切迫早産に対するβ2刺激薬リトドリン静注が発症の誘因となったと思われる急性心筋梗塞の1例

A Case of Acute Myocardial Infarction during Intravenous Ritodrine Treatment for Preterm Labor

　症例は23歳，女性．1996年7月27日に妊娠25週の切迫早産で当院産婦人科に入院，リトドリンの持続静注を開始された．29日の午前2時に胸部圧迫感を自覚するが30分ほどで消失した．同日12時に再度胸部圧迫感が出現．心電図にてII,III,aV_F，V₅，V₆にST上昇，生化学検査にて心筋逸脱酵素の上昇を認め当科に紹介された．心エコー図では下壁領域の軽度壁運動低下を認めた．CPK最大値は同日18時の440IU／lで胸部圧迫感出現からの第3病日には正常化した．転科後，合併症の出現をみず経過した．妊婦に対するリトドリンの投与中に心筋梗塞を発症した例は，これまでに本邦では1例しかなく，本例は稀な症例と考えられた．

A 23-year-old woman at the 25 week gestation stage was admitted to our hospital because of preterm labor on July 27th. Ritodrine was injected continuously. At 2: 00 on July 29 th, she experienced chest pain for 30 minutes. At 12: 00 on the 29 th she experienced chest pain again. Electrocardiogram showed ST elevation in II, III, aV_F, V₅, V₆ and ST depression in V₁-V₃. Mild elevation of CPK and CPK-MB were recognized. Echocardiogram showed slight hypokinesis of the infe-rior wall. Ritodrine was stopped and chest pain disappeared at 13: 30. Peak CPK was 440 IU/l at 18: 00 on the 29 th. After that the patient experienced no more chest pain. She had no coronary risk factors and she hadn't experienced chest pain before, so we considered that ritodrine had caused acute myocardial infarction in this case.

There have been two reports of ST elevation and elevation of CPK during ritodrine infusion, including our case, in Japan.