[Myocardial refractory changes after single intravenous administration of cordarone (electrophysiologic study of the heart)].

In 29 patients with cardiac arrhythmias, refractory periods (RP) of the atrium, atrioventricular node and ventricle were defined before and after intravenous administration of cordarone in a dose of 5 mg/kg body weight. The effective RP (ERP) of the atrio-ventricular node showed the most profound changes: in 73% of the patients, the increase was 22.8% as compared to the pretreatment value. The most response of atrial RP to cordarone was also an increase of right atrial ERP by an average of 16.5%, FRP, by 13.1% versus the baseline values. The least effect was produced by cordarone on ventricular RP, namely the maximal increase in right ventricular FRP and ERP did not exceed 10%, but these parameters remained unchanged in a third of the patients.