De invloed van training op de zuurstofkinetiek bij patiënten met chronisch hartfalen: Resultaten van een pilotstudie

Exercise training can improve exercise capacity and quality of life for patients with chronic heart failure. Data obtained at maxima[exercise may not be suitable to quantify the effects of training, because they depend heavily on the subject's motivation. There is therefore increasing interest in objective parameters based on sub-maximal exercise to measure training effects in such patients. Oxygen kinetics describe the rate of change in oxygen uptake during or after sub-maximal exercise. The main determinants of oxygen kinetics are changes in cardiac output and the ability of skeletal muscles to utilise oxygen, which can be improved by exercise training. The purpose of this pilot study was to determine whether oxygen kinetics can be used to measure training effects in patients with chronic heart failure due to systolic left ventricular dysfunction, and to compare them with other variables derived from submaximal exercise, such as the heart rate during and after exercise. In six patients who completed the full twelve-week exercise training programme, oxygen consumption at the anaerobic threshold and at peak exercise improved. Neither the heart rate at sub-maximal exercise nor the decline in heart rate after maximal exercise showed any change. However, the off-kinetics after sub-maximal exercise at 50% of their peak-VO₂ did improve significantly. The results of this study suggest that, unlike the heart rate response, VO ₂ off-kinetics at sub-maximal exercise are a useful tool to evaluate the effects of training in patients with chronic heart failure.