Effects of exercise training on cardiac output in subjects with heart failure with preserved ejection fraction (HFpEF) - a protocol for a systematic review and meta-analysis.

Background: Patients with heart failure with preserved ejection fraction (HFpEF) commonly experience exercise intolerance, resulting in reduced cardiorespiratory fitness. This is characterised by a decreased maximal oxygen uptake (V̇O), which is determined by the product of cardiac output (CO) and arteriovenous oxygen difference (a-vDO). While exercise training has been shown to improve V̇O in HFpEF patients, the effects on CO remain unclear.