Chromanol 293B is primarily used in scientific research as a selective blocker of the slow delayed rectifier potassium current (IKs) in cardiac cells. This property makes it a valuable tool for studying cardiac electrophysiology, particularly in understanding the mechanisms underlying action potential prolongation and arrhythmias. It is commonly applied in in vitro studies using isolated heart tissues or cardiomyocytes to induce QT interval prolongation, serving as a model for Long QT Syndrome. Due to its specificity for the KCNQ1/KCNE1 potassium channel complex, Chromanol 293B helps researchers investigate the function and pharmacology of this channel without significantly affecting other major cardiac ion currents at low concentrations. Its use supports the evaluation of drug-induced cardiotoxicity and the development of safer pharmaceuticals.