Abstract: This medicinal composition for the treatment and prevention of the symptoms of heart failure contains, by way of active principle, at least one compound chosen from 2-amino-1-(2,5-dimethoxyphenyl)-1-propanol (methoxamine) and its pharmaceutically acceptable salts, and it is presented in a form which can be administered by inhalation (aerosol or nebulizate).It was demonstrated, in particular, that the administration of methoxamine-HCl by inhalation, at a unit dosage of 10 mg, in the form of a 2% (w/v) solution in physiological saline, decreases airways resistance in subjects suffering from decompensated left ventricular failure, and increases the exertion tolerance of patients suffering from compensated left vetricular failure, whether the latter is of ischemic origin or otherwise.