虚血性心疾患の運動療法—Trainabilityに関する基礎的検討

Exercise traiming of patients with ischemic heart disease:preliminary study on thier trainabilities

　心臓にすでに障害を有する虚血性心疾患（IHD）について積極的に運動療法を行うことにはそれなりのリスクを伴うが，IHDの運動療法には2次予防の面で大きな関心が寄せられている^1,2）。その意味で真に有効であるか否かはなお不明であるが，運動療法によってIHDを有する患者でも身体適性を増しうることは多くの研究で示されている^3〜6）。わが国ではIHDに対する運動療法があまり積極的に行われていないので，これらの点に関する成績はほとんど報告されていない。今回は，これまでわれわれが行ってきた混合監視型の運動療法を^7），IHDについてに12週間行った際に得られる身体的側面の効果，主として酸素輸送系に対する急性の効果について述べるとともに，運動療法の効果の発現を阻害する要因として冠循環障害の状況と肥満の影響についても言及し，IHD患者のTrainabilityに関して考察する。

In Japan, there have not been enough experi-ences concerning patient selection for the exercise training and trainability of the patient with IHD. We have tried to summarize the effects of train-ing on the oxygen transport system and predic-tive view concerning trainability of patient with IHD. Thirty four male patients (54±8 years), 23 with myocardial infarction, 3 after—bypass surgery, 6 with angina pectoris and 2 with ischemic ECG abnormalities were selected for the study. We have developed our own system for exercise named as semi-supervised training that is characterized by one medically supervised training at the institute and at least two unsuper-vised home trainings in a week for 12 weeks. Symptom limited maximal stress testing after Bruce's protocol was performed on all subjects and the target heart rate for the training was determined as 70 to 85% of the maximal heart rate. Effects of exercise training were assessed with results of stress testing performed before, at 6 th and 12 th week after the initiation of theprogram.

After 12 week training, resting heart rate showed significant decrease and decreases in the heart rate, systolic pressure and pressure rate product at submaximal level were observed. Treadmill time was significantly prolonged from 518±121 to 660+121 seconds (P<O.001) with increase in VO₂ max from 26.8±5.1 to 30.2±5.5 ml/min･kg (P<0.05). Normalized TMT (TMTn) was also increased from 87+19 to 112 ±27% (P<0.001). No improvements in physical fitness after 12 week training were observed in three patients, whose invasive tests revealed severe coronary lesions characterized by threevessel disease and two vessel disease equivalent to the left main coronary stenosis.