[Class-I antiarrhythmic drugs].

Classification, mechanism of action, pharmacokinetic properties and clinical applications of class-I antiarrhythmic agents were summarized. Class-I drugs were subdivided into three groups, Ia, Ib, Ic. This subclassification is based on their action to modify the action potential duration. In the Cardiac Arrhythmia Suppression Trial (CAST), flecainide and encainide were associated with greater mortality than placebo in patients with non-life threatening arrhythmias. Results of CAST and other megatrials suggested that antiarrhythmic agents were unsafe in some groups of patients and the limitation of antiarrhythmic therapy. Proarrhythmia and combination therapy of antiarrhythmic agents were mentioned.