Class 4 antiarrhythmic drugs explained

Class 4 antiarrhythmic drugs are the calcium channel blockers (calcium antagonists) verapamil and diltiazem, used to treat supraventricular cardiac arrhythmias. This video explains the mechanisms of actions of these drugs, why they are effective as antiarrhythmic medicines, when they are used and the differences between verapamil and diltiazem. Learn about the specific drug target, its role in regulating heart rhythm at the sinoatrial node and the speed of conduction of electrical impulses through the atrioventricular node. This is a great resource for medical education and understanding cardiac pharmacology and physiology. Prior knowledge of the ionic basis of cardiac action potentials would help you gain the most from this lecture. This topic is explored in the following video:    • Cardiac action potentials: ionic mechanims...   00:00 Introduction 00:23 Classification of antiarrhythmic drugs 01:18 Voltage-gated calcium channels 03:18 Calcium channel blocker (CCB) 04:02 Calcium channels in the heart 04:40 Calcium channels in cardiac myocytes 06:40 Calcium antagonist effect on cardiac muscle 08:32 L-type Ca channels in cardiac node cells 10:28 Calcium antagonist effect on nodal cells 11:21 Use-dependence: a characteristic feature 13:30 Use-dependence explained 14:48 Binding kinetics and use-dependence 16:09 Clinical use of class IV antiarrhythmics 17:22 The class IV calcium channel blockers 20:32 Class IV antiarrhythmic drugs: Key points