Correct spelling for the English word "Mydaleine" is [mˈa͡ɪde͡ɪlˌa͡ɪn], [mˈaɪdeɪlˌaɪn], [m_ˈaɪ_d_eɪ_l_ˌaɪ_n] (IPA phonetic alphabet).
A poisonous ptomaine formed in putrefying liver and other viscera; it acts specifically upon the heart, causing arrest of its action in diastole.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.