たこつぼ型心筋症の発症にアミノフィリン投与が関与したと考えられる1症例

Takotsubo Cardiomyopathy Induced by Administration of Aminophylline:A case report

要旨　患者は76歳，男性．脳梗塞後遺症のためリハビリテーション目的で他院に入院中であった．第1病日，発熱と呼吸苦があり急性気管支炎の診断でアミノフィリン500mg静注を施行された．以後はアミノフィリン250mg連日点滴と抗生剤を開始された．第4病日に急激な呼吸苦の増悪を認め当院へ紹介された．心電図で前胸部誘導でST上昇を認めた．冠動脈造影検査では閉塞や狭窄病変はなかった．心エコーでは心尖部の無収縮と心基部の過収縮を認め，たこつぼ型心筋症と診断した．第12病日に施行した²⁰¹Tl/¹²³I-BMIPP心筋シンチグラムでは心尖部の壁運動低下に一致した血流-代謝ミスマッチ領域を認めた．第14病日の心エコーでは壁運動異常は改善していた．アミノフィリン投与による交感神経活性化が内因性カテコラミン増加を来し，たこつぼ型心筋症の発症に関与したと考えられた．

　A 76-year-old man was admitted to another hospital for rehabilitation after old cerebral infarction. Because of a fever and mild dyspnea at rest, he was diagnosed as having acute bronchitis. Intravenous aminophylline(500mg)was given initially. Then administration of intravenous aminophylline(250mg/day)and antibiotics was started every day. After 4 days, he suffered from severe dyspnea and was referred to our hospital. An electrocardiogram showed marked ST elevation in the precordial leads. There was no obstruction and no significant stenosis in the emergent coronary angiography. The initial echocardiography showed left ventricular wall motion abnormality with akinesis around the apical area and hyperkinesis at the basal portion. The diagnosis was takotsubo cardiomyopathy. Tallium-201(201Tl)and iodine-123-beta-methyl-p-iodophenyl penta-decanoic acid(123I-BMIPP)dual-isotope myocardial single-photon emission computed tomography(SPECT)showed myocardial perfusion and metabolism mismatch in the apical area. The wall motion abnormality completely recovered within the following two weeks. Thus, administration of aminophylline is thought to have led to transient left ventricular dysfunction, by means of adrenergic hyperstimulation of the heart with the potential for catecholamine cardiotoxicity.