Class III antiarrhythmic agents have a lot of potential but a long way to go. Reduced effectiveness and dangers of reverse use dependence.
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.
Hondeghem
L M
LM
Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232.
Snyders
D J
DJ
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*
D000889:Anti-Arrhythmia Agents; D015221:Potassium Channels; D015222:Sodium Channels