Introduction

Abstract

My introductory comments must trespass on aspects of the subsequent session, and points to be made by Dr Zipes. Though the British regulatory authorities appear to be somewhat more flexible than the Pood and Drug Administration, this is certainly not at the cost of quality in trials, and permission to investigate an antiarrhythmic agent requires full justification with sound documentation. If one can make out a case, assessment of response electrophysiologically to single intravenous injections is naturally easiest to obtain; and this can be done before long-term data on toxicity by the oral route has been obtained. This brings us immediately face to face with the question of extrapolation from what is seen with intravenous studies, in terms of termination of episodes and prevention of reinitiation, and the likelihood that this will point to oral efficacy or not. But this is by no means the whole story; for we may well encounter a preparation introduced for a different reason, that seems to have antiarrhythmic activity, and v/here the action of the agent given orally differs conspicuously from that seen when it is administered intravenously.