Effects of Respiratory Exchange Ratio on the Prognostic Value of Peak Oxygen Consumption and Ventilatory Efficiency in Patients With Systolic Heart Failure

Objectives The purpose of this analysis was to evaluate the prognostic characteristics of peak oxygen consumption (V o2 ) and the minute ventilation/carbon dioxide (VE/V co2 ) slope of different peak respiratory exchange ratios (RERs) obtained from cardiopulmonary exercise testing in patients with heart failure (HF). Background For patients with HF, peak V o2 and the VE/V co2 slope are used for assessing prognosis. Peak V o2 is assessed in association with peak RER ≥1.10, indicating maximal effort and prognostic sensitivity. Conversely, the VE/V co2 slope provides effort-independent prognostic discrimination. Methods Patients with HF scheduled to undergo cardiopulmonary exercise testing were enrolled. Patients were subclassified by peak RER (RER