The present invention provides new pyrrolobenzimidazoles of the general formula: ##STR1## wherein R.sub.1 is a hydrogen atom or an alkyl, alkenyl or cycloalkyl radical; R.sub.2 is a hydrogen atom, cyano group or alkyl or alkenyl radical or a carbonyl group substituted by hydroxyl, alkyl, alkoxy, amino, alkylamino, dialkylamino or hydrazino or together with R.sub.1 forms a cycloalkylene radical or R.sub.1 and R.sub.2 together form an alkylidene or cycloalkylidene radical; R.sub.3, R.sub.4 and R.sub.5, which can be the same or different, each represent a hydrogen atom or an alkanesulphonyloxy, trifluoromethanesulphonyloxy, alkanesulphonylamino, trifluoromethanesulphonylamino, N-alkyl-alkanesulphonylamino, N-alkyl-trifluoromethanesulphonylamino, alkylsulphenylmethyl, alkylsulphinylmethyl or alkylsulphonylmethyl radical, a carbonyl group substituted by hydroxyl, alkoxy, amino, alkylamino or dialkylamino, a sulphonyl group substituted by amino, alkylamino, dialkylamino or cyclic imino, whereby a methylene group in the 4-position can be replaced by a sulphur or oxygen atom, an alkylcarbonylamino, aminocarbonylamino or alkylaminocarbonylamino radical, an alkylthio, alkylsulphinyl or alkylsulphonyl radical, a nitro, halogen, amino, hydroxyl, alkyl, trifluoromethyl, alkoxy, alkenyloxy, alkynyloxy, cyanoalkoxy, carboxyalkoxy, alkoxycarbonylalkoxy, dialkylamino, 1-imidazolyl or cyano group; X is a valency bond, a C.sub.1 -C.sub.4 alkylene radical or a vinyl radical; and T is an oxygen or sulphur atom; the tautomers thereof and the physiologically acceptable salts thereof with inorganic and organic acids.The present invention also provides processes for the preparation of these compounds and pharmaceuticals containing them for the prophylaxis and treatment of heart and circulatory diseases.