The present invention relates to a phosphodiesterase type III (PDE III) inhibitor and/or Ca 2+ -sensitizing agent or a pharmaceutically acceptable derivative thereof for the treatment of a patient suffering from hypertrophic cardiomyopathy (HCM). According to another aspect the present invention relates to the use of a PDE III inhibitor and/or Ca 2+ -sensitizing agent for the preparation of a medicament for the treatment of a patient suffering from HCM.