Derivatives pharmaceutically acceptable thereof, or a salt thereof or a compound of formula (I) are provided: wherein, A represents a chemical moiety represented by the general formula (II) formula, X, CH is selected from the group consisting of 2, C (= O), CH (R 5), C C (R 5) or (R 6) (R 5) from (R 6) CH 2, R 1 is optionally substituted is selected from the group consisting of heteroaryl alkyl optionally substituted aryl and alkyl, which may be, R 2 is a group consisting of NR 7 R 8, or heteroaryl which may be substituted or aryl which may be substituted is selected from, R 3 is selected from the group consisting of nitrile or aminosulfonyl optionally substituted amino, can be optionally substituted alkyl, optionally substituted hydrogen, halogen, hydroxyl, alkoxy, aryloxy, optionally substituted is, R 4 is substituted sulfonyl acyl, optionally substituted heterocycloalkyl alkyl, optionally substituted cycloalkyl, and optionally substituted alkyl, optionally substituted hydrogen, optionally substituted , is selected from the group consisting of optionally substituted heteroaryl and optionally substituted aryl and alkyl, optionally substituted aryl, and optionally substituted sulfamoyl, optionally substituted optionally substituted, R 6 and R 5 are each It is alkyl which may be substituted, and are the same or different, optionally cycloalkyl, R 8 and R 7 may be optionally substituted alkyl and optionally substituted hydrogen, optionally substituted respectively represents heteroaryl optionally substituted aryl or alkyl aryl, optionally substituted, n is 1 or 2. There is also provided a pharmaceutical composition comprising said compound. These compounds are useful in the treatment of a variety of conditions including arrhythmia.式(I)の化合物もしくはその塩またはこれらの製薬上許容されうる誘導体が提供される:式中、Aは、一般式(II)で表される化学部分を表し;式中、Xは、CH2,C(=O),CH(R5),C(R5)(R6)またはC(R5)(R6)CH2からなる群より選択され、R1は、置換されていてもよいアリールアルキル、および置換されていてもよいヘテロアリールアルキルからなる群より選択され、R2は、置換されていてもよいアリールもしくは置換されていてもよいヘテロアリールまたはNR7R8からなる群から選択
