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

Area of Science:

• Cardiovascular pharmacology
• Ion channel research
• Drug safety assessment

Background:

• Pro-arrhythmic drug potential is often linked to hERG K+ channel activity.
• hERG channel blockers can prolong cardiac action potentials, leading to Long QT syndrome.
• hERG channel activators, though less common, may cause Short QT syndrome.

Purpose of the Study:

• To outline current strategies for testing drug pro-arrhythmic potential.
• To emphasize the importance of hERG channel assessment in drug development.
• To highlight the need for integrated risk assessment for cardiac safety.

Main Methods:

• Utilizing stable cell lines for reliable hERG assays.
• Employing ligand binding, Rb+ flux, and electrophysiology (automated and manual) for hERG assessment.
• Conducting follow-up measurements on other cardiac ion channels and action potentials in cardiac tissue.

Main Results:

• hERG channel assays provide reliable data on compound activity.
• Assessing multiple ion channels and action potentials offers a comprehensive view of cardiac risk.
• Integrated risk assessment, considering channel activity and block kinetics, is key.

Conclusions:

• Avoiding hERG channel activity is a primary focus in pro-arrhythmic potential testing.
• A combination of hERG assays and other cardiac assessments is necessary for accurate risk evaluation.
• The interplay of ion channel activities predicts in vivo cardiac risk effectively.