P6061Changes in exercise capactiy of frailest patients with heart failure treated with standard exercise recommandations versus stroke volume response to exercise: a pilot study

Background: Peak exercise oxygen uptake (V·O2peak) and exercice capacity are strong factors for predicting mortality in heart failure patients (HF). Although considerable heterogeneity in the nature of exercise intolerance was found in HF patients, one third of them presented a central hemodynamic exercise limitation induced by the impairment to augment stroke volume (SV) during a cardiopulmonary exercise testing (CPET). Among the frailest HF subjects (V·O2peak <18.0 mL min–1 kg–1), SV moreover reached its peak levels at a submaximal exercise intensity (pSVmax) in 86% of patients. To improve exercice capacity of the frailest HF patients, the international guidelines recommended to prescribe moderate continuous intensity exercise (MICE) based on the heart rate value (HR) associated with the anaerobic threshold (VT1). However, the b-blockers interactions on ventilatory adaptations and the attenuated HR response to exercise generally observed in HF patients would induce a dissociation between VT1 and pSVmax. This might be taken into consideration for the exercise intensity prescription.