The present invention relates to an L blocker or a pharmaceutically acceptable salt thereof for the treatment and/ or o prevention of a feline patient suffering from heart failure (HF). The invention also relates to improving the quality of life, improving the general health condition as well as a prolonging the life expectancy in feline patients suffering from heart failure and/or heart failure due to one or more of the following etiologies HCM, DCM, RCM, UCM and /or ARVC.