Antiarrhythmic Drugs Huifang tang Department of pharmacology Zhejiang University School of medicine anghuitang@zju.edu.cn
Antiarrhythmic Drugs Huifang Tang Department of pharmacology Zhejiang University School of Medicine tanghuifang@zju.edu.cn
A Electrophysiological basis of arrhythmias B Electrophysiological effects and classification of antiarrhythmic drugs C Antiarrhythmic drugs D Proarrhythmic effects of antiarrhythmic drugs
A. Electrophysiological basis of arrhythmias B. Electrophysiological effects and classification of antiarrhythmic drugs C. Antiarrhythmic drugs D. Proarrhythmic effects of antiarrhythmic drugs
A normal rhythm Rs premature ventricular beat C paroxysmal supraventricular tachycardia (PSVT) D atrial fibrillation arrhythmias v-y E atrial flutter with variable Av conduction Too rapid +++++++++++4+++++ atrial flutter with 1: 1 AV conduction Too slow; G monomorphic ventricular tachycardia Asynchronous; Reduce cardiac output H Torsades de Pointes ventricular fibrillation
arrhythmias Too rapid; Too slow; Asynchronous; Reduce cardiac output
A Electrophysiological basis of arrhythmias 1. Normal cardiac electrophysiology Excitability: ability to produce action potentials maximal diastolic potentials(MDP) threshold levels Automaticity: pacemaker phase 4 slope Conductivity: conduction pathways a phase 0 amplitude
A. Electrophysiological basis of arrhythmias ◼ 1. Normal cardiac electrophysiology ◼ Excitability: ability to produce action potentials ◼ maximal diastolic potentials (MDP) ◼ threshold levels ◼ Automaticity: pacemaker ◼ phase 4 slope ◼ Conductivity: conduction pathways, ◼ phase 0 amplitude
inward outward 0 Phase 4 Na+ current Action Ca -type current T-type potential transient ITO1 (4-AP-sensitive) and ion outward current To2 (Ca2+-activated) transport delayed ctifiers p inward rectifier, Ik1 Fast response cell pacemaker current, If (…, see above Na*-Ca2+ exchange Na′,K+ ATPase
Action potential and ion transport Fast response cell