Verapamilの血栓溶解療法に及ぼす効果

Effect of verapamil on myocardial infarct size estimated by serial 201-thallium single-photon emission tomography

　〔目的〕冠動脈血栓溶解療法（ICT）時のreperfusion injuryとそこに関与するCaイオンの動態に注目し，ICTに先立ちverapamilを投与し，verapamilのICTに及ぼす影響を核医学的に検討した。〔方法〕対象は発症6時間以内にICTを行った急性心筋梗塞19例で，逸脱酵素の推移，慢性期心機能，さらに急性期，1週，4週目に行った²⁰¹Tl SPECTにおける梗塞範囲（％Defect），viabilityの指標（Tl-uptake）を計測しその推移を比較検討した。〔結果〕再疎通時のverapamilの血中濃度は48±25ngであり，房室ブロック等の合併症は認めなかった。Peak CKMBはverapamil群348±136IU，（−）群397±217IUと差異を認あなかった。％Defectはverapamil群で有意の縮小傾向を示した。慢性期左室駆出率はverapamil群は，（−）群に比し有意の高値を示し，慢性期の運動負荷Tl-SPECTでは高率に再分布を認めた。〔結語〕ICT時，再灌流に先だちverapamilを投与すると，梗塞の進展，拡大は抑えられる傾向を示した。

To investigate the effects of intravenous verapamil (V) in ccronary thrornbolytic therapy, we serially observed the time course of perfusion of the myoca-dium by 201-thallium (Tl) SPECT in patients who were successfully reperfused within 6 hours from theonset. 201-Tl SPECT was attempted serially on the 1st-2nd day, the 7th-10th day and 28th-30th day. In addition to this, we calculated the count ratio of radioactivity of ^99mTc-PYP (CR) in the infarcted myocardium to sternum to evaluate intracellular up-take of calcium during reperfusion. The infarct size, estimated by % Defect decreased significantly in the patients treated with V. while it remained unchanged in the patients without it. In the patients with V, the left ventricular ejection fraction was more fa-vourable, and exercise-induced ischemia determined by redistibution of 201-Tl SPECT in the chronic phase was found more frequently. CR showed no difference between reperfused myocardium irrespec-tive of the treatment. In conclusion, verapamil was considered to enhance myocardial salvage carried out by reperfusion, and not to affect the influx of intra-cellular calcium into the injured myocytes.