虚血性心疾患患者の運動負荷時の血行動態の変動

Changes in hemodynamics during exercise in patients with ischemic heart disease

　心疾患を対象とした運動負荷試験は，特に虚血性心疾患において胸痛の鑑別，潜在性虚血の有無などの診断に用いられてきた。一方，近年は運動生理学の発達により，運動時の循環反応について詳細な研究がなされ，運動負荷試験は心機能の評価，治療効果および予後の判定などの臨床に広く応用されている。しかし，その多くは運動負荷時の自覚症状，心電図，体血圧および心電図の観察所見などであり，運動負荷による心拍出量の変動を経時的に観察した報告は少ない。

　本報告は心電図ならびに観血的検査法にて確認された虚血性心疾患患者について，運動負荷時の心拍出量の変動を経時的に観察し，健常者のそれと比較することにより，虚血性心疾患患者の運動負荷による心機能の変化の特徴を検討してみた。

Changes in the cardiac outpt during exercise were monitored along with time in 20 patients with ischemic heart disease, and were then compared with those in 8 healthy subjects to study how the activity of their heart changed due to exercise. The tolerable capacity during exercise was lower in those groups of patients with ischemic heart disease, while the increase in heart rate immediately after exercise was almost the same in both groups. Com-pared to the healthy subjects, the increase in systolic pressure just after the start of the exercise was less in those groups of patients with ischemic heart dis-ease. The stroke volume for the healthy subjects showed on increase immediately after the start of the exercise and a gradual decline back to the original state afterwards, but for those patients with ischemic heart disease the mean stroke remained almost unchanged throughout the exercise and a slightly decrease immediately after exercise. Al-though the cardiac output due to exercise increased in both groups, the increase rate was lower among the patients with ischemic heart disease. In addition, the patients with ischemic heart disease showed that on increase in cardiac output was attributable to the increase in heart rate.