《pharmacology of antiarrhythmics抗心律失常药理学》由会员分享，可在线阅读，更多相关《pharmacology of antiarrhythmics抗心律失常药理学（45页珍藏版）》请在金锄头文库上搜索。
1、PHARMACOLOGY OF ANTI-ARRHYTHMICS,Arrhythmia (a-rhythm) means no rhythm,whereas dysrhythmia (dys-rhythm) means an abnormal heart rhythm. In practice,both terms are used interchangeably to mean an abnormal of irregular heart beat.,Arrhythmia,Cardiac arrhythmias,Genesis of Normal Heart Rhythm,Genesis o
2、f Tachyarrhythmia,Antiarrhythmic Drugs,Managing Tachyarrhythmias,Heart Rhythm,Genesis of Normal Heart Rhythm: The Myocardial Action Potential,(1) pacemaker activity (2) absence of fast Na+ current in SA and AV nodes, where slow inward Ca2+ current initiates action potentials. (3) long action potenti
3、al (plateau) and refractory period (4) influx of Ca2+ during the plateau.,Electrophysiological Features,Phase-4 Depolarization results in automaticity of the cardiac action potential, in normal SA nodal cells.,The Effective Refractory Period(ERP),Genesis of Normal Heart Rhythm : Ion Channel,Genesis
4、of Tachyarrhythmia,Classification of Arrhythmias Bradyarrhythmias Tachyarrhythmias,Unidirectional Block and Reentry,Late After Depolarization,Sufficient Preparation,Depress resting membrane potential,Prolong Effective Refractory Period,Suppress enhanced automaticity,Slow conduction in tissue,Managin
5、g Tachyarrhythmias: Strategies,Classification of Antiarrhythmic Drugs (Vaughan-Williams),Classification of antiarrhythmic drugs,Class I: Na+ Channel Blockers,Class I: Na+ Channel Blockers,Guinidine,Class II Antiarrhythmic Drugs:,1-adrenoceptor blockers,How Sympathetic Stimulation Increases Heart Rat
6、e and Accelerates Conduction:,Non-pacemaker Tissue: Sympathetic activityAccelerated Conduction,Pacemaker:- adrenoceptor stimulation: automaticity,Class II: -adrenergic Blockers: Oppose effects of sympathetic tone, Reduce automaticity (including physiological) Slow conduction Mainly active in atrial
7、& atrioventricular tissue Reduce risk of sudden death after heart attack,Class II: Examples, Propranolol Metoprolol many other -olols Other aspects of pharmacology: look up autonomic pharmacology notes,Class III:,Drugs that Prolong Action Potential Duration & ERP,Class III: Examples, Amiodarone 胺碘酮
8、Sotalol 索他洛尔 (also -blocker),Class IV,Calcium Channel Blockers (also active in angina and hypertension),Adenosine, Adenosine receptors on atrial myocardium and atrioventricular conducting tissue K+ channels are adenosine receptor-linked,Adenosine: Pharmacology, Very rapid hydrolysis in blood only IV use rapid IV bolus For supraventricular tachycardias (may help diagnosis),Effects of antidysrhythmic drugs on the different phases of the cardiac action potential,Thank you!,
