The present invention provides a liquid formulation comprising at least 7 wt% of the total formulation of propylene glycol and: an effective amount of an inodilator selected from the group consisting of pimobendan and levosimendan and pharmaceutically or veterinary acceptable salts thereof； an angiotensin converting enzyme inhibitor selected from the group consisting of enalapril, benazepril, cilazapril, delapril, imidapril, moexipril, spirapril, temocapril, trandolapril, ramipril, quinapril, perindopril, lisinopril and pharmaceutically and veterinary acceptable salts thereof； or a combination of an inodilator selected from the group consisting of pimobendan and levosimendan and pharmaceutically or veterinary acceptable salts thereof and an angiotensin converting enzyme inhibitor selected from the group consisting of enalapril, benazepril, cilazapril, delapril, imidapril, moexipril, spirapril, temocapril, trandolapril, ramipril, quinapril, perindopril, lisinopril and pharmaceutically and veterinary acceptable salts thereof.
