A study was conducted to clarify training ability in the recovery phase after coronary artery bypass graft surgery (CABG) . Thirty-one patients who underwent CABG were divided into four groups according to the degree of revascularization and graft patency: complete revascularization with graft patency (group A), complete revascularization without graft patency (group B), incomplete revascularization with graft patency (group C) and incomplete revascularization without graft patency (group D) . In all patients, exercise training was started one month after CABG and continued for one month. Treadmill exercise testing was performed at three points during the clinical course (one month before CABG, one month after CABG and at the end of exercise training) . Functional aerobic impairment (FAT), myocardial aerobic impairment (MAT), peripheral circulatory impairment (PCI) and electrocardiogram were measured at these points. The results obtained were as follows:
1) FAI was improved significantly after CABG as compared with before CABG in groups A and C, and was also improved significantly after exercise training as compared with before training in groups A and C. The degree of improvement in FAI in group A was larger than in group C.
2) Althought MAT was improved significantly after CABG as compared with before CABG in groups A and C, it was improved significantly after exercise training as compared with before training only in group A.
3) PCI remained unchanged before and after CABG in all groups. However, it was improved significantly after training as compared with before training in groups A and C.
4) The number of patients with a positive finding in the exercise test was reduced by CABG in all groups, and was decreased by training only in group A. However, CABG produced a significant decrease in groups A, B and C.
In conclusion, the present findings suggest that while graft patency is probably a major factor, the degree of revascularization may play only a subsidiary role in determining trainability soon after CABG.

A study was conducted to evaluate the effects of exercise training for cardiac rehabilitation. 69 patients with coronary artery disease were assigned to a low intensity exercise training program, which lasted for 3 months. The target heart rate for the exercise program was set at 50-60% of maximal heart rate. For comparison, the study patients were divided into 2 groups. 25 patients who had undergone CABG were assigned to group A and 42 patients who had not undergone CABG were assigned to group B. A symptom-limited treadmill exercise test was performed before and after the exercise training program in each patient. Oxygen uptake (VO₂), SBP, HR and PRP were measured at rest, submaximal workload and workload at the end point during the treadmill exercise test.
In addition, FAT, LVI and PCI were calculated. The parameters measured before and after exercise training were compared in order to assess the effects of the exercise training program. Our findings showed that exercise training was effective for improving exercise tolerance and submaximal exercise capacity in patients with coronary artery disease, particularly those who had undergone CABG.

A study was conducted to clarify the effect of hyperoxia (HO) on exercise tolerance andhemodynamics in patients with ischemic heart disease (IHD) . The subjects were 10 patients with serious IHD who showed ischemic ST depression during low-intensity exercise testing. In all subjects, cardiopulmonary exercise testing (CPX) was performed using two types of inhalation : normoxia (NO) and HO (O₂: 60%, N₂: 40%) . Heart rate (HR), blood pressure (BP), rating of perceived exertion (RPE), elapsed exercise duration and pressure rate product (PRP) were measured, and ECG was recorded during CPX according to the Bruce protocol. The peak oxygen uptake (VO₂peak) was calculated using the appropriate formula. These data were compared between the NO and HO groups, and the following results were obtained.
ST depressions on ECG, BP, HR and PRP after 20 min of rest showed no changes under NO. The other hand, only ST depression was improved after 20 min of rest under HO. The exercise duration in HO group was longer than in the NO group, and the VO₂peak in the HO group was higher than in the NO group. However, peak RPE showed no significant difference between the HO and NO groups. The incidence of ST depression as an endpoint of CPX showed no significant difference between the two groups. BP, HR and PRP at the CPX endpoint showed no significant differences between the HO and NO groups. In patients whose exercise duration was prolonged beyond the mean value by HO, peak HR and PRP were increased significantly. However, this tendency was not seen in patients whose exercise was prolonged for less than the mean value.
In conclusion, these results suggest that an increase in the oxygen supply to peripheral working muscles may play an important role in increasing exercise tolerance under HO in IHD patients.