Novel K+ Channel Targets in Atrial Fibrillation Drug Development--Where Are We?

There is a clear unmet medical need for new pharmacologic therapies with improved efficacy and safety for the treatment of atrial fibrillation. Considerable research efforts have been undertaken to discover and develop new safe and effective antiarrhythmic drugs that specifically target atrial K(+) channels. To realize the full value of these novel atrial-specific therapeutic drug targets, demonstration of clinical efficacy and safety is required for a new breed of atrial-selective antiarrhythmic drugs. The reward for demonstrating this in a pivotal phase III trial, on regulatory approval, will be "first-in-class" status. This article reviews the development status of new and novel K channel inhibitors currently in drug development as atrial-selective antiarrhythmics for the treatment of atrial fibrillation.