A Electrophysiological basis of arrhythmias B Electrophysiological effects and classification of antiarrhythmic drugs C Antiarrhythmic drugs D Proarrhythmic effects of antiarrhythmic drugsA. Electrophysiological basis of arrhythmias B. Electrophysiological effects and classification of antiarrhythmic drugs C. Antiarrhythmic drugs D. Proarrhythmic effects of antiarrhythmic drugs