Description: Amiodarone is an antiarrhythmic used to treat different types of tachyarrhythmias.
Electrophysiology: Class III antiarrhythmic (prolongs repolarization); lengthens cardiac action potential, negative chronotropic effect in nodal tissues, blocks myocardial K and Ca channels –> slows conduction speed in SA node, causes prolongation of refractory period.
Hemodynamic effects: IV amiodarone has a negative inotropic effect and causes peripheral vasodilation; 16% develop hypotension, 5% develop bradycardia.
Rapid infusion: hypotension and bradycardia (rate, not dose-related).
Tx: slow rate of infusion, fluids, vasopressors, chronotropic agents, or temporary pacing.