| abstract |
formula: (Wherein ring X represents benzene or pyridine, R 1 represents substituted alkyl, R 2 represents optionally substituted aryl or an optionally substituted heterocyclic group, and R 3 represents hydrogen or Represents alkyl, R 4 represents hydrogen, halogen or alkyl, R 5 represents hydrogen or alkyl, and R 6 and R 7 are the same or different and each represents hydrogen or halogen.) Or a pharmaceutically acceptable salt thereof is useful as an I Kur blocker useful for the prevention or treatment of cardiac arrhythmias such as atrial fibrillation. |