title: Class III antiarrhythmic agents have a lot of potential but a long way to go. Reduced effectiveness and dangers of reverse use dependence.
abstract: With regard to currently available class III agents, although their class III effect may reduce the likelihood of tachycardia initiation, their reverse use-dependent prolongation of action potential duration reduces their effectiveness during tachycardias and may even render them proarrhythmic, especially after long diastolic intervals. In contrast, agents that exhibit normal use-dependent prolongation of refractoriness hold great promise: While having relatively less effects on the normal heart beat, they could induce self-termination of a tachycardia. Prolongation of refractoriness can be achieved by lengthening of action potential duration and delaying recovery of excitability. Combination of these drug actions may yield important clinical applications.
authors: Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232.
authors: L M
authors: LM
authors: Hondeghem
authors: D J
authors: DJ
authors: Snyders
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use / Q000633:toxicity; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008955:Models, Cardiovascular; D015221:Potassium Channels / Q000187:drug effects; D015222:Sodium Channels / Q000187:drug effects; D013610:Tachycardia / Q000188:drug therapy*
chemical_list: D000889:Anti-Arrhythmia Agents; D015221:Potassium Channels; D015222:Sodium Channels