Lactate concentration responses during a cardiopulmonary exercise test in Heart Failure with Preserved Ejection Fraction

Incremental exercise testing has been commonly used for the diagnosis of coronary artery disease or as a prognosis tool in cardiac population. Bruce's and modified Bruce's protocol are among the most used protocols in the literature. However, the functional impairment and low functional reserve in HFpEF patients limits its applicability due to balance issues when performing the test in a treadmill, and the high increments in external load, which may not be suitable for finding the appropriate workload associated to a given metabolic intensity during incremental test. In lack of a standardized protocol for the assessment of training zones in HFpEF, we propose a cross-sectional study for assessing the factibility of a submaximal incremental test in HFpEF patients. Our goal is to describe the relative frequency of patients who can safely perform the test, in addition, to assess the association between first ventilatory threshold and ear lobe blood lactate samples at a given workload. Finally to describe the rated perceived exertion associated to the ventilatory thresholds (VT1 and VT2).