Abstract: Objective To investigate the effects of different training intensities on cardiopulmonary function in patients with coronary heart disease after percutaneous coronary intervention （PCI）. Methods A total of 100 patients with coronary heart disease who were hopitalized from July 2020 to February 2022 and successfully underwent PCI were selected and divided into a control group （50 cases） and a study group （50 cases） by random number table method. The control group （moderate intensity continuous training） had a maximum oxygen uptake （VO₂） of 40% to 59% or a maximum heart rate of 55% to 69% as the training load, while the study group （high intensity interval training） had a maximum VO₂ of >80% or a maximum heart rate of 85% to 95% as the training load. The two groups of patients exercised on an ergometer for 30 min per time, 3 times a week, for 4 consecutive weeks, and received conventional drug treatment. All patients underwent cardiac ultrasound and cardiopulmonary exercise test （CPET） before and after rehabilitation to evaluate cardiopulmonary function and exercise endurance. Results There were no significant differences in age, sex, and history of diseases between the two groups. Before rehabilitation, there were no significant differences in left ventricular ejection fractions （LVEF）, oxygen uptake at anaerobic threshold （VO₂ AT）, peak oxygen uptake （peak VO₂）, oxygen pulse, and ventilatory equivalent for carbon dioxide （VE/VCO₂） slope between the study group and the control group. The changes before and after rehabilitation in VO₂ AT, peak VO₂, oxygen pulse, and minute ventilation volume （VE） were significantly higher in the study group than in the control group （P<0.05）. Spearman correlation analysis showed that the change values of VO₂ AT, peak VO₂, oxygen pulse, and VE were positively correlated with training intensity （P<0.05）. Conclusions Compared with moderate intensity continuous aerobic exercise, high intensity interval aerobic exercise can better improve the aerobic metabolic capacity and exercise endurance of patients with coronary heart disease after PCI.

Key words: Coronary heart disease, Cardiopulmonary function, Training intensity