A pharmaceutical composition comprising (S)-methyl-3-[4-(2-hydroxy-3-isopropylamino)propoxy]phenylpropionate in a concentration between about 75 mM and about 150 mM, which is substantially free of the R-isomer or pharmaceutically acceptable salt thereof, is provided. A method of treating a cardiac disorder is also provided and includes administering to a subject in need thereof a therapeutically effective amount of a pharmaceutical composition comprising (S)-methyl-3-[4-(2-hydroxy-3-isopropylamino)propoxy]phenylpropionate hydrochloride, wherein the (S)-methyl-3-[4-(2-hydroxy-3-isopropylamino)propoxy]phenylpropionate hydrochloride is present at a concentration between about 75 mM and about 150 mM and wherein the pharmaceutical composition is substantially free of (R)-methyl-3-[4-(2-hydroxy-3-isopropylamino)propoxy]phenylpropionate or pharmaceutically acceptable salt thereof.(S)-メチル-3-[4-(2-ヒドロキシ-3-イソプロピルアミノ)プロポキシ]フェニルプロピオナートを約75mMと約150mMの間の濃度で含む薬学的組成物であって、該フェニルプロピオナートのR-異性体または薬学的に許容し得るその塩を実質的に含んでいない該薬学的組成物が提供される。心臓障害を処置する方法も提供され、この方法には、該処置を必要とする被験体へ(S)-メチル-3-[4-(2-ヒドロキシ-3-イソプロピルアミノ)プロポキシ]フェニルプロピオナートヒドロクロリドを含む治療有効量の薬学的組成物を投与するステップが含まれる。