[Electrophysiological effects of the antiarrhythmia agents disopyramide and propafenone on human heart conduction system].

The effect of Disopyramide and Propafenone on intracardiac conduction and refractory periods was tested by means of His bundle electrography and atrial stimulation. Disopyramide (1,7 mg/kg) was administered in 10 patients. There was no significant change of heart rate and conduction time within the atrium and the AV-node. The conduction velocity within the His-Purkinje system was significantly slowed by 13% of the control value. The ERP of the atrium as well as the ERP and FRP of the AV node were prolonged. Propafenone (1,7 mg/kg) was tested in 18 patients. The heart rate was significantly slowed by 13% of the control value. The conduction velocity within all compartments of the heart was depressed uniformly. The all-over-all prolongation of the HBE-intervals was 15%. Furthermore the results are in favour of a prolongation of the ERP of the atrium and the ERP of the AV node. The results can only partially explain the antiarrhythmic effect of the drugs. However, the data are important for assessing the possible side effects during antiarrhythmic treatment especially in patients with disease of the conduction system.