The present invention provides new tricyclic benzotriazoles of the general formula: ##STR1## wherein Z is a hydrogen atom or an acyl radical, Y is an oxygen or sulphur atom or two hydrogen atoms and X is an oxygen or sulphur atom or a >CR.sub.1 R.sub.2 or >NR.sub.3 group, R.sub.1 is a hydrogen atom or an alkyl, alkenyl or cycloalkyl radical, R.sub.2 is a hydrogen atom or an alkyl, alkenyl or cyano group or a carbonyl group substituted by a hydroxyl, alkyl, alkoxy, amino, alkylamino, dialkylamino or hydrazino group or R.sub.2, together with R.sub.1, represents a cycloalkylene radical or R.sub.1 and R.sub.2 together form an alkylidene or cycloalkylidene radical and R.sub.3 is a hydrogen atom or an alkyl radical; the tautomers thereof and the physiologically acceptable acid-addition salts thereof with inorganic and organic acids.The present invention also provides processes for the preparation of these tricyclic benzotriazoles and pharmaceutical compositions containing them for the treatment of heart and circulatory diseases.