虚血性心疾患に対する心血管作動薬OPC-8212の効果—β遮断剤，Metoprololとの比較検討

Effects of a new positive inotropic agent, OPC-8212 in patients with effort Angina:Comparison with β-blocker, Metoprolol

　近年，新しく開発された陽性変力効果を示す心血管作動薬，OPC-8212はすでに心不全に使用され，有効性が示されつつある。

　我々は，先に本剤が心拍数を変化させないことに着目し，その効果を冠狭窄後の虚血心で実験的に検討した。その結果，血行動態諸量の改善とともに虚血部心筋収縮期短縮長の増大，心筋CO₂，およびST偏位の減少を観察した^1）。この事実より，本剤が虚血部心筋障害を増大させることなく虚血部局所心筋機能を改善させ虚血性心疾患に基づく心不全にも使用可能であることが示唆された。

To investigate whether OPC-8212 improves exe-rcise induced ischemia or not, we studied 11 pa-tients with effort angina and positive exercise indu-ced ST depression. They underwent a symptom li-mited maximal bicycle ergometer exercise test with-out medication as the control exercise. Either OPC -8212 (60 mg/day) or metoprolol (60 mg/day) was administered in a random sequence for 7 days, and 7 days or more after the treatment, the alternate drug was also given for 7 days. The same exercise protocol as control was performed on the 7th day following each drug administration. Metoprolol dec-reased maximal heart rate (109±14 vs 128±18 beats/ min ; p<0.05), however OPC-8212 did not change heart rate (122±15 vs 128±18 beats/min). Neither drug changed maximal systolic blood pressure. OPC -8212 improved exercise induced ST depression compared with control (- 0.15 0.05 vs - 0.23±0.04 mV ; p <0.05) as did metoprolol (-0.18±0.05 vs -0.23±0. 04 mV ; p<0.05). Chest pain disappeared in 2 patients and was lessened in 2 patients by OPC-8212, whereas, following metoprolol treatment disappeared in 4 patients. It should be noted that metoprolol induced general fatigue during exercise in 2 patients. We concluded that OPC-8212 impro-ved exercise induced ischemia without change in heart rate or systolic blood pressure, although the mechanism of these effects is still unknown.