- Effects of sustained isometric handgrip on ventricular systolic time intervals in patients with ischemic heart disease. Inotropic state of the left ventricle during treatment with perhexiline maleate and with propranolol. Caponnetto, S., Iannetti, M., Pastorini, C., Masperone, M.A., Perugini, P., Oriani, G. Japanese heart journal. (1977)