TY - CHAP M1 - Book, Section TI - Antidysrhythmic Drugs A1 - Suyderhoud, Johan P. A2 - Freeman, Brian S. A2 - Berger, Jeffrey S. PY - 2014 T2 - Anesthesiology Core Review: Part One Basic Exam AB - Antidysrhythmic agents, which are also known as antiarrhythmic agents, are a broad category of medications that help ameliorate the spectrum of cardiac arrhythmias to maintain normal rhythm and conduction in the heart. Arrhythmias generally arise as a result of abnormal impulse generation or abnormal conduction, or a combination of the two. Abnormal impulse generation falls into one of two categories: abnormal automaticity or triggered activity. Abnormal automaticity is thought to occur due to reduced resting membrane potential, causing the membrane to be closer to the threshold for generating an action potential. Triggered activity, or after-depolarization, occurs during the early stages after depolarization, such as in phase 2 and 3, or in the later stage during phase 4. With either form, it requires a preceding triggering beat to create the abnormal depolarization. Abnormal conduction is usually due to conduction block or a reentry phenomenon, with the latter being the most common cause of dysrhythmias. Antidysrhythmics exert their effect on specific ion channels on the cardiac cell membrane which then alters the shape of the action potential, and thus have inotropic, chronotropic, and toxic actions as a result. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/04/19 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1102569715 ER -