This issue of Cardiac Electrophysiology Clinics, edited by Drs. Mohammad Shenasa and Stanley Nattel, will review Cardiac Potassium Channel Disorders in depth. Topics covered include but are not limited to: Molecular Biology of Cardiac Potassium Channels; Genetic Control of Potassium Channels; Potassium Channel Remodeling in Heart Disease; Gender-specific Effects of Potassium Channel Blockers; Pharmacogenetics of Potassium Channel Blockers; Multichannel Blockers; Selective Potassium Channel Blockers; and Proarrhythmic and Torsadogenic Effects of Potassium Channel Blockers in Patients.