[The control of the atrio-ventricular reciprocating tachyarrhythmias. A preliminary electrophysiological study and comparison between amiodarone and verapamil (author's transl)].

The effects of amiodarone (2.5 mg/Kg i.v.) and of verapamil (0.1 mg/Kg i.v.) on refractory periods and on conduction of structures interested in the reciprocating circuit, as well as on the possible echo zones, were comparatively evaluated through electrophysiological test in 8 patients, four of which with W.P.W. from Kent bundle, and four with double A-V pass with reciprocating supraventricular tachicardia (RST) documented crises. None of the two drugs seems to have the theorical requirements of balanced effect to be chosen for the antiarrhythmic prophylaxis in patients with ventricular pre-excitement. In patients with double A-V pass, while both drugs have a sufficiently balanced and regular action on refractory periods and on conduction the irregularity of their effects on echo zones appears to restrict their validity in chronical therapy. According to the Authors, the only useful criteria for the choice of an antiarrhythmic drug for the prophilaxis of R.S.T. to be derived through extrapolation from these electrophysiological tests are: 1) the functional suppression of a circuit structure; 2) the evaluation of effects on echo zones; 3) the possibility or not the evoking R.S.T.