The Time From Anaerobic Threshold (AT) to Respiratory Compensation Point Reflects the Rate of Aerobic and Anaerobic Metabolism After the AT in Chronic Heart Failure Patients

The significance of the time from anaerobic threshold to respiratory compensation point (RCP-AT time) in patients with chronic heart failure was investigated. Thirty-seven patients with chronic heart failure (New York Heart Association class II or III) were enrolled into the study. Cardiopulmonary exercise testing was performed using breath-by-breath gas sampling. A bicycle ergometer was used, and incremental exercise testing was carried out. Anaerobic threshold, respiratory compensation point (RCP), and the slope of oxygen uptake (VO2) as a function of work rate (deltaVO2/deltaWR) were measured. A positive correlation (r=0.53) between RCP-AT time and deltaVO2/deltaWR was found. RCP-AT time was corrected for the whole exercise period (ramp exercise-RCP point), and the correlation between corrected RCP-AT time and deltaVO2/deltaWR was still present (r=0.46). There was no correlation between RCP-AT time and anaerobic threshold. These findings suggest that RCP-AT time is a new parameter that reflects the rate of the aerobic and anaerobic metabolism after AT.