Clinical evaluation of new antiarrhythmic agents: experiences with propafenone

The authors propose a general design for the clinical evaluation of new antiarrhythmic agents with special reference to their experience with propafenone, a new Class 1 agent. The drug was studied in 61 patients affected by PSRT, VEBs or RVT often unresponsive to other drugs. Both acute i.v. sensitivity tests and evaluation of chronic oral treatment were carried out. The results indicate that propafenone is a highly effective drug and that its oral activity may be predicted in individual patients by an acute i.v. administration. The most frequent adverse reaction was a widening of QRS complex. However the drug had to be withdrawn due to impaired intraventricular conduction in one patient only. More frequently (four cases) its withdrawal was due to adverse extracardiac reactions.