation of cure. In the present study, we tested the hypothesis that the response to intravenous aprindine predicts the response to oral aprindine. In addi- tion, we also made observations concerning characteristics of ventricular tachycardia that predict a successful response to this antiarrhythmic agent. Address for reprints: Boris Strasberg. MD. Methods Cardiology Department, University of Illinois Hospital, P.O. Box 6998, Chicago, Illinois 60680. Response to Oral Aprindine was administered both intravenously and orally to 25 patients with ventricular tachycardia refractory to conventional antiarrhythmic agents to test the hypothesis that the response to intravenous aprindine predicts the response to oral aprindine. Ten patients had incessant ven- tricular tachycardia and 15 had paroxysmal sustained inducible ventricular tachycardia. Eleven patients (43 percent) had conversion to sinus rhythm with in- travenous aprlndine (nine with incessant and two with paroxysmal sus- tained ventricular tachycardia). Thirteen patients (all with paroxysmal sustained ventricular tachycardia) manifested slowing of the tachycardia without conversion, whereas in one patient with incessant ventricular tachycardia, the tachycardia became less frequent and nonsustained after Intravenous aprindine. All 11 patients who had conversion to sinus rhythm wtth intravenous aprindine remained free of ventricular tachycardia during oral treatment with aprindine (at 2 weeks) and for a follow-up period of 2 to 38 months (mean 18 f 13). Of the 14 patients who did not have conversion to sfnus rhythm with intravenous aprindine, 12 had sponta- neous or inducible ventricular tachycardia, or both, at evaluation 1 to 2 weeks after initiation of oral aprindine. In conclusion, administration of intravenous aprindine to patients with ventricular tachycardia is helpful in predicting the subsequent response to oral aprindine. In addition, the pattern of ventricular tachycardia pre- dicted the response to aprindine; patients with incessant ventricular tachycardia tended to respond, and those with paroxysmal sustained ventricular tachycardia tended not to respond. zyxwvutsrqponmlkjihgfedcbaZ Selection of patients: Criteria for inclusion in this study were as follows: (1) the occurrence of chronic recurrent symptomatic ventricular tachycardia; (2) 676 March 1981 The American Journal of CARDIOLOGY Volume 47