hERG (KCNH2 or Kv11.1) K+ channels: screening for cardiac arrhythmia risk.

Testing new compounds for pro-arrhythmic potential has focused in recent years on avoiding activity at the hERG K+ channel, as hERG block is a common feature of many pro-arrhythmic compounds associated with Torsades de Pointes in humans. Blockers of hERG are well known to prolong cardiac action potentials and lead to long QT syndrome, and activators, although rarer, can lead to short QT syndrome. The most reliable assays of hERG utilize stable cell lines, and include ligand binding, Rb+ flux and electrophysiology (both automated and manual).