| 摘要 |
Disclosed is a compound which is useful in preventing and treating cardiac arrhythmia such as atrial fibrillation. A compound represented by formula (1) or a pharmaceutically acceptable salt of the same. In formula (1), ring X represents benzene or pyridine; R1 represents an optionally substituted alkyl group; R2 represents an optionally substituted aryl group, an optionally substituted heterocyclic group, an optionally substituted arylalkyl group or an optionally substituted heterocyclic group-substituted alkyl group; R3, R4, R5, R6, R7, R8 and R9 represent each hydrogen or an alkyl group, provided that R3 and R5 may be bonded to each other to form, together with the carbon atom adjacent thereto, a cycloalkyl group; and m represents 0 or 1. |
